CONGRESS OF THE UNITED STATES

CONGRESSIONAL BUDGET OFFICE

A

CBO

STUDY

MAY 2005

Options for 

Restructuring

the Army

The Congress of the United States O Congressional Budget Office

CBO

Options for Restructuring the Army

May 2005

A

STUDY
Notes

Unless otherwise indicated, all dollar figures in this report are in 2006 dollars of budget 

authority, and all years are federal fiscal years (which run from October 1 to September 30).

Numbers in the text and tables may not add up to totals because of rounding.

The Congressional Budget Office’s (CBO’s) estimates of defense investment and operations 

costs through 2022 are based on the fiscal year 2005 Future Years Defense Program, on CBO’s 

projections of the long-term implications of that program, and on widely used cost relationships and methods. However, such long-term projections are inherently uncertain.

The cover photo, showing a member of the Army’s 2nd Infantry Division in Tall Afar, Iraq, 

was taken by Sgt. Jeremiah Johnson. It is used courtesy of the U.S. Army.
Preface

The U.S. Army has seen its missions grow in number and intensity in recent years with 

the global war on terrorism and the invasion and occupation of Iraq. The resulting levels of 

stress that have been placed on the Army’s active and reserve components have generated public debate about whether the Army’s present organization is adequate for the roles that the service is playing now and will play in the foreseeable future. At the same time, the Army has 

begun an extensive restructuring effort, called “modularity,” that is designed to significantly 

alter how the service is organized and how it operates in the field.

This Congressional Budget Office (CBO) study—prepared at the request of the House Committee on Armed Services—examines the Army’s capability to fight wars, sustain long deployments, and deploy rapidly to overseas operations, as well as its dependence on personnel and 

units in the reserve component. This study also analyzes eight options for restructuring the 

Army, each of which would either increase the Army’s ability to perform some types of missions or decrease its reliance on the reserve component. The options offer a broad overview of 

the general types of policy choices and trade-offs that decisionmakers will face when considering the size, structure, and capability of any plan for reorganizing the Army. In keeping with 

CBO’s mandate to provide impartial analysis, this study makes no recommendations.

Adam Talaber of CBO’s National Security Division wrote the study, under the general supervision of J. Michael Gilmore. Jason Wheelock and David Newman of CBO’s Budget Analysis 

Division prepared the cost estimates, under the general supervision of Jo Ann Vines. Frances 

Lussier provided guidance and advice during the writing of this report, and Douglas Hamilton, David Moore, Barbara Edwards, Arlene Holen, and Elizabeth Robinson provided 

thoughtful comments on an earlier draft. In addition, Andrew Krepinevich of the Center for 

Strategic and Budgetary Assessments and John Tillson of the Institute for Defense Analyses 

offered valuable insights and comments. (The assistance of external participants implies no 

responsibility for the final product, which rests solely with CBO.) 

Janey Cohen and Christian Spoor edited the study, and Christine Bogusz proofread it. Cindy 

Cleveland produced drafts of the manuscript. Maureen Costantino produced the cover and 

prepared the study for publication, and Annette Kalicki and Simone Thomas prepared the 

electronic version for CBO’s Web site (www.cbo.gov).

Douglas Holtz-Eakin

Director

May 2005

Summary xi

1 The Army’s Current and Planned Structure 1

The Army’s Force Structure Prior to Modularity 1

How Army Units Are Used in the Field 3

Concerns with the Premodular Structure 4

Planned Changes in the Army’s Structure 8

2 Alternatives for the Army’s Force Structure 13

Policy Choices and Their Implications 13

Measures for Evaluating the Effects of Changing the 

Army’s Force Structure 14

Alternatives That Would Increase the Size of the Army 19

Alternatives That Would Reduce Dependence on the 

Reserve Component 24

Alternatives That Would Create New Types of Units 31

A Detailed Descriptions of Current and Proposed Army Units 47

Theaters 49

Corps 50

Divisions 51

Brigades 53

New Units from the Options in This Analysis 60

CONTENTS
vi OPTIONS FOR RESTRUCTURING THE ARMY

B The Army’s Plan for Modularity 63

Overview of Modularity 63

Assumptions About the Impact of Modularity on the 

Army’s Force Structure 65

Implications for Warfighting 68

Implications for the Army’s Ability to Sustain Extended 

Deployments 71

Implications for the Army’s Dependence on the Reserve 

Component 71

Implications for Deployment Speed 72

C The Measures of Army Capability Used in This Study 73

Size and Composition of the Force 73

Cost of the Force 75

Ability to Fight Wars 75

Ability to Sustain Extended Deployments 80

D How CBO Estimated the Costs of Options for Restructuring the Army 83

Methods for Estimating Investment Costs 83

Methods for Estimating Operation and Support Costs 84

Results of the Cost Analysis 85
CONTENTS vii

Tables

S-1. Number of Army Personnel and Units xiii

S-2. Alternative Force Structures Examined in This Analysis xv

S-3. Comparison of Alternatives with the Army’s Premodular

Force Structure xvi

1-1. Number of Major Combat Units and Personnel in Those Units

in Premodular and Modular Forces 9

2-1. Size and Composition of the Premodular Army 15

2-2. Cost of the Premodular Army 15

2-3. The Premodular Army’s Ability to Fight Wars 16

2-4. The Premodular Army’s Ability to Sustain Extended Deployments 16

2-5. Sizes of Past U.S. Peacekeeping and Occupation Forces 17

2-6. Effects of Alternative 1A on the Size and Composition of the Army 20

2-7. Effects of Alternative 1A on the Cost of the Army 20

2-8. Effects of Alternative 1A on the Army’s Ability to Fight Wars 21

2-9. Effects of Alternative 1A on the Army’s Ability to Sustain Extended 

Deployments 22

2-10. Effects of Alternative 1B on the Size and Composition of the Army 22

2-11. Effects of Alternative 1B on the Cost of the Army 23

2-12. Effects of Alternative 1B on the Army’s Ability to Fight Wars 24

2-13. Effects of Alternative 1B on the Army’s Ability to Sustain Extended 

Deployments 25

2-14. Effects of Alternative 2 on the Size and Composition of the Army 26

2-15. Effects of Alternative 2 on the Cost of the Army 26

2-16. Effects of Alternative 2 on the Army’s Ability to Fight Wars 27

2-17. Effects of Alternative 2 on the Army’s Ability to Sustain Extended 

Deployments 28

2-18. Effects of Alternative 3 on the Size and Composition of the Army 28

2-19. Effects of Alternative 3 on the Cost of the Army 29

2-20. Effects of Alternative 3 on the Army’s Ability to Fight Wars 30

2-21. Effects of Alternative 3 on the Army’s Ability to Sustain Extended 

Deployments 31
viii OPTIONS FOR RESTRUCTURING THE ARMY

2-22. Effects of Alternative 4 on the Size and Composition of the Army 32

2-23. Effects of Alternative 4 on the Cost of the Army 32

2-24. Effects of Alternative 4 on the Army’s Ability to Fight Wars 33

2-25. Effects of Alternative 4 on the Army’s Ability to Sustain Extended 

Deployments 34

2-26. Effects of Alternative 5 on the Size and Composition of the Army 35

2-27. Effects of Alternative 5 on the Cost of the Army 36

2-28. Effects of Alternative 5 on the Army’s Ability to Fight Wars 37

2-29. Effects of Alternative 5 on the Army’s Ability to Sustain Extended 

Deployments 38

2-30. Effects of Alternative 6 on the Size and Composition of the Army 39

2-31. Effects of Alternative 6 on the Cost of the Army 40

2-32. Effects of Alternative 6 on the Army’s Ability to Fight Wars 41

2-33. Effects of Alternative 6 on the Army’s Ability to Sustain Extended 

Deployments 42

2-34. Effects of Alternative 7 on the Size and Composition of the Army 43

2-35. Effects of Alternative 7 on the Cost of the Army 44

2-36. Effects of Alternative 7 on the Army’s Ability to Fight Wars 45

2-37. Effects of Alternative 7 on the Army’s Ability to Sustain Extended 

Deployments 46

B-1. Potential Size of the Modular Army 66

B-2. Number and Types of Brigades in Premodular and Modular Forces 70

D-1. Summary of Incremental Costs or Savings for Options to 

Restructure the Army 86

Figures

A-1. Symbols of Unit Size 47

A-2. Symbols of Unit Type 48

A-3. Structure of an Army Theater 49

A-4. Structure of an Army Heavy Corps 50

A-5. Structure of an Army Heavy Division Under Various Designs 51

Tables (Continued)
CONTENTS ix

A-6. Structure of an Army Light Division Under the Army of 

Excellence Design 53

A-7. Structure of an Army Heavy Brigade Under Various Designs 54

A-8. Structure of an Army Armored Cavalry Regiment 56

A-9. Structure of an Army Medium (Stryker) Brigade 57

A-10. Structure of an Army Light Brigade Under Various Designs 58

A-11. Structure of a Notional Stabilization and Reconstruction Division 59

A-12. Structure of Notional Heavy and Light Army Expeditionary Forces 60

B-1. Army Command Levels Before and After Modularity 65

C-1. Amount of Equipment Deployed over Time by Airlift or Sealift 80

Box

1-1. Army Command Levels 4

Figures (Continued)

Summary

Military operations associated with the global 

war on terrorism, especially the invasion and occupation 

of Iraq, have greatly increased the number and intensity 

of the Army’s missions. With the exception of the 2nd Infantry Division (which is stationed in South Korea), all 

10 combat divisions in the active component of the Army 

have been deployed at least once to Afghanistan or Iraq, 

and many have returned there or are scheduled to return. 

In addition, the Army has mobilized and deployed an increasing number of combat brigades from the National 

Guard; it now depends on the Guard’s combat forces to a 

degree not seen in the more than 50 years since the Korean War. That dependence, combined with the Army’s 

need to mobilize and deploy support units from the 

Army Reserve and National Guard, has required the 

Army to sustain a higher level of mobilization than the 

modern reserve system has experienced before.1

As it conducts operations, the Department of Defense 

(DoD) is seeking to increase the speed with which Army 

forces can be deployed overseas. Concerns about speed 

arose with the lengthy deployment required for Operation Desert Storm in the early 1990s; those concerns 

arose again during the U.S. intervention in Kosovo in 

1999 and, more recently, when difficulties arose in deploying the 4th Infantry Division to Operation Iraqi 

Freedom. Deployment speed is directly related to the size, 

weight, and flexibility of Army formations. Some observers believe that those formations are not agile enough to 

prosecute the sorts of military operations that are likely in 

the future.

Concerns about the pace of operations and about deployment speed have led numerous Members of Congress, 

DoD officials, and outside analysts to question whether 

the current size and composition of the Army is appropriate. In particular, they ask: 

B Does the Army have enough forces, and the right kind 

of forces, to respond to contingencies that may arise 

other than the missions in Afghanistan and Iraq—that 

is, does the Army have sufficient ability to fight wars?

B Does the Army have enough forces, of the right kind, 

to sustain the occupation of Iraq or to conduct a similar operation requiring the stabilization and reconstruction of a sizable country—that is, does the Army 

have sufficient “peacekeeping” ability?

B Should the Army be structured to rely heavily on reserve personnel for the long periods that are associated 

with stabilization and reconstruction operations?

B Is the Army capable of responding to crises and deploying to distant theaters of operations quickly?

The concerns underlying those questions have led defense 

officials and lawmakers to take a number of actions in 

recent years. The Army’s Chief of Staff, General Peter 

Schoomaker, has launched a reorganization plan—called 

“modularity”—that is intended to increase the number of 

combat units available to the Army while making those 

units more flexible, more self-contained, and faster to 

deploy. In addition, two of the Army’s ongoing efforts—

to introduce Stryker armored vehicles and eventually to 

replace the current mix of tanks and armored vehicles 

with families of light armored vehicles through the Future Combat Systems (FCS) program—are intended to 

increase the responsiveness and deployment speed of 

Army units. To help carry out the modularity plan, the 

Secretary of Defense has given the Army temporary authority to add up to 30,000 soldiers to the active component. Subsequently, in the 2005 defense authorization 

act, lawmakers authorized the Army to increase the permanent end strength of the active component by 20,000 

personnel.

In addition, the Secretary of Defense has ordered all of 

the military services to find ways to reduce dependence 

1. As used in this study, “reserve” refers to the Army’s reserve component (the Army Reserve and the Army National Guard), and 

“active” refers to the service’s active component.
xii OPTIONS FOR RESTRUCTURING THE ARMY

on their reserve components. DoD has also adopted a 

new set of Joint Swiftness Goals that establish very challenging targets for how fast forces must be able to deploy 

to operations.

This study by the Congressional Budget Office (CBO) 

examines various ways in which the Army could be restructured to address the concerns outlined above. CBO’s 

analysis compares the costs of alternative force structures 

as well as quantitative measures of their capability for 

warfighting, peacekeeping, reliance on the reserves, and 

deployment speed. The analysis points to several general 

conclusions about the possibilities for restructuring the 

Army:

B Alternatives that would significantly improve the 

capabilities measured by CBO would require more 

personnel and have higher costs. Within current budgetary and personnel constraints, there is only limited 

potential to increase the Army’s warfighting and 

peacekeeping capabilities substantially, to trade one 

kind of capability for another, or to decrease the service’s reliance on the reserves.

B The modularity initiative will boost the number of 

combat forces available to the Army by up to 5 percent. But it may require an additional 60,000 personnel to do so (or twice the temporarily authorized increase), and it will make the Army more reliant on 

reserve support units. Moreover, modularity is unlikely to lead to substantial improvements in deployment times.

B The number of support forces that the Army normally 

uses with major combat units means that even relatively small increases in combat units would require 

significant increases in personnel. The Army could 

boost the number of major combat units without adding many personnel by reducing the level of support 

provided to combat units. However, doing that would 

raise the level of risk in warfighting, according to 

present Army doctrine.

B In its current structure, the Army is dependent on reserve forces for conducting even relatively small operations.2 Eliminating that dependence so that the active 

Army could operate without extensive reserve mobilization would require either greatly increasing the size 

of the active Army or substantially lessening its combat power. However, the service could reduce the level 

of reserve mobilization needed to sustain peacekeeping 

operations by reallocating the types of support units 

that are located in the active and reserve components.

B Proposals to create dedicated “peacekeeping” formations in the Army would be unlikely to produce a sizable increase in the number of soldiers that the Army 

could deploy to peacekeeping operations. Such formations might have qualitative advantages, but CBO 

found that converting combat forces to peacekeeping 

forces would not significantly increase the number of 

soldiers that the Army could sustain in extended 

deployments.

B Proposals to field “medium-weight” formations 

equipped with Stryker vehicles would not improve 

deployment times substantially.

B Proposals to restructure the Army to employ fewer, 

smaller, lighter combat units equipped with advanced 

weaponry (such as the FCS) could improve deployment times slightly. However, those proposals would 

significantly decrease the number of soldiers that the 

Army could deploy to peacekeeping operations.

B Proposals to eliminate some layers of command structure (such as the corps level) would be unlikely to reduce the size of the Army or speed up deployment as 

long as the general types and numbers of support units 

included in those command levels were retained.

B The Army could improve deployment times substantially by investing in additional sealift assets (transport 

ships), prepositioning more equipment closer to potential theaters of operations, and making some organizational changes. Although such steps would entail 

up-front costs, they would be less expensive over the 

long run than the Army’s current plans.

The Army’s Force Structure 

Before Modularity 

Before the Army began making changes as part of its 

modularity plan (described below), its force structure had 

been relatively stable since the mid-1990s. That structure 

was based around fielding 10 active divisions, eight Na2. Although the Army has begun implementing the changes associated with modularity, in this study the “current” force refers to the 

premodular force, for simplicity.
SUMMARY xiii

Summary Table 1.

Number of Army Personnel and Units

Source: Congressional Budget Office.

a. Personnel numbers are rounded to the nearest 5,000.

b. Includes people in training or between assignments.

c. Heavy brigades are equipped with tanks and other armored vehicles. Medium brigades are equipped with the Army’s new Stryker light 

armored vehicle. Light brigades consist of various types of infantry without armored vehicles, including airborne and air assault units. The 

numbers shown here include brigades that are part of divisions as well as separate brigades.

tional Guard divisions, and numerous separate brigades 

(see Summary Table 1). When combat divisions or brigades are deployed to a major operation, they require significant numbers of support units that perform various 

functions, such as units for logistics, field hospitals, communications networks, construction engineers, additional 

artillery, and many others. Those support units are generally grouped under higher-level commands, such as the 

corps (intended to support two to five divisions) or the 

theater (intended to support one or more corps). The 

Army also has a large number of personnel who are not 

assigned to combat or support units. They include trainees, “transients” (people in transit between assignments), 

and personnel assigned to administrative units. 

The Army’s combat units are categorized by how they are 

equipped and trained to fight. “Heavy” units are 

equipped with tanks and other armored vehicles; they are 

intended for combat against other armored forces in relatively open terrain. “Light” units are various types of 

infantry without armored vehicles, including airborne 

and air assault units, such as the 82nd Airborne Division. 

“Medium” units are relatively new and are equipped with 

the Army’s new Stryker light armored vehicle. The Army 

introduced medium forces in the past few years in part 

because of concerns about the deployability of heavy 

forces, which require significant lift assets (transport 

planes and ships) to move, and about the firepower of 

light forces, which are not equipped for the most intense 

combat. 

Since the 1970s, the Army has integrated its active and 

reserve components under what is known as the Total 

Force Policy. The Army’s implementation of that policy 

has involved concentrating combat units in the active 

component and units that support combat units in the 

reserve component. Consistent with that policy, the 

Army Reserve does not contain any combat units but instead is organized entirely to support units in the active 

component. The Army National Guard includes eight 

combat divisions. In general, the Army does not plan to 

deploy those divisions to combat theaters; instead, they 

are given missions such as homeland defense or forming 

part of the strategic reserve. As such, the Army does not 

170,000 0 170,000 340,000

140,000 145,000 145,000 430,000

175,000 60,000 35,000 270,000

______ ______ ______ _______

Total 485,000 205,000 350,000 1,040,000

10 0 8 18

17 0 22 39

3 0 03

13 0 14 27

__ _ __ __

Total 33 0 36 69

Medium 

Light 

Active Army

Administrative Units and Individualsb

Units

Divisions

Brigadesc

Personnela

Divisions and Separate Brigades

Corps- and Theater-Level Support Units

Army

National Guard Total Army

Heavy 

Army Reserve
xiv OPTIONS FOR RESTRUCTURING THE ARMY

field support units for most of those divisions. The rest of 

the National Guard consists of separate combat brigades, 

which the Army does plan to deploy to combat theaters, 

and support units, which are intended to support either 

the separate Guard brigades or active units. The result of 

that division of responsibility is that combat units in the 

active Army depend heavily on support units in the reserves, and it is extremely difficult for the Army to engage 

in any major operation without mobilizing reserve personnel.

In CBO’s analysis, active and National Guard combat 

brigades for which the Army has a full set of support 

units are referred to as “supported brigades.” National 

Guard combat brigades for which the Army does not 

have a full set of support units are referred to as “unsupported brigades.” All brigades are considered either supported or unsupported.

Planned Changes to the Army’s 

Force Structure

In February 2004, the Chief of Staff of the Army announced a plan to reorganize the Army’s forces into a 

larger number of smaller, more “modular” combat brigades. That plan envisions increasing the number of combat brigades in the active Army from 33 to 43 (and possibly to 48, pending future decisions) while reducing the 

number of combat brigades in the National Guard from 

36 to 34. Each of the new modular brigades would have 

one-third fewer subordinate combat units than traditional brigades do but would have more support units, 

thus theoretically allowing the brigades to be deployed in 

a more independent manner. To establish the new brigades, the Secretary of Defense has given the Army 

authorization for up to 30,000 additional soldiers. Currently, that authorization is only temporary, since the 

Army intends to find other areas where it can reduce the 

number of required personnel by an equivalent amount. 

In 2004, the Army began the process of reorganizing 

units and adding the brigades.3

Besides reorganizing its forces, the Army is planning to 

reequip them by replacing most of its current ground 

combat equipment with the Future Combat Systems. 

According to the Army, the FCS will include a network of 

sensors, munitions, and communication links that would 

enable a force of medium-weight armored vehicles to 

fight with the power and survivability of today’s heavy 

forces. When the FCS is fully fielded, the Army expects 

units equipped with it to require fewer personnel and 

deploy more quickly than current units do. The Army 

expects to equip existing units with some FCS sensors 

and networks fairly soon, but it anticipates that fully 

equipping all combat brigades with the FCS will take 

several decades. CBO estimates that once the FCS program enters full production, it will cost about $7 billion 

to $9 billion per year to procure until the Army is fully 

equipped.

Alternatives for Restructuring 

the Army

The Army could respond in many different ways to the 

concerns that have been raised about its ability to fight 

wars, its peacekeeping capability, its dependence on the 

reserves, and its deployment speed. This analysis examines eight alternative approaches to reorganization that 

would address those concerns (see Summary Table 2). 

Some of the alternatives would alter the size of the Army; 

others would change the distribution of units between 

the active and reserve components or create new types of 

units. The options incorporate features of proposals made 

by various participants in the public debate. Those features illustrate some of the important trade-offs and constraints involved in restructuring the Army.

None of the alternatives are based on the Army’s modularity plan because that plan has not been developed in 

enough detail to allow CBO to analyze it fully. To date, 

the Army has not announced the number or type of support units that modularity will require, nor has it incorporated modularity into its more detailed budget plans, 

such as the Future Years Defense Program (FYDP).4

 For 

that reason, CBO’s analysis compares each alternative 

with the Army’s preexisting structure (before the changes 

being made as part of the modularity reorganization). 

However, the analysis does look at the potential implications of modularity for each alternative. (In addition, 

3. As of this writing, DoD has not yet decided how to respond to the 

permanent increase of 20,000 in end strength included in the 

2005 defense authorization act.

4. DoD did not include modularity costs in the 2005-2009 FYDP, 

and it plans to include only limited cost information in the 2006-

2011 FYDP. DoD has decided that substantial funding for modularity over the next few years should come from supplemental 

appropriations, but to date, supplemental requests have not provided details about funding requirements for modularity.
SUMMARY xv

Summary Table 2.

Alternative Force Structures Examined in This Analysis

Source: Congressional Budget Office.

Appendix B presents more information about modularity 

and some of the issues it may involve.) 

Because the details of the Army’s modularity plan are still 

fluid, CBO estimated the costs of the alternatives relative 

not to that plan but to the costs of forces in DoD’s 2005 

FYDP and in CBO’s long-term projection of the implications of that program.5 CBO divided the estimate for 

each option into investment costs, which include the 

costs of developing and purchasing equipment for units, 

and operation and support (O&S) costs, which include 

compensation for military personnel and the peacetime 

costs of units’ day-to-day operations. For each option, 

CBO also estimated the annually recurring O&S costs 

that would continue after the projection period. If the 

Army retained its current force structure, its investment 

costs would total $605 billion through 2022, and its 

O&S costs would total $1,488 billion. (All estimates are 

in 2006 dollars.) By the end of that period, annual O&S 

costs would amount to about $100 billion. The alternaAlternative Major Changes Issues Addressed Trade-Off

1A: Add Two Adds two active combat divisions Warfighting Cost

Active Divisions Increases active and reserve end strength Peacekeeping

1B: Add Two Active Adds two active combat divisions Warfighting Risk from having 

Divisions by Reducing Reduces artillery and air-defense support units Peacekeeping less support

Support Forces

2: Reallocate Support Converts peacekeeping support units to active units Dependence on Relatively high 

Forces Between the Active Converts warfighting support units to reserve units reserves dependence on reserves 

and Reserve Components Eliminates Total Force Policy for peacekeeping Peacekeeping for fighting wars

3: Eliminate the Army’s Adds active support units and personnel Dependence on Cost

Dependence on Reduces reserve support units and personnel reserves

Reserve Support Units Completely eliminates Total Force Policy

4: Organize Stabilization Creates five “peacekeeping” divisions Peacekeeping Loss of warfighting ability

and Reconstruction Cuts two active combat divisions

Divisions May yield qualitative improvements in peacekeeping

5: Convert to a Brigade- Changes Army into a mix of combat and support groups Deployment speed Relatively high risk from 

Based Army Eliminates corps and division Warfighting having less support

May yield qualitative improvements in warfighting

6: Convert to an Structures the Army to resemble the Marine Corps Deployment speed Up-front cost

Expeditionary Army Buys additional sealift assets and prepositioned 

materiel

7: Convert to a Emphasizes light units with greater firepower Deployment speed Loss of peacekeeping 

Transformational Army Cuts four active combat divisions Warfighting ability

May yield qualitative improvements in warfighting

5. CBO’s projections of DoD’s long-term spending plans are contained in Congressional Budget Office, The Long-Term Implications of Current Defense Plans: Summary Update for Fiscal Year 

2005 (September 2004), and The Long-Term Implications of Current Defense Plans: Detailed Update for Fiscal Year 2005 (September 2004). The 2005 FYDP runs through 2009, and CBO’s longterm projections run through 2022.
xvi OPTIONS FOR RESTRUCTURING THE ARMY

Summary Table 3.

Comparison of Alternatives with the Army’s Premodular Force Structure

Continued

Source: Congressional Budget Office.

a. The ratio of support personnel to combat personnel in a full combat force. Higher values indicate that combat units have access to greater 

levels of support.

b. Total investment and operation and support costs between 2006 and 2022, in 2006 dollars. For the current force, those costs are based on 

the 2005 Future Years Defense Program and on CBO’s long-term projection of its implications.

tives in this analysis would range from costing an additional $333 billion over the 2006-2022 period to saving 

$314 billion (see Summary Table 3).

CBO also developed measures to compare each alternative’s force structure with the Army’s premodular force 

structure in several areas besides cost:

B The total number of combat brigades in the Army and 

the number of fully supported combat brigades that 

would be available for warfighting;

B The total number of personnel that could be sustained 

overseas for extended peacekeeping deployments;

B The number of reserve personnel who would have to 

be mobilized to support extended peacekeeping deployments; and

B The time that the Army would need to deploy a brigade, a division, a corps, or a full theater’s worth of 

forces to a combination of distant theaters.

Those measures are intended to permit a quantitative 

comparison between alternatives. They do not, and cannot, encompass all of the possible effects of reorganizing 

the Army. Proponents of particular changes to the Army 

might argue that qualitative effects are the most important elements of their proposals. However, CBO’s analysis 

focuses on quantitative measures and does not incorporate those effects.

Alternatives That Would Increase 

the Size of the Army

The first two options that CBO analyzed illustrate the effects of expanding the Army. Many observers believe that 

expansion is necessary to improve the Army’s ability to 

deal with missions like the occupation of Iraq, to respond 

to other threats that may arise during that occupation, or 

to reduce stresses on the reserve component. Alternatives 

1A and 1B would both expand the Army by two divisions, but in different ways.

Alternative 1A—Add Two Active Divisions. This option 

would increase the size of the Army’s combat forces by 

Current Force 482,400 555,000 55 69 1.76 2,092

Alternative 1A +57,000 +21,000 +6 +6 No change +127

Alternative 1B +6,000 No change +6 +6 -0.15 +54

Alternative 2 +28,000 -24,000 No change No change No change +27

Alternative 3 +312,000 -260,000 +1 +1 No change +333

Alternative 4 -2,000 -9,000 -6 -6 No change -32

Alternative 5 No change -383,000 -26 -40 -0.85 -314

Alternative 6 +21,000 +20,000 +15 +1 -0.46 -34

Alternative 7 -115,000 No change No change -14 +0.73 -190

Alternatives That Would Reduce Dependence on the Reserve Component

Alternatives That Would Create New Types of Units

Premodular Force Structure

Alternatives That Would Increase the Size of the Army

Active

Personnel

Reserve

Personnel Support Ratioa

Costs or Savings

 (Billions of dollars)b

Supported

Combat Brigades

Total

Combat Brigades
SUMMARY xvii

Summary Table 3.

Continued

c. Assuming that the entire active force is committed.

d. CBO represented a corps as containing three divisions plus an armored cavalry regiment (10 combat brigades) and a theater as containing 

two such corps (20 combat brigades) and theater assets. Alternatives 5 and 7 use a smaller-sized force (60 percent of what the other 

alternatives use) to illustrate the potential qualitative benefits that proponents claim for those alternatives.

adding two divisions, with a total of six combat brigades, 

to the active component. CBO examined this option 

because it is a relatively common proposal in the public 

debate, especially among observers who worry that current missions are overstretching the Army.

One of the new divisions would be a heavy division, and 

the other would be a light division. Together, they would 

require a total of about 29,000 additional active personnel. This alternative would also add the full range of support units associated with two divisions (including corps 

support groups, corps artillery brigades, and so forth). 

Those support forces would include active and reserve 

units—preserving the Army’s current distribution of support units between the active and reserve components—

and would require another 12,000 active and 18,000 reserve personnel. In addition, this option would increase 

the number of personnel assigned to the Army’s administrative units and the size of its account for individuals not 

assigned to units by about 15,000 active and 3,000 reserve personnel to allow for the greater administrative 

workload and for an increase in the number of trainees, 

transients, and students. In all, those changes would require the Army to add about 78,000 personnel—57,000 

active and 21,000 reserve (see Summary Table 3).

Outfitting the new divisions with current equipment and 

continuing to modernize them thereafter would cost a 

total of $31 billion over the 2006-2022 period. Operating and supporting those units would cost another $95 

billion over that period and almost $7 billion a year after 

2022.

Creating two new divisions would give the Army more 

combat brigades for fighting wars and would improve its 

ability to sustain long deployments. If the additional divisions were structured like current forces, they would not 

be any easier or harder to deploy.

Increasing the size of the Army would not directly reduce 

the level of reserve mobilization needed to fight wars or 

sustain deployments, since the majority of the Army’s 

Current Force 138,000 90,000 20 53 102

Alternative 1A +14,000 +5,000 No change No change No change

Alternative 1B +12,000 +11,000 No change -6 -7

Alternative 2 +1,000 -22,000 No change No change No change

Alternative 3 +11,000 -32,000 No change No change No change

Alternative 4 +3,000 -2,000 No change No change No change

Alternative 5 -45,000 -69,000 No change -26 -49

Alternative 6 +12,000 +6,000 -7 -23 -46

Alternative 7 -32,000 -21,000 No change -24 -20

Premodular Force Structure

Alternatives That Would Increase the Size of the Army

Alternatives That Would Reduce Dependence on the Reserve Component

Alternatives That Would Create New Types of Units

Maxmium Number of

First Corps First Theater

Deployment Time (Days)d

Sustained Deployment

Reserve Mobilization for

 Sustained Deploymentc First Division

Personnel for
xviii OPTIONS FOR RESTRUCTURING THE ARMY

support units would remain in the reserves, and the active 

component would still need to mobilize those units for 

nearly all operations. Indirectly, however, a larger Army 

would be capable of maintaining a higher level of sustained deployments before it needed to mobilize reserve 

combat units to augment active forces. (Summary 

Table 3 shows an increase in reserve mobilization under 

this alternative because with a larger active force, the 

number of reserve personnel mobilized would rise if that 

entire force was committed to deployments.)

Alternative 1B—Add Two Active Divisions by Reducing 

Support Forces. Like the previous option, this alternative 

would add two divisions to the active component, but it 

would do so without appreciably increasing the overall 

size of the Army. Instead, it would make room for additional combat units by eliminating some support units 

from the Army’s current structure. CBO examined this 

alternative because some analysts have suggested that the 

Army has more support units than it needs and could 

shift personnel to more-useful combat units without 

unduly damaging its ability to wage wars.

This alternative would create room for two active 

divisions by eliminating all short-range air-defense 

(SHORAD) units and some corps-level artillery units 

from the Army’s force structure. CBO chose those support units for elimination because some observers have 

suggested they may not be necessary and because the 

Army has taken similar steps as part of its current reorganization plans. In addition, this option would do away 

with the logistical support units associated with the eliminated SHORAD and field artillery units, thus freeing up 

a total of 50,000 personnel to be used in the two new 

divisions. With fewer support units, divisions would be 

slightly smaller in this option than in the previous alternative. Even so, 50,000 troops would not be quite 

enough to fully staff the new divisions and their support 

units, so this option would require increasing the size of 

the active Army by 6,000 personnel (see Summary 

Table 3).

Outfitting the new divisions with current equipment and 

continuing to modernize them thereafter would cost 

slightly more than in Alternative 1A: a total of $34 billion 

through 2022.6 However, because this option would 

eliminate various support units, it would increase the 

Army’s operation and support costs to a far smaller extent 

than the previous option would: by $20 billion rather 

than $95 billion over the 2006-2022 period. After that, 

this alternative would add a little more than $1 billion 

annually to O&S costs, compared with nearly $7 billion 

under Alternative 1A.

Adding two divisions to the Army by reducing SHORAD 

and field artillery units would have almost the same advantages as simply increasing the size of the Army under 

the previous alternative. But it would carry some additional risks, since units would have less artillery support 

and no short-range air-defense capability. With slightly 

smaller divisions that would need fewer support units, 

this option would produce a smaller increase in the number of peacekeepers that the Army could deploy than 

would be the case in Alternative 1A. Deployment times 

would be faster, however.

Alternatives That Would Reduce Dependence 

on the Reserve Component

The next two approaches that CBO analyzed are intended to show how the Army could reduce its dependence on mobilizing reserve units to support active combat units. Both Alternatives 2 and 3 would effectively 

eliminate the need to deploy reserve units overseas to 

support active units in extended peacekeeping missions; 

Alternative 3 would also eliminate the need to deploy 

reserve units to support active units in major combat 

operations.

Implementing those alternatives, however, would not 

necessarily mean that no reserve personnel would be 

mobilized for peacekeeping or major combat operations, 

for two reasons. First, the Army’s overall capability to 

maintain extended deployments includes the personnel 

that would be available if the Army mobilized National 

Guard combat forces (and reserve support units for those 

combat forces). Presumably, the Army would generally 

attempt to carry out its missions by using active forces 

first, but some operations or combinations of operations 

could require enough troops that the Army would also 

mobilize National Guard combat forces—as it is now 

doing in Iraq. Using National Guard forces in that way 

would, of course, require mobilizing reserve personnel.

Second, the Army generally mobilizes some reserve personnel to fill in at the home bases of active units that have 

been deployed. That practice, known as “backfill,” allows 

6. Investment costs are higher for this option because CBO increased 

purchases of precision munitions to compensate for the reduction 

in artillery units.
SUMMARY xix

bases to keep functioning normally when their units are 

deployed (for example, reserve personnel might be called 

up to provide guards for the bases). Although the number 

of reserve personnel mobilized to provide backfill is 

smaller than the number of active personnel who have 

been deployed, that practice can still lead to a significant 

level of reserve mobilization if the active force is heavily 

committed.

Alternative 2—Reallocate Support Forces Between the 

Active and Reserve Components. Responding to criticism 

of the Army’s practice of relying on extensive and extended reserve mobilizations for peacekeeping missions 

and the occupation of Iraq, this option would shift support units between the active and reserve components. 

Units that are especially necessary for long peacekeeping 

operations (such as military police) would be moved from 

the reserve component to the active component, and 

units that are not essential for those operations (such as 

artillery units equipped with missile launchers) would be 

moved from the active Army to the reserves. As a result, 

virtually all of the support units needed for peacekeeping 

would be in the active component, and virtually all of the 

support units needed for warfighting would be in the 

reserve component.

All told, the number of personnel in combat and support 

units in the active Army would increase by 20,000 under 

this option, and the number of personnel in such units in 

the reserves would shrink by an equal amount. With individuals in administrative units, in training, or between 

assignments included, this alternative would increase the 

active Army by a total of 28,000 people and decrease the 

reserve component by 24,000 people (see Summary 

Table 3).

Those changes would greatly reduce the level of reserve 

mobilization necessary to conduct extended peacekeeping 

operations. The Army would still depend heavily on support units in the reserves for fighting wars and providing 

backfill for deployed active forces, but unless National 

Guard combat units were mobilized and deployed, peacekeeping operations would require far less sustained reserve mobilization in peacetime.

This option would not alter the Army’s investment costs 

over the 2006-2022 period because it would shift units 

rather than create or eliminate them. However, the increased number of active-duty personnel would raise 

operation and support costs by a total of $27 billion 

through 2022 and by $2 billion per year thereafter.

Reallocating the Army’s support forces between the active 

and reserve components would not affect the service’s 

ability to fight wars because the Army would still have 

access to all of the combat divisions and support units 

that it has now. Similarly, such a reallocation would have 

only a minimal effect on the Army’s ability to support 

long deployments.

This alternative would not affect deployment times directly, since the same equipment would have to be transported whether a particular unit was in the active or reserve component. This option might affect deployment 

times indirectly, however, because many types of support 

units (such as artillery units with missile launchers) 

would exist only in the reserves, and reserve units typically require at least a month for mobilization. However, 

that situation also exists for some types of units, such as 

civil affairs units, under the Army’s current structure. 

Alternative 3—Eliminate the Army’s Dependence on Reserve Support Units by Increasing the Size of the Active 

Component. This option would eliminate the Army’s 

reliance on support units in the reserve component by 

adding enough personnel to the active Army to create 

support units for all 10 of its divisions. The option is 

included in this analysis because it illustrates the full cost 

associated with ending the Army’s current dependence on 

the reserves to support major deployments.

Besides creating new support units in the active component, this alternative would turn one of the Army’s four 

corps, which is now composed almost entirely of reserve 

units, into a fully active corps; provide an active armored 

cavalry regiment (ACR) for each corps; and shift all of the 

Army’s reserve special forces groups into the active component. To create the full set of support units needed for 

the four corps, 10 divisions, and 35 combat brigades that 

would be in the active Army under this alternative, an 

additional 312,000 personnel would be necessary. The 

reserve component could shrink by 260,000 personnel 

because it would no longer have to support active combat 

forces (see Summary Table 3).

The Army’s investment costs would not change under 

this option because, for all of the support units created in 

the active component, identical units would be eliminated from the reserves. However, this option would have 
xx OPTIONS FOR RESTRUCTURING THE ARMY

a larger impact on operation and support costs than any 

other alternative that CBO examined, increasing those 

costs by a total of $333 billion through 2022 and by 

about $26 billion per year thereafter.

Increasing the size of the active Army to a level that 

would eliminate its dependence on reserve support units 

would not significantly affect the service’s ability to fight 

wars, since the Army would have almost the same type 

and number of combat formations as it does now. That 

change would, however, improve the Army’s ability to 

sustain peacekeeping operations. The number of soldiers 

the Army can keep on extended deployment is limited by 

the fact that, according to DoD policy, reserve personnel 

cannot be deployed as frequently as active personnel. In 

this option, transferring a corps, the ACRs, and the special forces groups to the active component would allow 

those units to rotate through deployments at the higher 

rate used for active personnel rather than the lower rate 

used for reserve personnel.

The main benefit of this alternative is that the Army 

would not need to deploy reserve units overseas for major 

combat operations or long deployments. Reserve personnel would still need to be mobilized to provide backfill 

for active forces that were deployed, but no reservists 

would need to be deployed themselves. In the case of a 

very large peacekeeping deployment—larger than the active Army’s forces could sustain alone—the Army might 

need to mobilize and deploy National Guard combat 

troops (and support forces for those combat troops). But 

for any level of commitment less than that, reserve units 

would not need to be sent overseas.

Since this option would not alter the types of units in the 

Army, it would not directly change deployment times. 

However, because reserve units typically require at least a 

month for mobilization, the Army might be able to deploy faster in some circumstances since it would not have 

to wait for reserve units to mobilize.

A potential variation on this option would be to eliminate enough active combat forces that the active Army 

would have sufficient personnel to support all of its combat units—in other words, to hold the size of the active 

component constant rather than hold the number of active combat units constant, as in this option. Doing that 

would require the Army to cut a corps, four divisions, 

and an ACR from the active component. Although that 

change would eliminate the active Army’s dependence on 

the reserves in the same way that increasing the size of the 

Army would, it would substantially reduce the number of 

forces available for warfighting and extended deployments.

Alternatives That Would Create New Types of Units

The rest of the options in this analysis would restructure 

the Army in ways that emphasize different types of units, 

in response to a variety of concerns and proposals. Alternative 4 reflects a proposal by the National Defense University to create special “stabilization and reconstruction” 

divisions dedicated to peacekeeping. Alternative 5 would 

implement the frequently cited ideas of retired Army 

Colonel Douglas MacGregor, who has proposed converting the Army into flexible, autonomous brigade-sized 

combat groups. Alternative 6 would improve deployment 

speed by changing the Army’s organization to more 

closely resemble that of the Marine Corps. Finally, Alternative 7 reflects the ideas of some leading proponents of 

“military transformation” in an attempt to show, in concrete detail, what a transformational force might look 

like.

Alternative 4—Organize Stabilization and Reconstruction Divisions. Many observers have argued that the 

Army should improve its peacekeeping capabilities relative to its warfighting capabilities. In keeping with those 

arguments, this option would convert some of the Army’s 

combat divisions into dedicated peacekeeping divisions, 

or what a study by the National Defense University calls 

stabilization and reconstruction (S&R) divisions.7

In this alternative, the Army would eliminate two active 

combat divisions (one heavy division and one light infantry division) along with their associated support units. It 

would use the personnel freed up to organize five S&R 

divisions, four in the active component and one in the reserve component. Those S&R divisions would include 

military police, engineer, medical, civil affairs, and psychological operations units—which have been in great 

demand for peacekeeping operations—as well as a single 

medium-weight Stryker brigade. Overall, the number of 

personnel freed up by eliminating the combat divisions 

and their support units would be larger than the S&R 

divisions would require, which means that the Army 

7. Hans Binnendijk and Stuart Johnson, eds., Transforming for Stabilization and Reconstruction Operations (National Defense University, Center for Technology and National Security Policy, November 12, 2003).
SUMMARY xxi

would need 2,000 fewer active personnel and 9,000 fewer 

reserve personnel (see Summary Table 3).

Those changes would decrease the Army’s total investment costs by almost $14 billion over the 2006-2022 

period—both because of the smaller number of combat 

divisions that the Army would need to modernize and 

because of a reduced emphasis on high-technology weapons intended for conventional warfighting. The changes 

would also save $18 billion in operation and support 

costs through 2022 and $1 billion annually thereafter.

This alternative would reduce the Army’s ability to fight 

wars because the service would have six fewer combat brigades available for contingency operations. In addition, 

the option would yield only a small increase in the total 

number of personnel that the Army could sustain on extended deployments, because the number of soldiers in 

the new S&R divisions would be roughly the same as the 

number in forces used for peacekeeping operations today. 

(The small increase would result from converting some 

units that are intended to support high-intensity combat 

to units better suited for peacekeeping.) Qualitatively, the 

mix of soldiers in each S&R division might be superior to 

the Army’s current combat forces for peacekeeping, given 

their specialties and the historical demand for those types 

of units in peacekeeping missions. But CBO is unable to 

assess that potential superiority quantitatively. 

This option would yield a slight decline in the level of 

reserve mobilization needed to sustain extended deployments because each active S&R division could be deployed without the reserve support units associated with 

combat divisions. That reduction would be lessened, 

however, if the Army needed to mobilize and deploy the 

S&R division in the reserve component.

Since S&R divisions are not intended for major combat 

operations, they would most likely not be deployed to 

fight a war. Thus, their creation would not affect the 

speed with which the Army could deploy its combat 

forces.

Alternative 5—Convert to a Brigade-Based Army. This 

option would restructure the Army in the manner suggested by retired Army Colonel Douglas MacGregor: 

eliminating higher-level command structures and organizing the Army’s forces into a number of autonomous 

brigade-sized combat groups.8

 Some elements of MacGregor’s proposals are similar to the Army’s currently 

planned modularity reorganization.

This option would eliminate divisions, corps, and theaters (and the traditional support structures associated 

with them) and create a set of large, semiautonomous 

brigade-sized combat groups in the active component. As 

in MacGregor’s proposals, it would create a total of 25 

combat groups in the active force and four in the reserves. 

The traditional forms of support provided by higherechelon units would instead be provided by a mix of support groups, including aviation, artillery, air-and-missiledefense, surveillance, reconnaissance, engineering, logistics, and other types of units. This option would reduce 

the total number of combat brigades available to the 

Army from 69 to 29, but all of them would be fully supported.9 Most of that reduction would come from eliminating almost all of the National Guard’s combat forces.

This alternative was constructed to adhere as closely as 

possible to MacGregor’s plan for restructuring the Army; 

as such, it differs from most of the other alternatives that 

CBO analyzed. It is the only option that does not use the 

Army’s rules for allocating support units, does not include 

a theater level of command, and does not include significant combat forces in the reserve component. This alternative would not change the number of active personnel 

but would require 383,000 fewer reserve personnel (see 

Summary Table 3). 

In keeping with MacGregor’s intent to improve the combat power of heavy forces as they are now equipped, this 

option would significantly alter the Army’s investment 

plans. It would terminate the Future Combat Systems 

program (which is intended to replace current heavy platforms) while continuing various initiatives to rebuild, 

remanufacture, and upgrade the Army’s heavy equipment. Those changes, combined with the smaller number 

8. See Douglas A. MacGregor, Breaking the Phalanx: A New Design 

for Landpower in the 21st Century (Westport, Conn.: Praeger Publishers, 1997), and Transformation Under Fire: Revolutionizing 

How America Fights (Westport, Conn.: Praeger Publishers, 2003). 

Alternative 5 addresses only a small subset of the reforms that 

MacGregor has proposed. In particular, CBO’s analysis does not 

evaluate the changes in Army warfighting doctrine, culture, or 

personnel policies that MacGregor believes would be at least as 

important as—if not much more important than—the organizational changes discussed in this analysis.

9. In addition, all of the combat brigades in the active component 

would be supported by active support units.
xxii OPTIONS FOR RESTRUCTURING THE ARMY

of brigades that would need to be modernized under this 

option, would decrease the Army’s investment costs by a 

total of $176 billion through 2022. They would also save 

$138 billion in O&S costs over the projection period and 

$10 billion per year thereafter.

By reducing the number of combat troops in the Army 

and emphasizing support units that would not be useful 

in peacekeeping (such as aviation or artillery strike 

groups), this option would leave the Army much less able 

to sustain extended deployments. However, because those 

combat troops would not depend on reserve support 

units, the forces that the active Army could sustain in 

peacekeeping operations would not require significant 

levels of reserve mobilization.

MacGregor suggests that an Army with only 25 active 

combat brigades, structured as he proposes, would be 

better able than the current force to deploy quickly and 

engage in fast-moving operations that would overwhelm 

conventional enemies. Based on CBO’s assumptions 

about what a corps- or theater-sized force would look like 

in an Army modeled on MacGregor’s concepts, this alternative would improve deployment times by more than 

one-and-a-half months (from three-and-a-half months to 

less than two months) for a theater-sized force. That improvement would be achieved both by the smaller force 

that would be deployed (just 60 percent of the brigades 

used for current forces) and by the reduced number of 

support units associated with each combat group (compared with an equivalently sized force composed of current units).

That improvement, however, would occur only if it 

proved feasible to engage in sustained combat operations 

with substantially lower levels of support than are used in 

today’s Army. The improvement would also depend on 

the feasibility of eliminating the theater level of command, which performs a number of functions (such as 

seaport operations) that are important to other services 

operating in a theater. In that case, the other services 

might need to increase the size of their forces to compensate for the lack of support from the Army.

Because this alternative would greatly reduce the need for 

personnel in the reserve component, a number of variations on this option could be constructed that would restore the theater level of command or permit a larger 

number of National Guard combat units. Making such 

changes would reduce the savings from this option as well 

as some of the improvement in deployment speed, but it 

would increase the Army’s overall ability to fight wars and 

sustain extended deployments.

Alternative 6—Convert to an Expeditionary Army. This 

alternative illustrates how the Army might be able to 

improve its deployment speed by adopting some organizational structures and practices used by the Marine 

Corps. This option would eliminate the corps as a command structure, reorganize the Army into a series of expeditionary forces (similar to Marine expeditionary forces), 

and purchase more sealift ships as well as additional sets 

of equipment that would be prepositioned on ships near 

potential areas of conflict.

In this alternative, each Army expeditionary force would 

consist of a division with four combat brigades (as currently sized and structured), an expanded aviation group, 

and a support group with logistics, communications, and 

other support units.10 Each expeditionary force would 

have one more combat brigade and slightly more personnel than a current division and its full set of combat and 

support units (43,000 people versus 39,000). In this option, the active Army would contain five heavy expeditionary forces and four light expeditionary forces. The 

reserve component would have four heavy and two light 

expeditionary forces and would retain 10 of the National 

Guard’s current separate brigades. This option would also 

provide a full set of support units for all National Guard 

combat forces. In total, those changes would require 

21,000 additional active personnel and 20,000 additional 

reserve personnel (see Summary Table 3).

To provide more sealift and prepositioned equipment, 

CBO developed a very different investment program for 

this alternative than the Army currently envisions. This 

option would terminate the Future Combat Systems program (which has been developed, in part, to improve 

deployment speed) and would replace it with various programs to rebuild, remanufacture, and upgrade the Army’s 

current heavy equipment. The resulting investment program would be more expensive than the one in the previous alternative, both because this option would result in a 

larger heavy force and because it would have the Army 

10. Marine Corps divisions do not have four subordinate combat brigades, but maneuver units make up a larger share of a Marine division than they do of an Army division. For this alternative, CBO 

approximated that difference by adding a fourth brigade to each 

division.
SUMMARY xxiii

procure several additional sets of equipment to preposition on ships. The Army would also buy 20 more large, 

medium-speed roll-on/roll-off ships (LMSRs) to transport equipment and to establish new flotillas of prepositioned equipment in the Mediterranean Sea and the 

Pacific Ocean.

This option would decrease the Army’s investment costs 

by $87 billion over the 2006-2022 period, primarily from 

ending the FCS program. It would add $9 billion to the 

costs of the National Defense Sealift Fund, for a net savings of $79 billion over the projection period. This alternative would also increase O&S costs by a total of $45 

billion through 2022 and by just over $3 billion annually 

after that period.

Converting to an expeditionary Army would produce a 

small positive change in the number of brigades available 

to the Army for fighting wars. It would increase the total 

number of combat brigades available by one, but it would 

better support the remaining National Guard combat formations, thus raising the number of fully supported combat brigades by 15. This option would also improve the 

Army’s ability to sustain extended deployments and 

would slightly change the level of reserve mobilization 

needed to support those deployments.

The major advantage of switching to an expeditionary 

Army is that it would greatly reduce deployment times 

for large forces, such as a corps or theater. At the theater 

level, deployment times would decline from the current 

three-and-a-half months to less than two months. That 

improvement would result from the increased number of 

LMSRs, the additional flotillas of prepositioned materiel 

(which arrive in a theater sooner than materiel from the 

continental United States would), the reduced levels of 

support units, and the elimination of units associated 

with the corps. That last effect is relevant because deploying a corps to support and control multiple divisions requires about as much lift as each division does. For that 

reason, deploying three expeditionary forces (with 12 

combat brigades) would actually require less lift than a 

current corps (with 10 combat brigades) does.

Alternative 7—Convert to a Transformational Army. The 

final alternative that CBO analyzed attempts to illustrate 

the type of force that many defense experts, such as 

DoD’s former Director of Force Transformation, Arthur 

Cebrowski, have suggested would be “transformational”—that is, would take full advantage of recent 

advances in communications networks, precision-guided 

munitions, and sensors. Such experts typically stress the 

virtues of small, light ground formations that can be deployed rapidly and that depend on long-range, precision 

firepower instead of their own weaponry for effectiveness.

Under this alternative, the Army would have fewer divisions (although the corps structure would remain), and 

the mix of divisions would be shifted to lighter forces and 

special forces groups. Specifically, the active Army would 

consist of two heavy, two air assault, and two light infantry divisions. The National Guard would have a similar 

structure, with four heavy and two light infantry divisions (as well as its current separate brigades). Each division would receive significantly more attack and reconnaissance helicopters, cannon artillery, and missilelauncher artillery than current divisions have. In addition, some support units would be shifted between the 

active and reserve components. Overall, that restructured 

force would require 115,000 fewer active personnel than 

the Army currently has (see Summary Table 3).

Even with the emphasis on high-technology weapons, 

this option would lower the Army’s investment costs by a 

total of $24 billion through 2022 because of the reduced 

number of combat divisions that the Army would need to 

modernize. In addition, that smaller force would cost 

$166 billion less to operate and support over the 2006-

2022 period than the currently planned force and $12 

billion less per year thereafter.

Supporters of military transformation argue that for a 

combat force equipped with modern communications, 

sensors, and precision munitions, size is not a good measure of fighting ability. In their view, military capability is 

more closely related to the ability of a force to identify 

and destroy targets (requiring superior intelligence and 

precision) than to the overall size of the force. Some supporters would even argue that smaller forces may be superior to larger forces because they are faster to deploy, 

more capable of surprising the enemy, and better able to 

disperse. This option would reduce the total number of 

available combat brigades by 14 (or about 20 percent), 

but if supporters’ claims for improved warfighting ability 

are true, the Army might be capable of engaging in more 

simultaneous conflicts. However, CBO cannot assess 

such claims about the qualitative improvement that a 

transformational Army might provide.
xxiv OPTIONS FOR RESTRUCTURING THE ARMY

Since the overall Army would be much smaller under this 

option than it is today, its ability to keep large numbers of 

personnel deployed for extended peacekeeping operations 

would be significantly reduced—by about 32,000 personnel—for two reasons. First, a smaller force cannot 

keep the same levels of personnel deployed as a larger 

force. Second, this option emphasizes long-range firepower, which is generally not useful for peacekeeping 

operations, so a smaller percentage of the Army’s total 

support units would be suited to peacekeeping. 

This option would not alter the degree to which the 

active Army relies on reserve units for support, so it 

would not change the level of reserve mobilization 

needed to sustain any given level of extended deployment 

(although if the Army was fully committed, reserve mobilization would rise). Since the Army would be smaller in 

this alternative, however, it would be more likely to need 

to mobilize and deploy National Guard combat units to 

sustain peacekeeping operations.

Supporters of military transformation claim that because 

a transformational Army would be able to fight wars with 

fewer but more-capable forces, it would be able to deploy 

to operations more quickly. CBO assessed that claim by 

assuming that corps- or theater-sized forces would be 40 

percent smaller in this option than they are today. In that 

case, deployment times would decline by about 20 percent (or almost three weeks) for a theater-sized force. The 

reduction in deployment time is not as large as the reduction in size because with the emphasis on long-range firepower, each division would actually require more support 

units than the current force does. Artillery units, in particular, require significant logistical support, so the focus 

on long-range firepower in this option largely offsets the 

benefits of a smaller force. As a result, a theater-sized 

force that had 60 percent of the combat brigades used for 

current forces would require about 70 percent of the lift 

needed for current forces.
1

The Army’s Current and Planned Structure

The Army is responsible for providing the majority 

of the land forces needed to carry out U.S. national security strategy. The Army’s current structure was largely determined by reactions to the end of the Cold War as well 

as policy decisions made during the downsizing of the 

military that occurred in the early to mid-1990s. However, the Administration has substantially altered the U.S. 

national security strategy since 2001 and has entered into 

several military operations associated with the war on terrorism. Taken together, the largest of those operations, 

Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq, have required the Army to 

engage in a higher level of overseas commitment than was 

envisioned during the 1990s.

The Army’s current level of overseas commitment and the 

resulting stresses imposed on a force not explicitly designed to perform such missions have given rise to debate 

about how large the Army should be and how it should 

be structured. The number and type of units in the Army, 

the types of equipment those units use, and the allocation 

of units between the active and reserve components of the 

Army all affect the service’s capability to perform different types of missions in the current national security environment.

In this analysis, the Congressional Budget Office (CBO) 

developed measures of the Army’s capability to perform 

several types of missions and explored various options for 

changing the Army’s structure to improve its performance 

in certain areas. Those options illustrate how different elements of the Army’s structure are connected and affect 

one another, as well as the costs and trade-offs associated 

with proposals for restructuring the Army.

The Army’s Force Structure

Prior to Modularity

The Army can be divided broadly into deployable and 

nondeployable units. Deployable units can be further 

divided into combat units and support units. There also 

are important differences in the ways the Army structures 

and uses its active and reserve components.

This section describes the Army as it was organized at the 

beginning of 2004. The Army’s structure is continually 

changing, and several major initiatives have been announced since then, the most important of which would 

involve an extensive restructuring effort to convert the 

Army to a set of “modular” combat and support brigades. 

However, those initiatives have not yet been incorporated 

into the Department of Defense’s (DoD’s) detailed budget plans, and as such, CBO is not able to fully assess 

their effects.1

Nondeployable Units

The Army’s nondeployable units, referred to as Table of 

Distribution and Allowances (TDA) units, are generally 

administrative or overhead organizations responsible for 

manning, training, and equipping the Army’s forces. 

Examples include the Human Resources Command, 

Training and Doctrine Command, and Army Materiel 

Command. The majority of TDA units are in the active 

component of the Army, although both the Army Reserve 

and Army National Guard have TDA elements. Reservecomponent TDA units are largely manned with Active Guard/Reserve personnel (“full-time” reservecomponent personnel). In this study, TDA units are 

referred to as administrative units.

CHAPTER

1. Although the Army has begun implementing the changes associated with modularity, for convenience, CBO sometimes refers to 

the premodular force as the current force in this study.
2 OPTIONS FOR RESTRUCTURING THE ARMY

The Army also maintains a pool of individual soldiers 

who are, for a variety of reasons, not assigned to any unit 

(and are not deployable). That pool, referred to as the 

trainees, transients, holdees, and students (TTHS) account, includes soldiers who are in basic or advanced 

training, in schools, moving between assignments, or in 

other situations that do not permit them to be assigned to 

a unit. Currently, only the active component of the Army 

has a TTHS account. In this study, TTHS personnel are 

referred to as individuals.

Deployable Units

The remainder (and majority) of the Army’s personnel 

are in deployable units, referred to as Table of Organization and Equipment (TOE) units. TOE units are organized according to a template—a TOE document—that 

establishes the type of personnel and equipment for each 

type of unit.2 The Army has several hundred different 

types of units, varying greatly in size and type. The two 

primary classes of TOE units are the major combat units 

(divisions, separate brigades, and armored cavalry regiments, or ACRs) and support units assigned to higher 

command echelons (corps- and theater-level support 

units).

The major combat units include several types of forces. 

The Army distinguishes between maneuver units such as 

armor or infantry—which can close with and destroy the 

enemy—and all other units, which are intended, directly 

or indirectly, to support maneuver units.3

 The major 

combat units are differentiated by their maneuver units, 

which largely determine the types of support that the 

combat units need. “Heavy” units—based on mechanized 

infantry and armor units—are equipped with tanks and 

other armored vehicles and are intended for combat in 

relatively open terrain against other armored forces. 

“Light” units—based on light infantry, airborne, or air 

assault units—are various types of units without armored 

vehicles and are intended for combat in more complex 

terrain (urban areas, jungles, or mountains) against enemies with only limited armored forces. “Medium” units 

—equipped with the Army’s new Stryker light armored 

vehicle—are relatively new and are intended to be more 

easily deployed than heavy forces but more lethal than 

light forces.

Some types of support units are directly associated with 

particular types of combat units. Heavy forces, for example, receive self-propelled howitzer battalions and 

tracked-rocket-launcher battalions for artillery support, 

whereas light forces receive towed howitzer battalions and 

wheeled-rocket-launcher battalions for artillery support. 

Other types of support units are associated with the different demands of the various combat units—heavy 

forces simply require more fuel-transport, ammunitiontransport, and maintenance units. Still other kinds of 

support units are essentially common to all types of combat units—for example, heavy and light forces require the 

same numbers of legal services teams or water purification units. Overall, the support package associated with 

heavy units is somewhat larger (in terms of number of 

personnel) and heavier (in terms of the weight of its 

equipment) than the support package associated with 

light units.

Components

The Army’s components are the active Army and the 

reserves, which include the Army Reserve and the Army 

National Guard.4 All three are integrated together in accordance with DoD’s Total Force Policy in a manner that 

is sometimes referred to as the Abrams Doctrine (after 

former Chief of Staff of the Army Creighton Abrams, its 

major proponent). The core of that integration is the idea 

that the active Army’s major combat units should be 

heavily dependent on reserve support units.

The Army has implemented the Total Force Policy by 

concentrating combat units in the active component and 

support units in the reserves. Consistent with that policy, 

the active Army’s deployable forces are primarily major 

combat units, whereas the Army Reserve is entirely organized to support active units and does not include any 

major combat units. The Army National Guard includes 

both combat and support forces, although some of those 

combat forces do not have support units associated with 

2. The Army sometimes makes a distinction between TOE documents, which are templates for actual units, and actual units, 

which almost always vary somewhat from the templates. When 

making that distinction, the Army refers to actual units as modified TOE (MTOE) units.

3. The distinction between maneuver and support units is not the 

same as the distinction between combat-arms, combat-support, 

and combat-service-support units. CBO did not employ the latter 

distinction in this study, although it is a common way of discussing Army units.

4. Collectively, the entire Army is sometimes referred to as the “total 

Army” to avoid confusion stemming from the common practice of 

referring to only the active component as “the Army.”
CHAPTER ONE THE ARMY’S CURRENT AND PLANNED STRUCTURE 3

them and most likely would not be deployed to major 

combat operations. Overall, about two-thirds of the 

Army’s supported combat brigades are in the active component, and about two-thirds of the Army’s support units 

are in the reserves. Different types of support units, however, are more or less concentrated in one component or 

the other. More than 95 percent of the Army’s civil affairs 

units, for example, are reserve units.

The overall effect of the division of responsibility between 

the Army’s components is that active Army combat formations are heavily dependent on reserve support; thus, it 

is extremely difficult for the Army to engage in any major 

operation without mobilizing reserve personnel. The policy establishing that structure was adopted in the mid1970s, when many Army leaders and defense policymakers believed that one of the causes of the failure of the 

U.S. effort in Vietnam was the loss of public support. In 

their view, the decision by political leaders not to mobilize large numbers of reserve personnel for the Vietnam 

War—a higher level of commitment than deploying 

active forces—showed that they were unwilling to take 

actions that would strongly commit the United States to 

the war. According to that line of thought, if reserves had 

to be mobilized for any future conflict, political leaders 

would either be less likely to engage the United States in 

conflicts that would not command broad public support 

or would be more likely to ensure that public opinion was 

fully mobilized and in support of any future major military operation.

How Army Units Are Used in the Field

Army units are generally organized so that each combat 

unit has three major subordinate combat units and a mix 

of subordinate support units (see Box 1-1). As such, any 

combat unit larger than a company will include some 

subordinate support units. However, it is convenient, for 

a variety of reasons, to differentiate between the support 

units included in the major combat units (divisions, separate brigades, and ACRs) and the support units included 

in higher-echelon commands (corps and theaters).

Prior to the changes associated with modularity, divisions—which typically have about 15,000 personnel and 

three subordinate combat brigades—were organized for 

combat into three brigade combat teams (BCTs) by using 

units from support brigades in the division to reinforce 

the division’s combat brigades. The remaining divisional 

support units are sometimes referred to as the “division 

base” (including all of the division’s aviation assets). Separate brigades and ACRs are always organized as BCTs 

with all of their support units. All BCTs (divisional, separate, and ACR) of a given type—light, medium, and 

heavy—are essentially identical in size and combat power. 

(See Appendix A for more details on the composition of 

the major combat units.)

Corps- and theater-level support units—referred to as 

echelons-above-division (EAD) units—provide either 

direct or general support to the major combat units.5

Such support varies from augmenting the firepower of 

major combat units with attack helicopters or artillery 

to providing capabilities that major combat units do not 

include (such as civil affairs or construction engineering), 

as well as medical and logistics support that is very limited in major combat units. 

Except in the smallest and most limited operations, the 

Army’s major combat formations are not capable of engaging in sustained military operations without EAD 

support units. Any time the Army deploys combat forces 

to a major operation, it must also deploy a corresponding 

package of support units. The Army has doctrinal rules 

for what those support packages should include and designs its force structure in accord with those rules.6 In 

actual operations, the Army will tailor the specific mix of 

support units on the basis of the theater and mission, but 

when designing its force, the Army assumes that those 

rules describe a typical force package. Thus, it is possible 

to determine what units and how many personnel the 

Army assumes will be needed to support each type of 

combat brigade or division (about 15,000 support personnel per division), as well as the size of the “fixed-cost” 

support package associated with deploying a corps (about 

25,000 support personnel) or a theater (about 35,000

5. Theater-level units are sometimes referred to as echelons-abovecorps units. The major difference between a corps and a theater is 

that the theater provides certain strategic forms of support (such 

as operating port facilities or strategic communications) that benefit a wide range of units, whereas the corps provides more-direct 

support to the major combat units. (See Appendix A for more 

details about the types of support units associated with the corps 

and theater.) The theater also provides support to other services, 

including detention of enemy prisoners of war, intratheater water 

transportation, and port management.

6. That practice is the heart of the Army’s biennial Total Army Analysis process. See U.S. Army War College, How the Army Runs: 

A Senior Leader Reference Handbook, 2003-2004 (Carlisle, Pa., 

2003). 
4 OPTIONS FOR RESTRUCTURING THE ARMY

support personnel). Given that the Army deploys a corps 

for every two to five divisions and a theater for every one 

to two corps, a large force will deploy about 40,000 to 

45,000 personnel for each division. Those numbers 

match well with the Army’s actual practices, since the 

Army deploys an average of a bit more than 40,000 personnel for every division it deploys.7

Concerns with the Premodular

Structure

A wide variety of defense analysts, Administration officials, and policymakers have expressed concerns about the 

Army’s current size, structure, and ability to perform its 

missions. Those concerns focus on, among other things, 

the Army’s capability to support extended deployments or 

to engage in multiple major combat operations, the need 

to rely on reserve units, and the time it takes to deploy 

Army units to distant theaters.

Box 1-1.

Army Command Levels

Squad/Section: The smallest tactical unit. A squad is 

commanded by a sergeant and has about eight to 15 

personnel (or two vehicles, in the case of a section).

Platoon: The basic tactical unit of a company. A platoon is commanded by a lieutenant and includes 

varying numbers of subordinate squads or sections. It 

has about 16 to 50 personnel. Heavy platoons have 

four armored vehicles.

Company/Troop/Battery: The basic tactical unit of a 

battalion. A company is commanded by a captain 

and includes two to five subordinate platoons (usually three or four). It has about 60 to 200 personnel. 

Heavy companies have 14 armored vehicles. Cavalry 

companies are called troops; artillery companies are 

called batteries.

Battalion/Squadron: The smallest tactically independent unit in the Army. A battalion is commanded by 

a lieutenant colonel and includes two to five combat 

companies (usually three or four) and, depending on 

the type, some support companies. It has about 400 

to 800 personnel. Heavy battalions have 44 to 58

armored vehicles. Cavalry battalions are called squadrons.

Brigade/Regiment/Group: Brigades can be either separate or subordinate to a division. A separate brigade 

is commanded by a brigadier general, whereas a divisional brigade is commanded by a colonel. Both include two to five combat battalions (usually three). 

Brigade combat teams (BCTs) are combat brigades 

that have been tactically organized to include an artillery battalion, an engineer battalion, and a logistics 

battalion. Brigades have about 2,000 to 3,500 personnel, and BCTs have about 2,500 to 5,000 personnel. Cavalry brigades are called regiments. Some 

types of support brigades are called groups.

Division: The primary tactical unit in the Army. A 

division is commanded by a major general and includes two to five combat brigades (usually three), an 

aviation brigade, an artillery brigade, an engineer brigade, and a logistics brigade. Divisions may also 

command separate brigades. Divisions have about 

12,000 to 16,000 personnel.

Corps: The largest tactical unit in the Army. A corps 

is commanded by a lieutenant general and includes 

two to five divisions, an armored cavalry regiment, 

and numerous support brigades and commands. 

Corps may also command separate brigades. Corps 

have about 80,000 to 200,000 personnel.

Theater: The highest command level in the Army. It 

is an element of the joint command structure, with a 

general as the Army service component commander. 

A theater is established to support one or more corps 

(usually two) and includes numerous support brigades and support commands. It has no standard 

number of personnel.

7. That average, also referred to as the “division slice,” has been very 

stable since the Army began using modern divisions in the early 

20th century.
CHAPTER ONE THE ARMY’S CURRENT AND PLANNED STRUCTURE 5

Capability to Sustain Extended Deployments

The occupation of Iraq has required the Army to sustain 

a large occupation force there, potentially for an indefinite period. In addition, the Army has other commitments—including in Afghanistan, the Balkans, and 

South Korea—that it must sustain. Whether the Army is 

able to meet all of those commitments and remain capable of responding to other contingencies that might arise 

has been a subject of debate.

Concerns that the Army’s forces in Iraq are too small have 

been raised persistently in public debate. However, as it is 

currently sized and structured, the Army is not capable of 

indefinitely sustaining a larger force in Iraq while maintaining high levels of readiness and quality of life for soldiers.8 Many advocates of a larger occupation force believe that the Army should be made larger to allow for a 

greater pool of forces to draw upon.

Other advocates of a larger Army believe that the United 

States is likely to need to engage in extensive stabilization 

and reconstruction missions after most future conflicts. 

In that view, a larger force would allow the United States 

either to engage in more such missions concurrently or 

perform such missions without placing as much stress on 

personnel, equipment, and units. In particular, such advocates argue that the need to maintain the Iraq occupation force is putting unacceptable levels of stress on the 

Army and may lead to serious problems with recruiting, 

retention, or readiness.

Some observers argue that the peacekeeping missions 

associated with extended deployments do not so much 

require more forces as they do forces that are designed for 

peacekeeping as a primary mission. The vast majority of 

Army forces are primarily intended for high-intensity 

combat, although the Army views them as capable of performing peacekeeping missions when needed. Several 

public proposals have called for some form of dedicated 

peacekeeping force, with proponents claiming that such 

force would be qualitatively better than conventional 

combat forces.

Capability to Engage in Major Combat Operations

Prior to the invasion of Iraq, there was significant public 

debate about whether U.S. forces could engage in two 

major combat operations simultaneously or nearly simultaneously. DoD’s 2001 Quadrennial Defense Review 

(QDR) renounced the 1990s-era “two major theater war” 

strategy but did require U.S. forces to be capable of 

simultaneously “swiftly defeating enemy attacks” in two 

theaters. However, because almost all Army forces are 

currently deployed, preparing to deploy, or recovering 

from deployment, there has been substantial debate 

about how capable the United States would be of 

responding should any new contingency arise.

Numerous defense analysts and Members of Congress 

have expressed the belief that the Army would not currently be capable of fully responding to any new contingency (for example, should the United States become engaged in military operations against Iran or North Korea) 

and that the size of the Army should be increased as a result. Other analysts would argue that the ability to simultaneously engage in at least two major combat operations 

is a desirable goal that would contribute to deterring 

potential U.S. adversaries. The 2001 QDR strategy does 

appear to commit DoD to a formal goal of being able to 

fight two major combat operations while maintaining 

other commitments.

However, other defense experts argue that maintaining 

sufficient ground forces to conduct multiple major combat operations, as traditionally understood, might not be 

necessary or desirable. Some of those experts argue that 

air power or naval power can substitute for ground forces. 

Others contend that in the event of a major combat operation, the United States should simply prioritize among 

commitments—perhaps pulling forces out of lowerpriority commitments to fight a major combat operation. 

Finally, some defense experts believe that recent technological developments in computers, communications, 

and networking have allowed the United States to transform the way it fights wars, enabling very small U.S. 

forces to defeat even relatively large and formidable opponents. That view holds that a small force equipped with 

advanced communications networks and access to longrange, precision-guided weapons would be more capable 

than a larger force because it could move and react more 

rapidly.

One element of the Army’s structure that particularly 

affects its ability to fight wars is that the Army National 

Guard has maintained two classes of units over the past 

decade. The National Guard’s separate brigades are kept 

at a relatively high level of manning and readiness, are 

included in operational plans for conflicts, and are being 

8. See Congressional Budget Office, An Analysis of the U.S. Military’s 

Ability to Sustain an Occupation of Iraq (September 2003).
6 OPTIONS FOR RESTRUCTURING THE ARMY

deployed to Afghanistan and Iraq. The National Guard’s 

divisions, by contrast, are maintained at relatively low levels of manning and readiness, are not included in operational plans for conflicts, and have only been deployed to 

lower-intensity missions, such as those in Bosnia, Kosovo, 

or the Sinai.

In accordance with the low priority that the Army has 

placed on National Guard divisions, many of those divisions’ subordinate brigades are unsupported (in other 

words, the Army lacks sufficient support units to deploy 

those brigades to combat operations). Not all observers 

regard that situation as problematic, and the Army has 

frequently described the National Guard divisions as having missions (such as providing homeland security or a 

strategic reserve) that suggest they might not need a full 

set of support units. However, other observers argue that 

those unsupported divisions represent deadweight in the 

Army’s force structure since they cannot be deployed 

overseas or participate in the full range of Army missions.9

 Each unsupported division would require about 

15,000 personnel in EAD support units. CBO estimates 

that between four and six of the National Guard divisions 

are unsupported, suggesting that the Army would need 

an additional 60,000 to 90,000 personnel to fully support those divisions.

Use of the Reserve Component

Military operations associated with the war on terrorism 

have required the Army to mobilize more reserve personnel, and keep them mobilized, than the modern allvolunteer force has ever experienced before. Although 

many reserve personnel were mobilized for Operations 

Desert Shield and Desert Storm, those operations did not 

require repeated large-scale mobilizations and extended 

tours of duty. The Army has not seen the current level of 

extended reserve mobilization since the Korean War. As a 

result, some policymakers and defense experts question 

whether the Army is using its reserve component in an 

appropriate manner and whether the reserves as currently 

structured can sustain large and extended mobilizations. 

Partly in response to those concerns, DoD recently announced a policy that reserve units should not be mobilized and deployed more than once every six years.

The modern reserve system is intended, in effect, to provide relatively low-cost surge capacity to the Army. As 

such, many elements of it appear poorly suited to augmenting the Army’s capability to sustain extended deployments. For example, reserve units have traditionally 

received equipment handed down from the active component after it received more-modern equipment, trained 

less in peacetime than their active counterparts, and expected to be mobilized infrequently and for short durations. Those circumstances have led some critics of the 

Army’s current policies to argue that reserve units should 

not be used in extended peacetime operations but rather 

only for major combat operations. Other critics, however, 

argue that if the Army intends to employ reserve units in 

extended peacetime operations, the standard of equipment and training for those units must be raised to match 

that of active units.

Some critics believe that a part-time, citizen-soldier 

model for the reserve component is incompatible with 

the Army’s implementation of the Total Force Policy. 

Because the Army’s implementation of that policy effectively requires the service to mobilize reserve personnel 

for any significant operation, it guarantees that the Army 

cannot conduct “active-only” operations. Other critics, 

however, contend that with proper management of the 

reserve component and some limited reforms, the Army 

could avoid placing an undue burden on individual 

reservists.

Deployment Speed

After Operation Desert Storm, DoD became concerned 

with the time required to deploy large forces to distant 

theaters of operations. That concern involved the belief 

that Operation Desert Shield included a lengthy period 

of time during which Iraqi forces could have invaded 

Saudi Arabia, seizing critical airfields and ports and preventing U.S. forces from easily deploying to the theater. 

That view holds that in any future scenario, opponents 

would realize that allowing the United States to build up 

overwhelming forces would guarantee their defeat, and 

thus they would rapidly move to seize the infrastructure 

on which U.S. forces depend for deployment. To counter 

that potential strategy, DoD made numerous improvements to the deployment process in the mid-1990s, including purchasing C-17 cargo airplanes; large, medium9. Strictly speaking, those divisions could be deployed if they were 

given support units normally assigned to other forces. However, 

that would render the other forces nondeployable and produce an 

equivalent effect—the Army would not be able to deploy all of its 

forces simultaneously.
CHAPTER ONE THE ARMY’S CURRENT AND PLANNED STRUCTURE 7

speed roll-on/roll-off cargo ships; and sets of equipment 

that could be stored (prepositioned) in potential combat 

theaters and on flotillas of ships. However, in some subsequent operations, especially the deployment of Task 

Force Hawk to Kosovo, it became apparent to DoD that 

U.S. forces still frequently required many months to 

deploy combat units. Most of the focus on improving 

deployment speed is concentrated on the Army because 

transporting Army units generally requires more strategic 

lift assets than does transporting the units of any other 

service.

The Administration has laid particularly heavy stress on 

improving the speed with which the United States can 

deploy forces to distant combat theaters, emphasizing 

that goal in the 2001 Quadrennial Defense Review and 

numerous other policy and planning documents. DoD’s 

formal objective, expressed in the Joint Swiftness Goals, 

is to be able to defeat the efforts of any potential enemy 

within 10 days after the beginning of a conflict, defeat 

that enemy fully within the next 30 days, and be prepared 

to engage a second potential enemy 30 days after that. 

Since U.S. forces are not currently able to deploy significant numbers of ground units within 10 days, those goals 

have inspired numerous initiatives, such as the Navy and 

Marine Corps’ sea-basing concept, that may improve 

deployment speed.10

Many defense experts believe that improving deployment 

speed is necessary for the United States to respond effectively to numerous potential threat scenarios. They contend that both Operation Desert Storm and Operation 

Iraqi Freedom were highly anomalous and have taught 

potential U.S. opponents that they cannot passively allow 

the United States to build up overwhelming forces 

nearby. Such experts tend to believe that the extremely 

difficult task of deploying ground forces to Afghanistan 

might be more representative of future conflicts and indicates a need for more cargo airplanes, smaller and lighter 

units, and advanced deployment concepts.

Other defense experts, however, question the extent to 

which increased deployment speed matters. They note 

that the United States has effectively had great discretion 

and flexibility in choosing when to initiate military operations over the past few decades. In many scenarios, U.S. 

naval and air power, which is capable of deploying much 

faster than ground units, may be sufficient to deal with 

enemy threats during the early phases of a conflict.

Quadrennial Defense Review

The Department of Defense will conduct another QDR 

in 2005. That review, according to press accounts, will 

consider how well U.S. military forces are structured to 

meet a variety of challenges. According to those accounts, 

DoD is currently considering a planning framework that 

will employ several scenarios, grouped under a rubric of 

four classes of threats.

B Traditional threats. Those threats are envisioned as scenarios involving major combat operations (“conventional warfare”), similar to Operation Desert Storm 

and Operation Iraqi Freedom, or traditional scenarios 

involving the defense of South Korea.

B Irregular threats. Those threats are envisioned as scenarios that require the United States to suppress insurgencies or combat guerrilla tactics, similar to what was 

previously referred to as “unconventional” or “asymmetric” warfare.

B Catastrophic threats. Those threats are envisioned as 

scenarios with extreme, highly damaging attacks 

against the United States or its allies. The most frequently discussed scenarios in that category revolve 

around the use of chemical, biological, radiological, or

nuclear weapons against the U.S. civilian population.

B Disruptive threats. Those threats are envisioned as relatively improbable, but potentially dramatic, events 

that might completely alter the balance of power in 

the modern world, such as if hostile nonstate actors 

gained access to technology much more advanced 

than that available to DoD. CBO is not aware of any 

discrete scenario being used to assess that category of 

threat.

For numerous reasons, CBO did not attempt to incorporate the QDR planning framework into this study. First, 

the framework is intended to examine the entire department’s ability to respond to that set of threats, whereas 

this study focuses only on the Army. Second, DoD’s scenarios for the QDR are classified and have not been released to the public. Finally, by their nature, some of the 

threats being considered do not appear amenable to 

quantitative analysis.

10. For more details about sea basing, see Congressional Budget 

Office, The Future of the Navy’s Amphibious and Maritime Prepositioning Forces (November 2004). 
8 OPTIONS FOR RESTRUCTURING THE ARMY

Planned Changes in the

Army’s Structure

In February 2004, the Chief of Staff of the Army (CSA), 

General Peter Schoomaker, announced a plan that would 

involve an extensive restructuring effort to convert the 

Army into a set of modular combat and support brigades. 

That modularity reorganization—in addition to some 

other (more limited) planned changes—will alter the size 

and structure of the Army over the next few years.

The major elements of the modularity plan are to increase the number of combat brigades in the Army, standardize the types of combat and support brigades somewhat, convert the division to a more flexible echelon with 

variable numbers of subordinate combat and support brigades, and merge the functions currently performed by 

the corps and theater levels of command. According to 

the Army, modularity will improve the service’s combat 

power and permit it to be more flexible and rapidly deployable. (See Appendix B for a more detailed discussion 

of the modularity plan and some of the potential issues 

associated with it.)

Other initiatives that will change the Army over the next 

few years include a temporary increase in the size of the 

Army, ordered by the Secretary of Defense; a permanent 

increase in the size of the Army, authorized by the Congress; a directive to move some forms of support units 

from the reserve component to the active component, 

ordered by the Secretary of Defense; a continuing initiative—the Army National Guard Divisions’ redesign 

study—to convert some unsupported National Guard 

combat brigades into support forces, undertaken by the 

Army; and a plan to establish “individuals” accounts 

(TTHS accounts) in the Army Reserve and National 

Guard, also undertaken by the Army. In addition, the 

Army’s modernization plans call for a long-term shift toward units equipped with light armored vehicles.

Modularity

CSA Schoomaker’s modularity initiative is most noteworthy for his plan to increase the number of combat brigades in the active Army from 33 to either 43 or 48. 

However, the initiative calls for other changes as well, and 

successfully executing those changes will require making 

numerous adjustments to the Army’s EAD support units.

Under the modularity plan, combat brigades (called 

“Units of Action” in the plan) would be standardized as 

light, medium, or heavy, with two subordinate combat 

battalions and a more robust set of support units included in the brigades.11 The premodular force, by contrast, contains numerous types of combat brigades—including armored, mechanized infantry, Stryker, light 

infantry, airborne, and air assault, each with its own 

structure—with each brigade including three subordinate 

combat battalions and a more limited set of support 

units. (See Appendix A for a detailed comparison of the 

different types of brigades.) Although the active Army 

will have a larger number of combat brigades under the 

modularity plan, the number of combat battalions in the 

active Army component either will not increase much 

(from 98 to 102) or will decrease (to 92) because each 

brigade will have fewer subordinate combat battalions.12

That effect would be offset, however, by an increase in 

the number of combat companies in each battalion in the 

modular plan. Overall, once the effects of differently 

sized units have been removed, it appears that the 48-

brigade plan would increase the Army’s combat forces by 

about 5 percent, whereas the 43-brigade plan would produce almost no change in the amount of combat forces 

available to the Army.13 In both the 43- and 48-brigade

11. The new light and heavy brigades would have two subordinate 

combat battalions each. The medium Stryker brigades would 

remain in their current configuration, with three battalions. Some 

Army planning documents indicate that the Army may seek to 

add a third battalion to the light and heavy brigades at some 

point, if feasible. In addition, the Army still plans to introduce 

Future Combat Systems brigades with three subordinate combat 

brigades beginning in 2015.

12. Those numbers differ slightly from the results of multiplying the 

number of brigades by the number of battalions per brigade 

because in the Army’s current structure, one brigade (the 173rd 

Airborne) has only two battalions. In the modular force, the Army 

will retain Stryker BCTs in their current structure, with three battalions per BCT, and may retain ACRs in their current structure, 

with three squadrons (battalion-sized units) per ACR.

13. That comparison is based on maneuver units. There does not 

appear to be a strict definition of such units, but they are generally 

accepted to be front-line combat units capable of closing with the 

enemy by means of fire and maneuver. CBO assumed—on the 

basis of units’ composition and missions—that armor and infantry companies count as maneuver forces, as do armored cavalry 

troops from armored cavalry regiments. It is possible to argue that 

other types of units (such as attack helicopter units, other reconnaissance troops, and so on) should also be considered maneuver 

units. Including those units would alter the results of this comparison. In particular, including reconnaissance troops would suggest 

that the 43-brigade force would have about 19 percent more, and 

the 48-brigade force about 27 percent more, combat units than 

the current force.
CHAPTER ONE THE ARMY’S CURRENT AND PLANNED STRUCTURE 9

Table 1-1.

Number of Major Combat Units 

and Personnel in Those Units in

Premodular and Modular Forces

Source: Congressional Budget Office.

Notes: For more details about the numbers in this table, see Tables 

B-1 and B-2 in Appendix B.

Combat units include armored, mechanized infantry, light 

infantry, airborne, air assault, and Stryker brigades, battalions, and companies, as well as armored cavalry regiments, 

squadrons, and troops. (These numbers assume that the 3rd 

Armored Cavalry Regiment is retained in its current form.)

a. Personnel numbers are rounded to the nearest 5,000.

forces, however, more of the Army’s combat power would 

be concentrated in the active component than is the case 

today, with the active Army’s combat forces increasing by 

either 19 percent or 32 percent and the National Guard’s 

combat forces decreasing by 19 percent (see Table 1-1). 

Presumably, that change would also make the active 

Army even more dependent on reserve support units than 

it is currently. 

In addition to changing the number and type of combat 

brigades in the Army, the modularity plan envisions eliminating the traditional division structure. Instead, divisions (called “Units of Employment (X)” in the plan) 

would consist of a relatively small headquarters element 

that would command a set of interchangeable combat 

and support brigades. Most divisions would have a standard set of brigades, with four combat brigades, an artillery brigade (for heavy divisions), an aviation brigade, 

and a support brigade (with logistics and maintenance 

units). Although that structure would be relatively similar 

to today’s division—which has three combat brigades, an 

artillery brigade, an aviation brigade, an engineer brigade, 

a support brigade, and a variety of different battalions 

(called the division troops)—it would, in theory, be simpler to alter by changing the number and mix of brigades 

in response to different missions.

Similarly, the Army plans to merge the corps and theater 

levels of command into a single level (called a “Unit of 

Employment (Y)” in the plan) that would consist of a 

small and flexible headquarters element commanding a 

flexible set of divisions and support brigades. The support brigades would be standardized to permit more flexible tailoring of any given force to a specific theater and 

mission.14

The Army has announced the design of the new combat 

and aviation brigades that will be used in the modularity 

plan, but it has not announced the design of the majority 

of support brigades. More important, the Army has not 

announced how many support brigades of each type the 

modularity plan will require. Converting the Army’s 

combat brigades (and increasing their number to 48) will 

require 25,000—or possibly 45,000—additional active 

personnel. The Army will probably require more support 

brigades for the additional combat brigades. Therefore, 

unless the Army dramatically reduces the level of support 

units it has traditionally needed in the past, it may also 

face an increased need for EAD support personnel under 

the modularity plan. 

The Army has received permission from the Secretary of 

Defense to increase its size by 30,000 temporarily, thus 

enabling it to convert its combat brigades and grow to 43 

or perhaps 48 combat brigades. To avoid a permanent 

increase in size, however, the Army has said it will identify 30,000 personnel positions that could be eliminated 

(ideally, from TDA or TTHS positions) by 2011. HowBrigades

Current force 33 36 69

43-brigade force 43 34 77

48-brigade force 48 34 82

Battalions

Current force 98 108 206

43-brigade force 92 70 162

48-brigade force 102 70 172

Companies

Current force 297 327 624

43-brigade force 353 265 618

48-brigade force 393 265 658

Personnela

Current force 170,000 170,000 340,000

43-brigade force 195,000 150,000 345,000

48-brigade force 215,000 150,000 365,000

Total Army

Active

Component

Reserve 

Component

14. The Army also appears to have decided that it may require an 

intermediate command level between the Unit of Employment 

(X) and the Unit of Employment (Y) for larger theaters and has 

described a possible “Three-Star” Unit of Employment (X) to fill 

that role. That level would be commanded by a lieutenant general 

and presumably would fill the role of the current corps.
10 OPTIONS FOR RESTRUCTURING THE ARMY

ever, it is unclear whether the Army will be able to successfully identify sufficient positions, whether it can grow 

to 48 combat brigades without additional personnel, or 

how future decisions on the support units needed for 

modularity might affect the Army’s overall personnel requirements. If the Army requires additional personnel for 

the full 48-brigade force, cannot identify sufficient TDA 

and TTHS positions to eliminate, and requires levels of 

support in line with historical norms, the Army might 

need as many as 60,000 additional personnel overall (although not all of those personnel would necessarily need 

to be in the active component). Even under those circumstances, the Army would still lack sufficient units to fully 

support all National Guard major combat units.

Some proponents of the modularity plan have argued 

that modular brigades will be easier to deploy than premodular ones. The equipment associated with modular 

brigades weighs about as much as the equipment associated with current brigades, so it is unlikely that deploying 

modular BCTs will be any easier than deploying current 

BCTs. However, if modular brigades require fewer support units to be deployed with them, the weight of all the 

equipment in the package of combat and support units 

could be less than that used by the current force and thus 

make the modular forces easier to deploy.

Increased End Strength

To implement the modularity plan, the Secretary of 

Defense has granted the Army temporary authority to 

increase its size beyond the 482,400 active personnel it 

was allowed by law in 2004. The authority allows the 

Army to increase by 30,000 personnel through 2007.

In the 2005 defense authorization act, the Congress increased the Army’s authorized maximum and minimum 

end-strength levels to 502,400 active personnel.15 However, the authorization was enacted after the Congress 

had provided appropriations for 2005, which included 

funds for only 482,400 active-duty personnel, so any increase in personnel above that level will have to be funded 

with supplemental or reprogrammed appropriations. The 

authorization act also formally conferred power on the 

Secretary of Defense to authorize a temporary 30,000 

increase in the size of the Army, granting that authority 

through 2009. It is unclear how those Congressional 

actions will affect the Army’s modularity plan or whether 

the 20,000 permanent increase in end strength will offset 

the Army’s 30,000 temporary increase.

Active- and Reserve-Component Reallocation

In response to DoD’s policy of not mobilizing reserve 

personnel more often than one year out of every six and a 

stated goal by the Secretary of Defense of not needing to 

mobilize reservists within the first 15 days of a conflict, 

the Army has embarked on a limited program of moving 

some units from one component to the other. That initiative will shift about 10,000 positions between the active 

and reserve components.16 Some of those shifts will simply move units between components (in other words, an 

active unit will be deactivated, and the same type of unit 

will be activated in the reserves). However, some unit 

changes will be achieved by eliminating certain types of 

support units (including field artillery and short-range 

air-defense artillery units) that the Army believes it does 

not need as much as other types of support units.

Army National Guard Division Redesign Study

The Army National Guard Division Redesign Study is an 

initiative that began in the late 1990s in response to situations in which the Army does not have sufficient numbers of support units to mobilize and deploy all of the 

National Guard divisions. The initiative was originally 

intended to convert 12 combat brigades from the National Guard divisions into multifunctional support brigades, thus providing support for more of the remaining 

combat brigades in the National Guard divisions. That 

plan was intended to proceed in four phases, with each 

phase converting three combat brigades. Only Phases I 

and II ever received funding, however. Phase I is now 

largely complete, and Phase II is scheduled to take place 

in 2006. To some degree, the ongoing initiative will complement the Army’s modularity redesign, which also envisions reducing the number of combat brigades in the 

National Guard.

Reserve-Component TTHS Accounts

Traditionally, only the active Army had a TTHS account, 

but recent Army plans include establishing such individu15. End strength is the number of personnel in the Army at the end of 

the fiscal year. Although the Congress sets both a maximum and a 

minimum level, those levels have traditionally been the same 

number. The Army is allowed to vary by no more than 3 percent 

from that level of personnel (referred to as the “operating strength 

deviation”).

16. The Army has also announced that it will seek to shift up to 

100,000 additional positions over the next few years.
CHAPTER ONE THE ARMY’S CURRENT AND PLANNED STRUCTURE 11

als accounts on a small scale for both the Army Reserve 

and the Army National Guard. To free up sufficient personnel slots to establish those accounts, the Army will 

have to eliminate some reserve units. However, the units 

that remain will probably be better manned, because they 

will no longer need to maintain personnel on their unit 

rosters who are not actually available.

Stryker Brigades and Future Combat Systems

The Army is currently investing significant funds to develop and procure two types of new light armored vehicles. The first type, the family of Stryker vehicles, is intended to allow the Army to convert five active and one 

National Guard combat brigades to a medium-weight 

configuration. Two of those conversions have been completed, and one is currently under way.

The second type of light armored vehicle would be developed under a much more extensive initiative known as 

the Future Combat Systems (FCS) program. The FCS 

program is intended to develop many new technologies 

and types of equipment for the Army, including communications networks, computer technologies, unmanned 

aerial vehicles, and intelligent munitions. One of the program’s central elements is a proposed new family of light 

armored vehicles. The Army ultimately intends to replace 

all, or nearly all, of its combat brigades with FCSequipped medium brigades, eventually eliminating heavy 

and light forces (with the possible exception of airborne 

forces).

The FCS program not only would alter the types of brigades in the Army but also could alter their size. Although the Army does not currently envision fielding an 

entire FCS-equipped combat brigade until the end of calendar year 2015, the Army’s Training and Doctrine Command has developed preliminary unit designs showing 

that FCS brigades could have about 2,200 personnel, and 

FCS divisions could have about 10,000 personnel. Because those units would be about two-thirds of the size of 

existing units and would, if the Army’s plans for the FCS 

are fully realized, require much less of certain types of 

support (such as maintenance), the FCS program might 

lead to a significant reduction in the Army’s personnel 

requirements.

Although they are not the only justification for mediumweight units, the Army’s arguments for the Stryker and 

FCS have laid great emphasis on their potential to reduce 

the time it takes Army forces to deploy. That reduction 

could come in two ways. First, the lightly armored vehicles in such units simply weigh less than the heavily armored vehicles the Army currently fields. Second, because heavy units require more support units than light 

units do, medium units should require fewer support 

units than heavy units do and require correspondingly 

less lift.

CBO found that although the difference in unit equipment weight among light, medium, and heavy forces is 

large, the difference in the time needed to deploy fully 

supported light, medium, and heavy forces is not very 

large. Heavy brigades using equipment prepositioned on 

ships require about twice as much time to deploy as light 

units do. For larger formations, however, a full package of 

heavy units generally requires only about 10 percent to 

25 percent more time to deploy than does a full package 

of light units.

For air deployment, the weight of unit equipment is the 

primary factor affecting deployment speed. The equipment associated with a light BCT weighs about 4,000 

tons; with a Stryker BCT, about 13,000 tons; and with 

a heavy BCT, about 25,000 tons.17 Similarly, the equipment associated with a light division weighs about 

20,000 tons, whereas the equipment associated with a 

heavy division weighs about 100,000 tons. (Currently, 

there are no medium divisions, but CBO estimates that a 

medium division would have about 60,000 tons of equipment.) However, when those units are deployed with 

their associated support units (as they almost always are), 

the difference in the weight of all the unit equipment that 

must be shipped with each BCT—light, medium, or 

heavy—becomes much less significant because many 

types of support units are common to all types of forces 

and do not vary. In fact, the weight of the total force 

package (with combat and support units) is about 80,000 

tons for a light division and 180,000 tons for a heavy 

division. (CBO estimates that a medium division would 

have about 120,000 tons of equipment with its support 

package.) The relatively large differences in weight 

among types of BCTs do not produce similarly large differences in weight among force packages. Thus, equipping combat units with lighter equipment does not 

reduce deployment timelines by a great deal.

17. The term ton in this study refers to a short ton, which weighs 

2,000 pounds.
12 OPTIONS FOR RESTRUCTURING THE ARMY

The United States does not generally deploy combat 

units by air, because any sizable, fully supported unit 

tends to have so much equipment that deployment by sea 

is faster. Since a C-17 cargo plane will generally transport 

about 45 tons per sortie, deploying large units can easily 

require thousands of sorties. For sea deployment, the primary factor affecting speed is the square footage needed 

to stow unit equipment. The differences in that square 

footage for light and heavy units are somewhat smaller 

than the differences in how many tons of equipment 

those units have. A light division requires about 600,000 

square feet to stow its equipment, whereas a heavy division requires about 1.4 million square feet.18 As with 

tons, those figures are larger when the full set of support 

units is included, and the difference between light and 

heavy units becomes less pronounced. In addition, because the U.S. fleet of sealift ships can transport very large 

amounts of cargo (the primary types of cargo ship can 

transport about 380,000 square feet of equipment each), 

deploying a single light or single heavy division by sea 

does not require appreciably different amounts of time—

the U.S. fleet of cargo ships is capable of transporting 

either type of unit without multiple trips.

18. When units are measured in square footage, heavy divisions 

require a bit more than twice as much lift capacity as light divisions, compared with five times as much when measured in tons. 

That difference results because unit equipment in heavy divisions 

is, on average, considerably denser than that in light units.
2

Alternatives for the Army’s Force Structure

As discussed in the previous chapter, critics have 

raised concerns about the Army’s current size and structure, its ability to fight wars and sustain extended deployments, its dependence on reserve units, and the speed 

with which it can deploy. This chapter examines ways to 

address those concerns by altering the Army’s size and 

structure. The Congressional Budget Office analyzed 

eight alternatives, evaluating the costs, advantages, and 

disadvantages of each.

Policy Choices and Their Implications

Any proposed alternative force structure for the Army 

will require trade-offs, either because it will incur additional costs or because it will reduce the Army’s ability to 

perform some mission. To demonstrate the effects of 

changing the Army’s force structure, CBO examined the 

implications of varying three attributes of the current 

force structure:

B The overall size of the Army, as measured in major 

formations (theaters, corps, divisions, and brigades);

B The distribution of combat and support forces between the active and reserve components of the Army; 

and

B The types of major combat forces and the levels of 

support forces associated with them.

Increasing the Size of the Army

Increasing the overall size of the Army is the most direct 

way to address concerns about its ability to fight more 

than one conflict simultaneously or its ability to sustain 

large forces on extended deployments. By adding combat 

forces to the Army, along with the echelons-abovedivision support forces that those combat forces would 

need, the Army would gain more combat units that could 

be used for warfighting or peacekeeping missions. Alternatively, if the Army must sustain any given level of commitment for extended deployments, having a larger Army 

would provide a larger pool of forces that would be available to meet that commitment, reducing the frequency 

with which any given unit would need to be deployed 

(thus reducing stress on personnel and units).

The primary disadvantage associated with increasing the 

size of the Army is cost. Adding active divisions to the 

Army requires about 40,000 personnel per division 

(about 15,000 for the division; 15,000 for EAD support 

units; and 10,000 for Table of Distribution and Allowances positions and trainees, transients, holdees, and students positions). Additional personnel generate significant recurring costs, some of which (such as health care 

and pensions) generate long-term obligations for the government. Furthermore, adding units to the Army would 

incur one-time costs to purchase equipment for the new 

units. In this study, CBO also assumes that the Army 

would modernize any new forces over time, so its procurement budget would increase to allow the Army to 

purchase newer, more advanced equipment as time

went on.

It is also possible to create more combat forces by reducing the amount of support forces in the Army. To illustrate the potential for different policy choices, several of 

CBO’s alternatives create additional combat forces by 

either reducing the levels of some types of EAD support 

units or by eliminating some echelons (such as the corps). 

In those alternatives, the costs for increasing the number 

of combat forces would be reduced, but the resulting 

force would be somewhat less capable of some types of 

warfighting.

Reducing Dependence on the Reserve Component

Although the Army’s current structure makes active combat units very dependent on reserve EAD support units, 

that dependence could be reduced by increasing the 

CHAPTER
14 OPTIONS FOR RESTRUCTURING THE ARMY

number of units in the active component, according to 

critics of the Army’s need for extensive reserve mobilization. The Army could achieve that result through two 

distinct approaches. First, the Army could simply create 

additional EAD support units in the active force, reducing the need to mobilize reserve EAD support units. Second, the Army could swap units between components, 

using the personnel freed up in one component to create 

a unit equivalent to the one disbanded in the other component. Although the latter method would not reduce 

the overall dependence on reserve units, it could reduce 

the Army’s need for reserve mobilization in peacekeeping 

operations by concentrating units necessary for such operations (such as military police) in the active component, while concentrating units that are not needed for 

such operations (such as artillery) in the reserve component.

The primary disadvantage of reducing dependence on the 

reserves is the cost associated with creating additional 

EAD support units in the active force. Such costs are similar to those associated with increasing the size of the 

Army. However, CBO assumed that if the number of active EAD support forces were increased, the number of 

reserve EAD support forces could be decreased by an 

equivalent amount, offsetting the costs of adding active 

EAD units somewhat. (Active units, however, cost more 

than equivalent reserve units.)

Creating New Types of Units

Numerous proposals to reform the Army to better address current concerns involve creating new types of 

units. The Army frequently reorganizes its forces and is 

now engaged in one such restructuring. CBO generated 

alternatives that would respond to four major proposals 

that have been made in public debate:

B “Peacekeeping” formations. Many observers have suggested that the Army’s practice of using combat forces 

for peacekeeping operations may be inappropriate. A 

number of defense experts have suggested creating formations oriented around military police, civil affairs, 

engineers, and other types of units that have been in 

high demand for peacekeeping operations.

B “Brigade-based” formations. Many critics have argued 

that the Army’s command echelons, which are large 

and inflexible, date back to World War II. Some defense experts have argued that by constructing relatively independent brigades and eliminating one or 

more of the higher echelons (division, corps, or theater), the Army might be able to wage war more rapidly and effectively.

B “Expeditionary” formations. Many defense analysts argue that the ability to rapidly deploy requires changes 

in organization, not just equipment. Some defense experts argue that the Marine Corps’ structure of Marine 

expeditionary forces offers an example of “best practices” for organizing land forces to be able to rapidly 

deploy to distant conflicts and that the Army could be 

restructured in a manner more similar to the Marine 

Corps.

B “Transformational” formations. In recent years, a large 

section of the defense community has argued that advances in precision-guided munitions, sensors, and 

communications networks have made it possible for 

relatively small, high-technology forces to defeat much 

larger conventional opponents. Many defense experts 

within that community have argued that smaller, 

lighter ground forces equipped with long-range precision firepower would have superior abilities to fight 

wars compared with traditional Army forces.

Each type of formation has various advantages and disadvantages, many of which are connected with how the 

force that uses the new formations is designed. For example, the number of additional personnel the Army can 

sustain in extended deployments using peacekeeping formations depends in part on the design of the peacekeeping units but also on how many of them the Army might 

establish.

Measures for Evaluating the Effects of 

Changing the Army’s Force Structure

To show the specific advantages and disadvantages of 

changing the Army’s force structure, CBO designed and 

analyzed eight alternative force structures. They are divided into three groups that focus on each major type of 

change—increasing the size of the Army, reducing dependence on the reserve component, or creating new 

types of units. The alternatives include a wide array of 

policy choices, ranging from those that would represent 

relatively limited changes to the current force to those 

that would represent relatively dramatic changes to the 

current force.
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 15

Table 2-1.

Size and Composition of the

Premodular Army

Source: Congressional Budget Office.

None of the alternatives, however, reflect the Army’s current modularity plan. As discussed in the previous chapter, CBO does not have sufficiently detailed descriptions 

of those plans, including their budgetary implications, to 

fully analyze the Army’s proposed changes. In particular, 

the Army has not yet decided exactly how many major 

combat units it will have, nor has the Army released any 

details about the support forces that will be needed for a 

modular Army. In an effort to combine CBO’s limited 

understanding of the modularity plan with this analysis, 

CBO briefly assessed how modularity might affect each 

alternative. For example, although CBO is not sure exactly what support forces will be needed for modular divisions, the alternative presented here to add divisions to 

the Army would require similar trade-offs in a modular 

Army (gaining more capability to wage wars and sustain 

extended deployments by increasing the size of the Army 

and incurring additional costs).

CBO used several measures to compare the alternatives 

with one another and with the Army’s current force 

structure. The first set of measures describes the overall 

size and composition of the force (see Table 2-1). It 

includes:

B The number of active- and reserve-component personnel required for the force;

B The total number of corps, divisions, and brigades in 

the force; and

B The number of fully supported combat brigades the 

Army could deploy overseas to a military contingency.

The second set of measures describes the estimated cost 

of the force (see Table 2-2). It includes:

B The five-year (2006-2010), 10-year (2006-2015), and 

entire long-term projection-period (2006-2022) costs 

for procuring equipment for the force and for continuing to modernize that equipment over time; and

B The five-year, 10-year, long-term, and recurring costs 

for military personnel and for the force’s operations 

and maintenance.

The third set of measures describes the force’s ability to 

fight wars (see Table 2-3). It includes:

B The number of combat brigades and personnel the 

Army would use for a notional major combat operation;

B The number of support personnel who could be provided for combat personnel in a major combat operation;

B The number of reserve personnel who would be mobilized for a major combat operation;

B The number of major combat operations the force 

could simultaneously conduct; and

B The speed with which the force could deploy a single 

brigade, division, corps, or theater overseas.

Table 2-2.

Cost of the Premodular Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

482,400 555,000 1,037,400

31 4

10 8 18

33 36 69

Supported

brigades 33 22 55

Active Reserve

Component Component

Total Brigades

Total Army

Personnel

Corps

Divisions

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

2010 2015 2022 2022

Costs in

Annual

Total Costs Recurring

2006- 2006- 2006-
16 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-3.

The Premodular Army’s Ability to

Fight Wars

Source: Congressional Budget Office.

The fourth set of measures describes the force’s ability to 

sustain extended deployments (see Table 2-4). It includes:

B The number of personnel and brigades that could be 

sustained in extended deployments while using only 

active combat forces and the number of reserve personnel who would be mobilized to support those 

deployments; and

B The number of personnel and brigades that could be 

sustained in extended deployments while using active 

and National Guard combat forces and the number of 

reserve personnel who would be mobilized to support 

those deployments.

In analyzing the Army’s premodularity force structure, 

CBO used a notional force for a major combat operation. 

That notional force, composed of one theater, two corps, 

six divisions, and 20 combat brigades, is not identical to 

the specific forces used in any operational plans or recent 

military operations, although it approximates the size and 

composition of forces assumed in war games as necessary 

to prevail in a major conflict. By comparison, Operation 

Desert Storm was conducted with 23 Army brigades, 

whereas Operation Iraqi Freedom was conducted with 

about eight Army brigades. (Both operations included 

Marine Corps and allied forces as well.)

In two alternatives, CBO adjusted the size of the notional 

force to reflect the potential qualitative improvements in 

warfighting that those alternatives might have. Proponents of both the brigade-based Army and the transformational Army claim that a smaller force structured in 

the manner they describe would be as effective as a much 

larger force without those structures. Although CBO was 

unable to assess the validity of such qualitative claims, it 

evaluated a notional force that was only 60 percent of the 

size of the notional force used in other alternatives to illustrate the potential benefits that such claimed improvements could offer. In those cases, it is possible for a force 

to be less capable of fighting wars overall (in the sense of 

having fewer combat brigades), but more capable of 

fighting multiple wars simultaneously (in the sense that 

the number of brigades required for a major combat 

operation would be smaller).

Similarly, for deployment times, CBO estimated an average time to deploy a given force. That average includes 

several different scenarios, with forces originating from 

different points (the East and West coasts of the United 

States) and being deployed to different points (in Africa, 

Asia, and the Middle East). As with the notional major 

combat operation force, that deployment time approximates the time to deploy a force but is not identical to 

specific timelines used in operational plans or recent military operations. Ground forces used for Operation Desert 

Storm required about five-and-a-half months to deploy,

Table 2-4.

The Premodular Army’s Ability to

Sustain Extended Deployments

Source: Congressional Budget Office.

Personnel 285,000

 Brigades 20

1.76

109,000

Active Army only 1.65

Total Army 2.75

First brigade 14

First division 20

First corps 53

First theater 102

Deployment Time (Days)

Reserve-Component Personnel

Number of Major Combat Operations Possible

Current

Force

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel

Mobilized and Deployed

 89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

Active Army

Only Total Army

Brigades

Personnel Mobilized

Maximum Sustained

Reserve-Component

Deployment

Personnel
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 17

Table 2-5.

Sizes of Past U.S. Peacekeeping and 

Occupation Forces

Source: Congressional Budget Office based on information from 

the RAND Corporation.

Note: The information in this table is an updated version of Table 

S.1 from James Dobbins and others, America’s Role in 

Nation-Building: From Germany to Iraq, MR-1753-RC (Santa 

Monica, Calif.: RAND, 2003). The data represent peak sizes 

of the U.S. forces involved in the operations, but such forces 

tended to vary substantially over time.

whereas ground forces used for Operation Iraqi Freedom 

required about three-and-a-half months to deploy (not 

including the continuing flow of units that were deployed 

during combat operations in Operation Iraqi Freedom—

the 4th Infantry Division, 3rd Armored Cavalry Regiment, and 1st Armored Division).

Finally, CBO’s estimates of the size of the force the Army 

could sustain for extended deployments is a maximum 

size force the Army could sustain absent any other commitments. The Army, however, currently has a number 

of such commitments, including those in South Korea, 

Kosovo, the Sinai Peninsula, and Afghanistan. Maintaining those commitments would reduce the Army’s ability 

to sustain large numbers of forces for extended deployments. The United States historically has been involved 

in numerous extended deployments, but those deployments have varied greatly in size and duration (see 

Table 2-5 for historical peak sizes of U.S. peacekeeping 

and occupation forces).

Additional Considerations

In order for CBO’s analysis to fully reflect the changes 

that any given alternative would have on the entire 

Army’s force structure, CBO made some additional 

technical assumptions about how changes in each alternative would affect each measure of performance. (See 

Appendix C for additional detail about the measures 

CBO used in this analysis.)

Increasing the Size of the Army. For alternatives that increased the size of the Army, CBO created only fully supported combat formations. In those alternatives, the size 

of the increase in personnel the Army required included 

three components: personnel to man the additional combat forces, personnel to man the EAD support units for 

those additional combat forces, and additional personnel 

to account for increased overhead for a larger force. Because of the inclusion of those components, the number 

of additional personnel required to increase the size of the 

Army is always larger than the nominal size of the combat 

units added. 

The increase in overhead personnel is necessary because 

the number of TDA and TTHS personnel the Army 

requires has historically varied with the total size of the 

Army.1

 That relationship results because a larger Army, 

with more units and equipment, simply requires more 

personnel managers, more equipment managers, more 

trainers, and so forth. Similarly, a larger Army must 

recruit more personnel, leading to more soldiers in basic 

or advanced training; has more soldiers with temporary 

medical disabilities; and has more soldiers moving between assignments. In each option where CBO varied the 

overall size of the Army, it included a factor to allow for 

the additional (or reduced) number of personnel required 

for TDA units and for TTHS personnel. It is possible 

that the ratio of the Army’s overhead personnel to deployable units could change in the future, but CBO had 

no basis to assume that the Army would achieve any 

greater level of efficiency in any of the alternatives examined in this paper.

Reducing Dependence on the Reserve Component. For 

alternatives that altered the active Army’s dependence on 

reserve support units, CBO’s measures of how many reserve personnel would need to be mobilized or deployed 

depended on a number of factors. There were three conceptually separate categories that could require reserve 

personnel to be mobilized:

B Mobilized and deployed overseas;

Location

West Germany 1,600,000 1945–1952

Japan 350,000 1945–1952

Somalia 28,000 1992–1994

Haiti 21,000 1994–1996

Bosnia 20,000 1995–2004

Kosovo 15,000 1999–present

Afghanistan 18,000 2001–present

Iraq 180,000 2003–present

Peak Size of Force Duration

1. See John R. Brinkerhoff, The Institutional Army, FY1975–

FY2002, Document No. D-2695 (Alexandria, Va.: Institute for 

Defense Analyses, April 2002).
18 OPTIONS FOR RESTRUCTURING THE ARMY

B Mobilized and in training, preparing to deploy overseas; and

B Mobilized to fill in for deployed active-component 

units at U.S. bases.

The first category of reserve personnel is relatively easy to 

estimate, since it is simply the number of reserve personnel in units required to support active units, in addition 

to any National Guard combat forces and reserve support 

units that may be employed.

The second category of reserve personnel is primarily relevant for peacekeeping operations, which may last for 

many years. In such operations, if reserve units are deployed, at some point a new set of reserve units must be 

mobilized and trained to full proficiency to replace the 

deployed units.2

 To smoothly transition from the deployed unit to its replacement unit, the latter must be 

mobilized some months before the transition to allow 

time for training and deployment. Thus, the number of 

reserve personnel mobilized for such an operation will 

frequently be greater than the number of reserve personnel deployed (as has been the case with operations in Iraq 

and Afghanistan). That would not generally be the case 

for a purely warfighting operation, however, where a 

deployment would not need to be sustained over long 

periods.

The third category of reserve personnel is associated with 

the Army’s practice of mobilizing some reservists to fill in 

for deployed active units at their home bases. That practice, known as “backfill,” allows bases to continue functioning in a normal manner when their units are deployed (for example, reserve personnel might be called 

up to provide guards for the installation). Although the 

number of reservists mobilized for that purpose is smaller 

than the number of active-component personnel for 

whom they backfill, reserve-component mobilization can 

be significant if the active force is heavily committed. 

Thus, even if the Army was able to conduct an operation 

by deploying only active units, it would probably still 

mobilize reserve personnel (although it would not deploy 

those personnel overseas).

The level of reserve mobilization that CBO analyzed in 

this study does not necessarily correspond to the number 

of individual reservists who would be mobilized. Instead, 

it represents the average number of reservists who would 

be mobilized in an entire year (and thus is analogous to 

man-years). In certain cases, more individual reservists 

might be mobilized than the average level of reserve mobilization—for example, if reserve units were deployed 

for six months to a peacekeeping deployment and continually replaced, two individuals would be mobilized for 

each man-year of mobilization.

Creating New Types of Units. When CBO created new 

types of units, it estimated the size of the support forces 

those new units would require and the weight of the 

equipment those units would include.

In general, CBO created new units by building up new 

combinations of existing units. For example, the peacekeeping divisions CBO analyzed are a new type of division, but they are composed entirely of existing types of 

battalions. Therefore, CBO could estimate the support 

requirements and equipment weight of those units using 

existing Army units as a guide.

An additional type of change that CBO made in one alternative (to create expeditionary units) was to increase 

sealift assets and prepositioned equipment sets on ships 

that the Army could use. Additional sealift assets improve 

the time it takes to deploy Army forces by simply providing more capacity to ship forces overseas. Prepositioned 

equipment—sets of Army equipment loaded onto large 

cargo ships permanently stationed near potential conflict 

zones—speeds Army deployment because the equipment 

in those sets is already loaded on ships that are generally 

stationed closer to potential conflicts than ships coming 

from U.S. ports.

CBO did not increase the amount of airlift assets in any 

alternative because the United States generally does not 

transport unit equipment by air; airlift can only lift a very 

2. The Army generally assumes that a reserve unit will require about 

a month for mobilization activities (such as medical checks). Some 

types of units (transportation units and other such support units, 

for example) generally do not require extensive post-mobilization 

training and can be deployed relatively rapidly. Other units, especially combat units, generally require extensive post-mobilization 

training (such as a rotation to the National Training Center) and 

may need up to an additional six months before they can be 

deployed. Reserve units also generally remain mobilized for a 

period of time after returning from a deployment, allowing reserve 

personnel to take leave accumulated while deployed and engage in 

some post-deployment activities.
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 19

limited fraction of what sealift can; and in many potential 

scenarios, the infrastructure available for airlift is poor 

enough that the existing fleet of cargo aircraft could not 

be fully employed.

Costs. All of CBO’s costs were estimated using the forces 

in DoD’s Future Years Defense Program for fiscal years 

2005-2009 as a base. Costs for alternatives represent the 

incremental change in funding required compared with 

that base. Operation and support (O&S) costs were estimated using various sources of budgetary data and included, among other things, the costs associated with pay 

and benefits for personnel, spare parts, and fuel. All costs 

are in billions of 2006 dollars.3

CBO separately estimated investment costs, which represent the costs to develop and acquire new weapon systems 

and equipment; operation and support costs, which represent the costs for pay and day-to-day operations; and 

construction costs, which represent the costs to build and 

maintain military facilities. Investment costs beyond 

2009 were estimated against CBO’s long-term projection 

of defense plans.4

 (See Appendix D for additional details 

about how CBO developed costs for the alternatives.)

Alternatives That Would Increase the 

Size of the Army

CBO’s first two alternatives illustrate the costs and effects 

associated with increasing the size of the Army. Many 

observers have suggested that a larger Army is needed to 

improve the Army’s ability to deal with stressful missions 

such as the occupation of Iraq, respond to other threats 

that could arise during the occupation of Iraq, or reduce 

the stress on the reserve component. In the past year, the 

Secretary of Defense has authorized a temporary increase 

in the size of the Army (by 30,000 personnel), the Congress has authorized an increase of 20,000 active personnel, and many external observers have called for a larger 

Army.

Alternatives 1A and 1B would both increase the size of 

the Army by two divisions but do so in different ways. 

Alternative 1A would increase the overall size of the active 

Army, offering greater warfighting and peacekeeping capabilities at greater costs. Alternative 1B would increase 

the size of the active Army’s combat forces by reducing 

some types of support units, offering greater warfighting 

and peacekeeping capabilities, but potentially increasing 

the risk associated with some types of missions.

CBO’s alternatives specifically examined the effects of 

adding two divisions to the Army, but adding a single 

division or more than two divisions would involve similar 

considerations. CBO chose to consider the addition of 

two divisions because it is a relatively popular suggestion 

in public discussion.

Some observers have questioned whether the Army 

would be able to recruit sufficient personnel for additional forces. CBO did not analyze the potential likelihood that the Army might be incapable of recruiting additional personnel. In the 1980s, the Army was about 60 

percent larger than it currently is, the national youth cohort was slightly smaller than it currently is, and the 

Army was able to recruit all of the personnel it required 

on a voluntary basis. However, in the 1980s, the United 

States was not engaged in large, ongoing military operations, and the prospect of being deployed to such operations might deter some fraction of potential enlistees 

from joining the Army.

Alternative 1A—Add Two Active Divisions

This alternative would increase the size of combat forces 

in the Army by adding two divisions with a total of six 

combat brigades to the active component. One of those 

new divisions would be a heavy division (with three heavy 

brigades), and the other would be a light division (with 

three light brigades). Overall, this option would add 

about 78,000 personnel to the Army—57,000 active and 

21,000 reserve (see Table 2-6).

Those two divisions would require a total of about 

29,000 additional active personnel. This option also 

would add the full range of support units associated with 

3. Although discounting costs over time to generate the net present 

value of policy choices is a common analytic practice, CBO chose 

not to develop net-present-value calculations for this study. 

Although such calculations are generally appropriate for any 

stream of costs that vary over time, their use is rare in the context 

of national defense and would be difficult to compare with standard sources of information about DoD’s budget.

4. Congressional Budget Office, The Long-Term Implications of Current Defense Plans: Summary Update for Fiscal Year 2005 (September 2004). 
20 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-6.

Effects of Alternative 1A on the Size 

and Composition of the Army

Source: Congressional Budget Office.

two divisions (including corps support groups, corps artillery brigades, and so forth). Those support units would 

preserve the Army’s current mix of active- and reservecomponent support units and would require about 

12,000 additional active and 18,000 additional reserve 

personnel. This option also would increase the number of 

personnel assigned to the Army’s administrative units and 

the size of its individuals account by about 15,000 active 

and 3,000 reserve personnel to allow for increases in 

administrative workload and in the number of trainees, 

transients, holdees, and students.

Costs. Relative to the cost of maintaining the current 

force, CBO estimates the cost to implement this option 

would require an additional $31 billion to provide the 

new divisions with current equipment and to continue 

modernizing them over the 2006-2022 projection period. 

It would also require just over $95 billion in O&S and 

construction costs through 2022 and just under $7 billion annually thereafter (see Table 2-7).

The primary benefit of this alternative would be to increase the Army’s ability to fight wars and to sustain extended deployments. Its primary disadvantage would be 

the costs associated with a larger force.

Effects. With additional divisions and combat brigades, 

the Army would be more capable of fighting multiple 

wars simultaneously (see Table 2-8). Adding divisions 

also would allow the Army to send more forces to any 

given conflict, thus increasing its chances of prosecuting 

conflicts successfully or succeeding more rapidly with 

fewer casualties. 

The Army also would be more capable of sustaining 

extended deployments for peacekeeping missions (see 

Table 2-9). With more forces, the Army would be capable 

of sustaining a larger force deployed to any single commitment or maintaining a larger number of commitments overall. The additional forces available in this option would be roughly sufficient to assume one additional 

commitment of about the size of the U.S. commitment 

to Afghanistan. Alternatively, if the Army had a larger 

pool of units to draw upon for the same level of commitments, it would be able to rotate individual units and personnel through deployments at a lower pace, reducing 

stress on personnel and equipment. It would also be less

Table 2-7.

Effects of Alternative 1A on the Cost 

of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

482,400 555,000 1,037,400

3 14

10 8 18

33 36 69

Supported 

brigades 33 22 55

+57,000 +21,000 +78,000

No change No change No change

+2 No change +2

+6 No change +6

Supported 

brigades +6 No change +6

Corps

Divisions

Total Brigades

Total Brigades

Effects of Adding Two Active Divisions

Personnel

Premodular Army

Personnel

Corps

Divisions

Active Reserve

Component Component Total Army

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment +17 +19 +31 n.a.

Operation

and Support +21 +50 +95 +7 ___ ___ ____ __

Total +37 +69 +127 +7

Effects of Adding Two Active Divisions

Premodular Army

2006- 2006- 2006- Costs in

2010 2015 2022 2022

Annual

Total Costs Recurring
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 21

Table 2-8.

Effects of Alternative 1A on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

likely to have to mobilize National Guard combat units 

for peacekeeping missions, thus reducing the level of 

reserve mobilization that would be needed.

Increasing the size of the Army would not directly reduce 

the level of reserve mobilization the Army would need to 

fight wars or sustain extended deployments, since this alternative preserves the current level of active-component 

dependence on reserve EAD support units. An active 

combat force deployed to a theater of operations for conflict would still require mobilizing about the same number of reserve support units, and an extended deployment 

of any given size would still require about the same proportion of reserve units. Because this alternative would 

permit the Army to sustain larger forces deployed overseas for extended periods and would increase the size of 

the reserve component, more reserve personnel would 

need to be mobilized on average to maintain the maximum level of sustained deployment. (Sustaining the maximum deployment would also require additional reserve 

personnel to backfill for active units.) Conversely, the 

Army would be more likely to be able to meet any given 

level of commitment with active forces only, thus reducing the need for reserve-component mobilization.

Adding divisions to the Army, structured in the same 

manner as current forces, would not affect their ability to 

deploy.

Implications for the Modular Army. Although this alternative was measured against the premodular force structure, it would produce many of the same changes when 

applied to the modular Army. Adding two modular divisions would increase the Army’s ability to fight wars (by 

providing additional combat forces) or sustain extended 

deployments (by increasing the pool of available units 

and personnel). Adding two modular divisions would 

also require additional personnel and increase costs for 

investment, O&S, and construction. Since the Army’s 

modular divisions will be larger than premodularity divisions and include four brigades (versus three), adding two 

modular divisions would probably produce a larger benefit to warfighting and peacekeeping abilities but cost 

more in terms of required personnel and funding.

Alternative 1B—Add Two Active Divisions

by Reducing Support Forces

This alternative would add two active-component divisions to the Army (as in the previous option) but would 

do so without appreciably increasing the overall size of 

the Army. Instead, it would make room for additional 

Personnel 285,000 No change

Brigades 20 No change

1.76 No change

109,000 No change

Active Army only 1.65 +0.3

Total Army 2.75 +0.3

First brigade 14 No change

First division 20 No change

First corps 53 No change

First theater 102 No change

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel

Current Effects of Adding

Force Two Active Divisions
22 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-9.

Effects of Alternative 1A on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

combat units by eliminating some support units from

the Army’s current structure. Overall, this option would 

add about 6,000 active personnel to the Army (see 

Table 2-10).

This alternative would create the two additional active 

divisions by eliminating all short-range air-defense

(SHORAD) units and some corps-level field artillery 

units from the Army’s force structure while restructuring 

the remaining field artillery units. One of those new divisions would be a heavy division (with three heavy brigades), and the other would be a light division (with three 

light brigades). Specifically, this option:

B Eliminates all divisional, corps-, and theater-level

SHORAD batteries and battalions;

B Eliminates all corps-level self-propelled howitzer artillery battalions and brigades;

B Eliminates the support units associated with the eliminated SHORAD and field artillery units;

B Restructures divisional self-propelled howitzer field

artillery battalions into eight-gun batteries;

B Restructures divisional and corps-level rocketlauncher artillery battalions into nine-launcher

batteries;

B Reduces the level of logistics units associated with

supplying field artillery units; and

B Adds one light and one heavy division, along with 

EAD support units.

CBO chose to eliminate those support units because, 

according to some observers, they may not be needed and 

because the Army has taken some steps along those lines 

as part of its current reorganization. The reorganization 

of field artillery batteries into larger-sized batteries would 

change the Army from its current six-gun/six-launcher 

pattern of organization, which was adopted in 1995. 

Reverting to the prior pattern for artillery would eliminate a large number of headquarters batteries, battalions, 

and brigades (by having fewer, larger units). The justification for eliminating corps-level artillery brigades would 

be that precision munitions have vastly improved artillery

Table 2-10.

Effects of Alternative 1B on the Size 

and Composition of the Army

Source: Congressional Budget Office.

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

+12,000–15,000 +12,000–14,000

+1.5–1.9 +1.5–1.9

+5,000 +4,000–5,000

Active Army

Personnel Mobilized

Personnel Mobilized

Brigades

Deployment

Personnel

Brigades

Reserve-Component

Reserve-Component

Maximum Sustained

Effects of Adding Two Active Divisions

Only Total Army

Deployment

Personnel

Maximum Sustained

Premodular Army

482,400 555,000 1,037,400

3 14

10 8 18

33 36 69

 Supported

brigades 33 22 55

+6,000 No change +6,000

No change No change No change

+2 No change +2

+6 No change +6

Supported 

brigades +6 No change +6

Divisions

Total Brigades

by Reducing Support Forces

Personnel

Personnel

Corps

Divisions

Corps

Total Brigades

Effects of Adding Two Active Divisions

Active Reserve

Component Component Total Army

Premodular Army
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 23

Table 2-11.

Effects of Alternative 1B on the Cost 

of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

capability to the extent that fewer cannons are needed to 

produce the same effect.5 Reducing the level of logistics 

units associated with supplying field artillery units would 

be in line with a historical trend toward lower rates of 

artillery fire.6

CBO estimates that eliminating SHORAD units would 

free up about 14,000 personnel positions, and eliminating the field artillery units would free up about 16,000 

personnel positions. Reductions in support forces would 

free up another 20,000 personnel positions, yielding 

50,000 personnel positions that could be used to create 

additional combat forces and their support units. In this 

option, creating two new divisions would require about 

54,000 personnel slots, slightly more than the number of 

personnel slots freed up.7

 Allowing for increased numbers 

of overhead positions, creating two new divisions in that 

manner would require 6,000 more active personnel.

Costs. Implementing this option would cost an additional $34 billion to provide the new divisions with today’s equipment and to continue modernizing them over 

the 2006-2022 period.8 It would increase the Army’s 

O&S costs by $20 billion over that same period and by 

just over $1 billion annually thereafter (see Table 2-11).

Effects. The primary benefit of this alternative would be 

to increase the Army’s ability to fight wars and to sustain 

extended deployments, in a manner similar to Alternative 

1A (see Tables 2-12 and 2-13). Its primary disadvantage 

would be the potential risks the Army would face in conducting operations with a significant aerial threat to 

Army forces or operations that required high volumes of 

cannon artillery fire.

The benefits in this option are virtually identical to those 

in Alternative 1A. The slight reduction in personnel 

available to sustain extended deployments (compared 

with the change produced by Alternative 1A) and the reduction in personnel associated with conducting a major 

combat operation both result from this option’s somewhat smaller divisions and EAD support units. As such, 

under this option, the 20-brigade notional major combat 

operation force would require fewer personnel. Similarly, 

the size of the pool of units and personnel available for 

sustaining extended deployments is somewhat smaller.9

5. The use of precision munitions, such as the Excalibur cannon 

round, or the Guided Multiple Launch Rocket System round that 

the Army is currently introducing, should greatly reduce the number of rounds the Army will need to fire to destroy any target on 

the battlefield. Experience with such munitions in other contexts 

(such as the Air Force’s Joint Direct Attack Munition guided 

bomb kit) indicates that that effect reduces the need for launch or 

firing platforms, since each such platform can effectively “service” 

a larger number of targets.

6. Many of those points about field artillery are made in more detail 

in Office of the Secretary of Defense, Achieving a Transformation 

in Fire Support: Report to the Congress on Indirect-Fire Systems

(June 2002).

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment +16 +19 +34 n.a.

Operation 

and Support +7 +12 +20 +1 ___ ___ ___ __

Total +23 +31 +54 +1

by Reducing Support Forces

Effects of Adding Two Active Divisions

Premodular Army

2010 2015 2022

Annual

Total Costs Recurring

2022

2006- 2006- 2006- Costs in

7. In this alternative, two divisions and their EAD support units 

require 54,000 personnel, compared with the 59,000 personnel 

required in the previous option. Each division and its associated 

EAD support units require fewer personnel than in Alternative 1A 

because the new divisions, like all other divisions in this option, 

would not have SHORAD units but would have the restructured 

field artillery. 

8. Investment costs are higher for this option because CBO increased 

purchases of precision munitions to compensate for the reduction 

in artillery units.

9. The size of that reduction is, however, limited by the fact that 

CBO did not consider EAD air defense or field artillery units useful for peacekeeping. Thus, eliminating some of those units would 

not reduce the pool of units the Army could draw on for sustaining extended deployments.
24 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-12.

Effects of Alternative 1B on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

This alternative would increase the active Army’s dependence on the reserve component slightly. The positions 

freed up by reducing support units would come disproportionately from reserve units (35,000 of the 50,000 

positions). Creating two new active-component divisions 

using those positions would require transferring about 

19,000 positions from active EAD support units to the 

reserve component. Because of that transfer of personnel, 

this alternative would require higher levels of reserve mobilization to support extended deployments (compared 

with either the current force or with Alternative 1A).

This option would improve the speed with which the 

Army could deploy forces overseas. Each division and its 

associated EAD support units would be slightly smaller 

and have less equipment to transport. With less equipment to move, units would be able to finish deploying 

faster than the current force could.

Implications for the Modular Army. Although this alternative was measured against the premodularity force 

structure, it would probably produce many of the same 

changes when applied to the Army’s new modular structure. Adding two modular divisions would increase the 

Army’s ability to fight wars (by providing additional combat forces) or sustain extended deployments (by increasing the pool of available units and personnel). Adding 

two modular divisions would also require additional personnel and would increase costs for investment, operations and support, and construction. The Army’s modular divisions will be larger than premodularity divisions 

and include four brigades (versus three), but CBO does 

not know what EAD support units those divisions will 

require. Some of the changes in the modular division, 

such as eliminating the divisional SHORAD battalion 

and returning to an eight-gun artillery battery, suggest 

that the Army may be able to create some of the additional brigades associated with modularity by eliminating 

support units in a fashion similar to this alternative.

Alternatives That Would Reduce

Dependence on the Reserve

Component

CBO’s second two alternatives illustrate the costs and 

effects associated with reducing the active Army’s dependence on mobilizing reserve units to support active 

combat units. That dependence has been the focus of sustained public and Congressional concerns since the midto late 1990s, when increased numbers of reserve personnel were mobilized to assist in a number of extended 

deployments (including Bosnia, Kosovo, and Operations

Personnel 285,000 -21,000

Brigades 20 No change

1.76 -0.15

109,000 -1,000

Active Army only 1.65 +0.3

Total Army 2.75 +0.3

First brigade 14 No change

First division 20 No change

First corps 53 -6

First theater 102 -7

Effects of Adding

Current Two Active Divisions

Force by Reducing Support Forces

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 25

Table 2-13.

Effects of Alternative 1B on the 

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

Northern Watch and Southern Watch to enforce the nofly zones over Iraq). The war on terrorism, particularly 

the occupation of Iraq, has greatly increased the levels of 

reserve mobilization needed to assist in military operations. That mobilization, however, is frequently disruptive and unwelcome to reserve personnel, can potentially 

interfere with the National Guard’s state missions, and is 

seen by some observers as inconsistent with the spirit and 

mission of the reserve components.

Alternatives 2 and 3 would both effectively eliminate the 

need to deploy reserve EAD units to support active combat units in sustained deployments. Alternative 2 would 

reallocate EAD support units between the active and reserve components, thus eliminating reserve mobilization 

for peacekeeping efforts, whereas Alternative 3 would create sufficient active EAD support units for the entire active force, thus eliminating reserve mobilization for both 

peacekeeping and major combat operations.

Implementing those alternatives, however, would not preclude several situations where reserve personnel would 

need to be mobilized, either for peacekeeping operations 

or for major combat operations. For example, the Army 

might need to mobilize National Guard combat forces for 

very stressful combat operations or for very large sustained deployments (as the Army is currently doing in 

Iraq). Further, as discussed previously, the Army routinely 

mobilizes reserve personnel to backfill for deployed 

active-duty units.

Alternative 2—Reallocate Support Forces Between 

the Active and Reserve Components 

This alternative would eliminate the active Army’s dependence on reserve support units for peacekeeping by shifting support units between the active and reserve components of the Army. Support units that are crucial in 

extended peacekeeping operations, such as military 

police, military intelligence, or civil affairs, would be 

transferred from the reserve component to the active 

component to minimize the need to mobilize reserve 

personnel to sustain extended deployments. To offset the 

shift in support units to the active component, units that 

are not essential to extended peacekeeping operations, 

such as field artillery, attack aviation, or air-defense artillery, would be transferred from the active component to 

the reserve component. Overall, this option would add 

about 28,000 active personnel to the Army and reduce 

reserve personnel by 24,000 (see Table 2-14).

This alternative would make a distinction between units 

that are needed to support extended deployments and 

those that are not. Historically, the Army has deployed 

about 40,000 personnel to a combat theater for every division it has deployed, reflecting the size of the full “slice” 

of support units the Army needs for high-intensity combat operations. In peacekeeping operations, however, 

which generally require less sustained combat, several 

forms of support units (primarily those intended to augment the firepower of combat divisions) are not as necessary. In addition, those operations place much lower 

demands on the Army’s logistics system and require fewer 

support units to provide adequate logistics supplies. 

(Peacekeeping operations also allow the Army to augment 

its logistics capabilities with civilian contractors.) Because 

all Army forces are tailored to their specific missions, 

however, the level of support forces that would be provided in any given peacekeeping operation may vary. The 

occupation of Iraq involves significantly more intense 

combat than the stabilization force in Kosovo, for example, and thus, Army units in Iraq receive more support 

units than those in Kosovo. CBO’s distinction between

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

+10,000–13,000 +10,000–12,000

+1.5–1.9 +1.5–1.9

+11,000–12,000 +10,000–11,000

Active Army

Only Total Army

Premodular Army

Brigades

Deployment

Personnel

Maximum Sustained

by Reducing Support Forces

Personnel Mobilized

Brigades

Personnel Mobilized

Deployment

Personnel

Reserve-Component

Reserve-Component

Maximum Sustained

Effects of Adding Two Active Divisions
26 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-14.

Effects of Alternative 2 on the Size 

and Composition of the Army

Source: Congressional Budget Office.

units needed only for warfighting and those needed for 

both peacekeeping and warfighting is intended to represent a typical level for sustained deployments.

In this alternative, the entire set of EAD units necessary 

to support active combat units in peacekeeping missions 

would be in the active component. The remaining EAD 

support units needed for those divisions, which would be 

primarily deployed for warfighting missions, would be 

entirely in the reserve component. This option would not 

change the level of reserve mobilization the Army would 

require for major combat operations (where both sets of 

units are needed) but would eliminate the need to mobilize reserve EAD support units for active combat forces to 

sustain extended deployments. Because the size of the set 

of EAD support units needed for active combat forces is 

larger than the number of personnel spaces available in 

the active component, this alternative would shift 20,000 

personnel spaces from the reserve component to the active component. Allowing for changes in the number of 

overhead positions required for the different component, 

this option results in an increase of 28,000 active personnel and a reduction of 24,000 reserve personnel.

Costs. Implementing this option would not change the 

Army’s investment program over the 2006-2022 period, 

since it would not create or eliminate any units—only 

shift units between components. The alternative would 

increase the Army’s operation and support costs by $27 

billion over that same period and by nearly $2 billion 

annually thereafter (see Table 2-15).

Effects. The primary benefit of this alternative would be 

to reduce the Army’s need to mobilize and deploy reserve 

personnel to support active combat forces in extended 

deployments. Its primary disadvantages would be the 

costs associated with adding active-component personnel, 

the need for potentially time-consuming reservecomponent mobilization of many types of EAD support 

units in wartime, and potential inefficiencies in the personnel process.

Implementing this option would have essentially no effect on the Army’s ability to either fight wars or sustain 

extended deployments (see Tables 2-16 and 2-17). It does 

not create or eliminate any units but instead swaps units 

between the active and reserve components, leaving the

Table 2-15.

Effects of Alternative 2 on the Cost 

of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

482,400 555,000 1,037,400

314

10 8 18

33 36 69

Supported 

brigades 33 22 55

+28,000 -24,000 +4,000

No change No change No change

No change No change No change

No change No change No change

Supported 

brigades No change No change No change

Active Reserve

Component Component Total Army

Total Brigades

Effects of Reallocating 

Active and Reserve Support Forces

Premodular Army

Personnel

Corps

Divisions

Corps

Divisions

Total Brigades

Personnel

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment No Change No Change No Change n.a.

Operation

and Support +9 +16 +27 +2 ___ ___ ___ __

Total +9 +16 +27 +2

2015 2022 2022

Active and Reserve Support Forces

Effects of Reallocating 

Premodular Army

2010

Annual

Total Costs Recurring

2006- 2006- 2006- Costs in
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 27

Table 2-16.

Effects of Alternative 2 on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

total Army’s set of units unchanged. The Army would 

still have access to all of the same combat divisions and 

the same set of support units.

This alternative would reduce the Army’s need to mobilize and deploy reserve personnel to support active units. 

For an extended deployment that used the entire active 

Army’s combat forces, the Army would need to mobilize, 

on average, 30,000 to 35,000 reserve personnel, compared with the 52,000 to 57,000 personnel the current 

force would need to mobilize (see Table 2-17). The vast 

majority of those mobilized personnel would provide 

backfill for deployed active units and would not be deployed overseas. The remaining reserve personnel, who 

would be mobilized and deployed for extended deployments, would be associated with National Guard special 

forces groups or other specialized communities and 

would not be needed to support active combat forces.10

This alternative would not reduce the Army’s need to mobilize reserve personnel to engage in major combat operations. For such operations, the Army would need to mobilize and deploy EAD support units from the reserve 

component for warfighting, and the number of personnel 

affected would be the same as for the current force.

This alternative would not directly affect deployment 

timelines, since the weight of the equipment that has to 

be transported is not affected by whether the unit is in 

the active or reserve component. But this option might 

indirectly affect deployment timelines because many 

types of support units would exist only in the reserve 

component, and reserve units typically require at least a 

month for mobilization. However, that situation is already the case under the Army’s current structure for 

some types of units (such as civil affairs units).

This option has the potential to cause some problems for 

the reserve personnel systems. Currently, the reserve components recruit former active-duty personnel, and such 

recruits (with prior service) make up a significant portion 

of the reserves’ personnel. Such personnel are attractive, 

in part, because they have already completed the military 

training the reserves require. However, if entire classes of 

units were concentrated in one component almost excluPersonnel 285,000 No change

Brigades 20 No change

1.76 No change

109,000 No change

Active Army only 1.65 No change

Total Army 2.75 No change

First brigade 14 No change

First division 20 No change

First corps 53 No change

First theater 102 No change

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel

Effects of Reallocating 

Current Active and Reserve

Force Support Forces

10. Special forces groups, for example, are not a required part of a 

combat division’s support package. Instead, they are employed 

independently. Employing those units is a separate policy decision 

from employing conventional combat units. Given the utility of 

special forces in stabilization and reconstruction missions, those 

forces would presumably be employed to sustain any extended 

deployment.
28 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-17.

Effects of Alternative 2 on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

sively, the reserve component would be less able to recruit 

prior service members with the appropriate training. Similarly, personnel with prior service would be less able to 

find a unit requiring skills that they already had and 

would need to be retrained, or they might find the idea of 

starting a new military specialty unappealing. CBO was 

unable to assess the likelihood or magnitude of that potential issue.

Implications for the Modular Army. Although this alternative was measured against the premodularity force 

structure, its reallocation of support forces to reduce the 

active Army’s dependence on the reserves may well apply 

to a modular Army. The Army has already been engaged 

in a limited rebalancing of support forces, for example, by 

retraining National Guard field artillery battalions as military police units. However, the Army has not announced 

details about the modular Army’s EAD support structure. 

If, as seems probable, the increased number of combat 

units in the modular Army forces the Army to rely more 

heavily on reserve combat forces, then the modular Army 

will require even more reserve personnel to be mobilized 

to support extended deployments. In that case, the modular Army would also benefit from reallocating support 

forces, but the number of personnel positions that would 

have to be transferred from the reserve to the active component would be even greater.

Alternative 3—Eliminate the Army’s Dependence 

on Reserve Support Units by Increasing the Size 

of the Active Army

This option would eliminate the active-component 

Army’s dependence on reserve-component support units 

for peacekeeping and warfighting by adding enough personnel to the active Army to create support units for all of 

its combat units. That action would effectively terminate 

the Total Force Policy and sever the tight operational 

linkage between components that the Army has maintained for the past three decades. Under this alternative, 

the active Army would be able to engage in the full range 

of military operations without needing to mobilize and 

deploy reserve personnel. Overall, implementing this 

option would add about 312,000 active personnel to the 

Army and eliminate 260,000 reserve personnel (see 

Table 2-18).

Table 2-18.

Effects of Alternative 3 on the Size 

and Composition of the Army

Source: Congressional Budget Office.

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

+1,000 +1,000

No change No change

-22,000 -22,000

Active Army

Brigades

Personnel Mobilized

Only Total Army

Personnel

Deployment

Personnel Mobilized

Reserve-Component

Reserve-Component

Maximum Sustained

Personnel

Brigades

Deployment

Maximum Sustained

Premodular Army

Effects of Reallocating

Active and Reserve Support Forces

482,400 555,000 1,037,400

3 14

10 8 18

33 36 69

Supported 

brigades 33 22 55

+312,000 -260,000 +52,000

+1 -1 No change

No change No change No change

+2 -1 +1

Supported 

brigades +2 -1 +1

Corps

Divisions

Total Brigades

Total Brigades

Effects of Increasing the

Personnel

Premodular Army

Personnel

Corps

Divisions

Active Army's Size

Active Reserve

Component Component Total Army
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 29

Table 2-19.

Effects of Alternative 3 on the Cost 

of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

In this alternative, the size of the active Army would be 

increased to create the entire set of warfighting and peacekeeping EAD units needed to support active Army combat units. The corresponding reserve-component EAD 

units that were previously intended to support active 

units would be eliminated. In addition, this option 

would:

B Transfer all units associated with I Corps from the 

reserve component to the active component.

B Transfer the 278th Armored Cavalry Regiment from 

the reserve component to the active component.

B Convert the 11th Armored Cavalry Regiment from a 

mixed-component unit to a fully active-component 

unit.

B Transfer both National Guard special forces groups 

from the reserve component to the active component.

Those transfers would result in an active Army with four 

active corps, an active ACR for each corps, and 35 fully 

supported combat brigades, all with active-component 

support units.

Costs. Implementing this option would not change the 

Army’s investment program over the 2006-2022 period, 

since it would not create or eliminate any units. It would 

increase the Army’s O&S costs by about $333 billion 

over the same period and by about $26 billion annually 

thereafter (see Table 2-19).

The primary benefit of this alternative would be to eliminate the Army’s need to mobilize and deploy reserve personnel to support active combat forces, either for major 

combat operations or in extended deployments. Its primary disadvantage would be the costs associated with 

adding active-component personnel.

Effects. This option would not change the Army’s ability 

to fight wars. It would not create or eliminate any units 

but instead swap units between the active and reserve 

components, leaving the total Army’s set of units 

unchanged (see Table 2-20). The Army would still have 

access to all of the same combat divisions and the same 

set of support units.11

However, this option would improve the Army’s ability to 

support extended deployments (see Table 2-21). The 

number of soldiers the Army can sustain in extended deployments is limited by the policy that reserve personnel 

cannot be deployed as frequently as active-component 

personnel can be. In this option, transferring a corps, the 

ACRs, and the special forces groups to the active component allows those units to rotate through deployments at 

the higher rate for active personnel rather than the lower 

rate for reserve personnel.

This alternative would eliminate the Army’s need to 

mobilize and deploy reserve personnel to support active 

units. For an extended deployment that used the entire 

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment No Change No Change No Change n.a.

Operation 

and Support +51 +158 +333 +26 ____ ____ ____ ___

Total +51 +158 +333 +26

Active Army's Size

Effects of Increasing the

Premodular Army

2010

Annual

Total Costs Recurring

2015 2022 2022

2006- 2006- 2006- Costs in

11. The net increase of one combat brigade in this option reflects converting the 11th ACR to a fully active unit. Currently, the 11th 

ACR has an active portion, which normally is assigned the mission of Opposing Force at the Army’s National Training Center, 

and a reserve-component support portion. Because of that mission 

and structure, CBO followed Army practice and did not generally 

count the 11th ACR as a combat unit. In this option, however, 

the unit would be converted to a fully active unit capable of being 

employed in the same manner as any other ACR. CBO transferred the ACRs to the active component to allow the active Army 

to have the one ACR per corps that Army doctrine requires.
30 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-20.

Effects of Alternative 3 on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

active Army’s combat forces, the Army would need to 

mobilize, on average, 22,000 to 27,000 reserve personnel, 

compared with the 52,000 to 57,000 personnel the current force would need to mobilize (see Table 2-21). All 

the personnel who were mobilized would be used to provide backfill for deployed active units and would not be 

deployed overseas.

If the Army needed to mobilize and deploy National 

Guard combat forces, either for a very stressful major 

combat operation or to sustain a very large extended 

deployment, it would still need to mobilize and deploy 

reserve personnel. But even under those circumstances, 

the number of reserve personnel mobilized and deployed 

would generally be greatly reduced from the levels associated with the current force.

This alternative would not directly affect deployment 

timelines because the weight of the equipment that has to 

be transported would be the same whether the unit was 

in the active or reserve component. This option might 

indirectly affect deployment timelines, however, because 

it places all EAD support units for active forces in the 

active component, thus eliminating the need for potentially time-consuming post-mobilization activities. However, the Army has been able, in the past, to deploy active 

support units first and complete post-mobilization activities for reserve units in a timely manner. Therefore, the 

link between the time required to mobilize reserve units 

and the time required to deploy Army forces is unclear.

Implications for the Modular Army. Although this alternative was measured against the premodularity force 

structure, the creation of a full set of active support forces 

to eliminate the active Army’s dependence on the reserve 

component would also be possible under the Army’s new 

modular structure. Although the Army has not announced details of the modular Army’s EAD support 

structure, the modular Army will have more active combat units and thus will probably need to rely more heavily 

on reserve combat forces to support major combat operations or extended deployments. As such, the modular 

Army would also benefit from having a full set of active 

support forces, but the size of the increase in the number 

of active personnel positions that would be required to 

establish those units (and the corresponding decrease in 

the number of reserve-personnel positions that would be 

required) would be even greater.

This alternative would eliminate the active Army’s dependence on the reserve component by adding sufficient personnel to the active Army to allow it to create a full set of 

EAD support units for all of its combat units. It does so 

while holding the active combat unit force structure conPersonnel 285,000 No change

Brigades 20 No change

1.76 No change

109,000 -109,000

Active Army only 1.65 +0.1

Total Army 2.75 +0.05

First brigade 14 No change

First division 20 No change

First corps 53 No change

First theater 102 No change

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel

Current Effects of Increasing

Force the Active Army's Size
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 31

Table 2-21.

Effects of Alternative 3 on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

stant. Conversely, a potential variation on this option 

would remove enough combat units from the Army’s 

force structure to eliminate the active Army’s dependence 

on the reserves while holding the number of personnel in 

the Army constant. If the option were implemented in 

that way, the Army would have to eliminate one active 

corps, four active divisions, and 13 active combat brigades. Although CBO did not examine the costs and full 

effects of that approach, such cuts in combat forces available to the Army would produce significant reductions in 

the Army’s ability to conduct major combat operations or 

sustain extended deployments.

Alternatives That Would Create 

New Types of Units

The last four alternatives all restructure the Army but in 

ways that emphasize different types of units and thus 

reflect a variety of concerns and proposals. The Army has 

frequently reorganized its units in the past, creating new 

types of units or engaging in large-scale organizational 

reform. Such reorganizations are generally associated with 

either evolving concepts about how to best fight wars or 

changes in U.S. military strategy that emphasize different 

potential opponents or types of wars.12 In recent years, 

public debate and various defense experts have considered 

potential reorganizations that would improve various 

aspects of the Army in response to perceived shifts in warfighting methods and national strategies.

The Army’s current modularity reorganization is one version of plans to restructure the Army by creating new 

types of units. To some degree, all of the options CBO 

examined present ways to reorganize the Army by creating different, nonmodular types of units. However, modular units will have many similarities to current units, and 

all of the restructuring plans CBO analyzed have elements that would also be applicable to a modular Army.

The last four alternatives CBO analyzed are intended to 

show how the Army could be restructured with new units 

to meet different visions of how future conflicts will be 

waged and what types of conflicts the United States may 

need to engage in. Alternative 4, which would create 

peacekeeping divisions, is intended to illustrate the potential to restructure the Army to focus more on stabilization and reconstruction missions. Such missions have 

consumed a large and increasing share of the Army’s 

forces in recent years and are arguably central to current 

U.S. national strategy. Alternative 5, which attempts to 

implement the ideas of retired Army Colonel Douglas 

MacGregor by creating a brigade-based Army, is intended 

to illustrate the potential for the heavy forces of today’s 

Army to operate more rapidly and more independently. 

Those ideas were arguably influential in the Army’s current modularity plan and respond to the perception that 

the Army’s heavy forces are not well suited to the fast pace 

of modern warfare. Alternative 6, which would create 

expeditionary forces, is intended to illustrate the potential 

to greatly improve the speed with which the Army can 

deploy to distant theaters. The time required to deploy 

U.S. forces has been of concern to DoD and many defense experts since Operation Desert Storm, and reducing 

that time is widely considered to be crucial to future U.S. 

strategy. Finally, Alternative 7, which would create trans89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

+10,000–12,000 +9,000–11,000

+0.5–0.6 +0.4–0.5

-30,000 -32,000

Deployment

Personnel

Active Army

Effects of Increasing the

Active Army's Size

Premodular Army

Only Total Army

Maximum Sustained

Personnel Mobilized

Personnel Mobilized

Brigades

Deployment

Personnel

Brigades

Reserve-Component

Reserve-Component

Maximum Sustained

12. Combat Studies Institute, Sixty Years of Reorganizing for Combat: 

A Historical Trend Analysis, Report No. 14 (Fort Leavenworth, 

Kan.: U.S. Army Command and General Staff College, December 

1999); and John B. Wilson, Maneuver and Firepower: The Evolution of Divisions and Separate Brigades, Army Lineage Series 

(Washington, D.C.: U.S. Army Center of Military History, 

1998). 
32 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-22.

Effects of Alternative 4 on the Size 

and Composition of the Army

Source: Congressional Budget Office.

Note: S&R = stabilization and reconstruction.

formational forces, is intended to illustrate what a small, 

light force that depends on long-range, precision-guided 

firepower would look like. Those attributes form some of 

the core themes of the idea of military transformation 

that has become central to most debates about the future 

of the U.S. military.

Alternative 4—Organize Stabilization and

Reconstruction Divisions

This option would convert two active Army divisions 

into dedicated peacekeeping divisions. It is based on a 

proposal from the National Defense University that describes the organization and structure of a potential stabilization and reconstruction (S&R) division.13 Those 

S&R divisions would include military police, engineer, 

medical, civil affairs, and psychological operations units, 

all of which have been in high demand for peacekeeping 

operations, along with a single medium-weight Stryker 

brigade. This option would eliminate one heavy and one 

light infantry division from the active component (along 

with their associated EAD support units) and would create four active-component S&R divisions and one reserve 

component S&R division. Overall, implementing this 

option would reduce the Army’s active personnel by 

2,000 and reserve personnel by 9,000 (see Table 2-22).

Costs. Implementing this option would reduce the costs 

for the Army’s investment program by $14 billion over 

the 2006-2022 period, since the Army would have fewer 

combat divisions that would need to be modernized. It 

also would reduce the Army’s O&S costs by $18 billion 

over the same period and by about $1 billion annually 

thereafter because the S&R divisions would have lower 

costs than combat divisions do (see Table 2-23).

The primary benefit of this alternative would be to provide the Army with dedicated peacekeeping forces specializing in the sorts of missions associated with extended 

deployments. Its primary disadvantage would be the reduction in combat forces. 

Table 2-23.

Effects of Alternative 4 on the Cost 

of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable; S&R = stabilization and reconstruction.

13. Hans Binnendijk and Stuart Johnson, eds., Transforming for Stabilization and Reconstruction Operations (National Defense University, Center for Technology and National Security Policy, 

November 12, 2003).

482,400 555,000 1,037,400

3 14

10 8 18

33 36 69

Supported 

brigades 33 22 55

-2,000 -9,000 -11,000

No change No change No change

-2 No change -2

-6 No change -6

Supported 

brigades -6 No change -6

Active Reserve

Component Component Total Army

Effects of Organizing S&R Divisions

Personnel

Premodular Army

Personnel

Corps

Divisions

Corps

Divisions

Total Brigades

Total Brigades

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment +2 -3 -14 n.a.

Operation

and Support -4 -10 -18 -1 __ __ __ __

Total -2 -13 -32 -1

Effects of Organizing S&R Divisions

Premodular Army

2010 2015 2022 2022

Annual

Total Costs Recurring

2006- 2006- 2006- Costs in
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 33

Table 2-24.

Effects of Alternative 4 on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

Note: S&R = stabilization and reconstruction.

Effects. With fewer divisions and combat brigades, the 

Army would be less capable of fighting multiple wars simultaneously (see Table 2-24). It also might have to send 

fewer forces to any given conflict. Alternatively, if the 

Army had significant peacetime commitments, it might 

have to abandon some of those commitments during a 

conflict because of high-priority combat needs.

This option would slightly increase the Army’s ability to 

sustain extended deployments for peacekeeping missions 

(see Table 2-25). The additional S&R divisions increase 

the pool of personnel and units available for rotations to 

extended deployments, but that increase only slightly offsets the decrease produced by eliminating two combat divisions and their EAD support units. The overall size of 

the Army would not change significantly in this option; 

the increase in personnel that the Army could sustain on 

extended deployments comes from converting EAD support units that would not have been used in peacekeeping 

into S&R units that would be. However, since such units 

form only a fraction of all of the units involved in two 

combat divisions and their full set of EAD support units, 

the benefit of converting them is limited.

The mix of soldiers and units in each S&R division might 

be qualitatively superior to the Army’s current combat 

forces for peacekeeping missions, given their specialties 

and the historic demand for such types of units in those 

missions. Historically, the Army has treated S&R missions as a limited subset of the full range of missions that 

combat units may face and must be prepared to conduct. 

However, many observers and military personnel have 

argued that the missions and equipment of many combat 

units are inappropriate for S&R missions, which frequently require skills similar to those of police forces. 

They believe the Army’s more powerful combat units, 

with their heavy armor and firepower, are poorly suited to 

patrol neighborhoods, develop contacts with the local civilian population, provide essential services (such as public works), or conduct other duties associated with peacekeeping. In contrast, units such as civil affairs (which are 

trained to establish basic governing structures for occupied civilian populations) or construction engineers 

(which are trained to engage in various construction and 

civil engineering tasks) are more useful in peacekeeping 

settings than armored battalions. However, S&R missions historically have stressed establishing secure conditions in an area as the precondition for successful stabilization and reconstruction efforts. In this view, the Army’s 

combat units are more capable of establishing secure conditions than are support units, which often require combat units to protect them in insecure environments. CBO

Personnel 285,000 No change

Brigades 20 No change

1.76 No change

109,000 No change

Active Army only 1.65 -0.3

Total Army 2.75 -0.3

First brigade 14 No change

First division 20 No change

First corps 53 No change

First theater 102 No change

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel

Current Effects of Organizing

Force S&R Divisions
34 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-25.

Effects of Alternative 4 on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

Note: S&R = stabilization and reconstruction.

was unable to quantitatively assess what mix of types of 

units might be most effective in peacekeeping.

This option would produce a slight decrease in the level 

of reserve mobilization needed to sustain extended deployments, since each active S&R division could be deployed without the reserve support units associated with 

combat divisions. However, that reduction would be lessened if the Army needed to mobilize and deploy the

reserve-component S&R division.

Adding peacekeeping divisions to the Army would not 

affect the ability of Army forces to deploy. Although the 

S&R divisions are structured differently from Army combat forces—for example, they have less equipment to 

transport—S&R divisions would not be sent to a major 

combat operation. Such formations might be deployed 

after a major combat operation or even during combat 

operations, but the speed with which the Army could 

deploy any given set of combat units to a theater would 

not be affected by the composition of the follow-on S&R 

divisions.

Implications for the Modular Army. Although this alternative was measured against the premodularity force 

structure, its creation of dedicated peacekeeping formations by eliminating some combat formations would also 

be possible for a modular Army. Since the Army’s modular divisions will be larger than premodularity divisions, a 

modular Army would be able to create slightly more S&R 

forces by eliminating combat forces, but the overall effect 

of trading combat forces for peacekeeping forces would 

be similar.

Alternative 5—Convert to a Brigade-Based Army

This option would reorganize the Army in the manner 

suggested by Colonel MacGregor by eliminating higherlevel command structures and organizing the Army into a 

number of autonomous brigade-sized combat groups.14

It would eliminate divisions and corps (and the traditional support structures associated with them) and create 

a set of 25 large, semiautonomous, brigade-sized combat 

groups for the active component. Types of support currently provided by higher-echelon formations would instead come from a mix of support groups. This alternative would not change the number of active personnel in 

the Army but would reduce reserve personnel by 383,000 

(see Table 2-26).

This option would eliminate all currently existing divisions and brigades, all corps, and the Army’s theater-level 

structures. It would replace those units with the following 

units (all composed entirely of active personnel):

B Three light reconnaissance strike groups, similar to the 

light cavalry configuration of the Army’s 2nd ACR;

B Nine airborne/air assault groups similar to brigades of 

the Army’s 101st Air Assault Division;

B Thirteen combat maneuver groups, similar to the 

heavy cavalry configuration of the Army’s 3rd ACR;

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

+1,000 +2,000–3,000

-1.5–1.9 -1.5–1.9

-3,000–4,000 -1,000–2,000

Effects of Organizing S&R Divisions

Only Total Army

Deployment

Personnel

Maximum Sustained

Premodular Army

Active Army

Personnel Mobilized

Personnel Mobilized

Brigades

Deployment

Personnel

Brigades

Reserve-Component

Reserve-Component

Maximum Sustained

14. Douglas A. MacGregor, Breaking the Phalanx: A New Design for 

Landpower in the 21st Century (Westport, Conn.: Praeger Publishers, 1997), and Transformation Under Fire: Revolutionizing How 

America Fights (Westport, Conn.: Praeger Publishers, 2003). It 

should be noted that this alternative addresses only a relatively 

small subset of the reforms Colonel MacGregor proposes. CBO 

was unable to evaluate the extensive discussion of changes in 

Army warfighting doctrine, culture, or personnel policies that 

Colonel MacGregor believes would be at least as important as, if 

not much more important than, the organizational changes discussed in this study.
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 35

Table 2-26.

Effects of Alternative 5 on the Size 

and Composition of the Army

Source: Congressional Budget Office.

Note: n.a. = not applicable.

B Nine aviation combat groups, similar to the Army’s 

corps-level aviation brigades;

B Six air-and-missile-defense groups, equipped with

Patriot and Terminal High Altitude Area Defense 

missile;

B Six command-and-intelligence groups—composite 

units with signals, military intelligence, and psychological operations units;

B Three chemical-response groups, intended to help 

respond to biological or chemical warfare;

B Three early-deploying support groups, to provide 

logistics functions;

B Four engineer groups, to provide engineering support; 

and

B Five late-deploying support groups, to provide more 

robust logistics functions.

This option would also create the following units in the 

reserve component:

B Two air assault groups;

B Two combat maneuver groups;

B Five aviation groups;

B One air-and-missile-defense group;

B One command-and-intelligence group;

B Two engineer groups; and

B Five later-deploying support groups.

Because this option would create a full set of combat and 

support units using active-personnel positions freed up 

by eliminating the active Army’s existing units, active 

combat forces would not need to rely on reserve EAD 

support forces.15

All of the combat groups in this alternative are larger, but 

more autonomous, than current combat brigades. Under 

this alternative, the Army would structure a combat force 

with a relatively small headquarters element commanding 

a collection of combat groups and a mix of support 

groups appropriate to the situation. That structure would 

be smaller and more flexible than current combat forces, 

which require division- and corps-level headquarters and 

layers of support units and which maintain many essential support functions at a relatively high command level. 

However, with 25 active maneuver brigades—CBO considered only the first three types of groups as combat 

units, the remaining groups being analogous to current 

EAD support units—that force would have fewer combat 

brigades than the current Army does.

In addition to the organizational changes outlined in this 

option, CBO chose to change the Army’s investment 

program considerably. MacGregor’s work illustrates how 

482,400 555,000 1,037,400

3 14

10 8 18

33 36 69

Supported 

brigades 33 22 55

No change -383,000 -383,000

n.a. n.a. n.a.

n.a. n.a. n.a.

-8 -32 -40

Supported 

brigades -8 -18 -26

Corps

Divisions

Total Brigades

Total Brigades

Effects of Converting to a 

Personnel

Premodular Army

Personnel

Corps

Divisions

Brigade-Based Army

Active Reserve

Component Component Total Army

15. Colonel MacGregor does not discuss the composition of the 

reserve component extensively in his published material. The 

composition of the reserve forces specified above is CBO’s best 

estimate of the type of forces that Colonel MacGregor has explicitly advocated, but it is possible that his proposal would include a 

more robust set of reserve units to deal with missions such as 

homeland security that are not the primary focus of his work and, 

as such, are not discussed extensively.
36 OPTIONS FOR RESTRUCTURING THE ARMY

the Army’s current heavy forces, with the combination of 

the M1 Abrams tank and M2/3 Bradley infantry fighting 

vehicles, can be made more deployable, flexible, and lethal. As such, the Army’s Future Combat Systems program, which is intended to produce similar effects, might 

not be necessary if this option achieved its goals. To reflect that possibility, this option would terminate the FCS 

program and replace it with various initiatives to rebuild, 

remanufacture, and upgrade the Army’s heavy equipment. Among other things, the investment program in 

this option would:

B Continue the Abrams tank conversions under the 

M1A2 system enhancement program at a steady-state 

rate indefinitely into the future;16

B Continue the upgrades under the Abrams common 

engine program until the entire tank fleet had received 

new engines;

B Continue various programs to remanufacture and 

upgrade the M2/3 Bradley fighting vehicle at a steadystate rate indefinitely into the future;

B Restart the program to upgrade the M270A2 

multiple-launch rocket system and modernize all of 

the Army’s rocket-launcher artillery platforms;

B Continue the program to upgrade the AH-64D Longbow and modernize all of the Army’s attack helicopters; and

B Continue the program to remanufacture the UH-60

L/M Blackhawk helicopter at a steady-state rate indefinitely into the future.

The cumulative effect of those conversion and remanufacturing programs would be to maintain the Army’s current fleet of heavy armored vehicles and helicopters in a 

viable state for the indefinite future while continuing several low-cost evolutionary upgrades that would maintain 

U.S. forces’ technological superiority over potential opponents.17

Table 2-27.

Effects of Alternative 5 on the Cost 

of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

The primary benefit of this alternative would be to provide the Army with more flexible and autonomous combat forces that could be deployed more rapidly. Its primary disadvantage would be a reduction in the number 

of combat forces available to the Army.

Costs. CBO estimates that implementing this option 

would reduce the costs for the Army’s investment program by $176 billion over the 2006-2022 period, primarily as a result of terminating the FCS program but also 

because the Army would have fewer combat forces to 

modernize. It also would reduce the Army’s O&S costs by 

about $138 billion through 2022 and by $10 billion annually thereafter (see Table 2-27).

16. The steady-state rate is the rate at which all of the Army’s platforms would be converted or remanufactured frequently enough 

to stabilize the average age of the fleet at half of the desired service 

life for the platform.

17. Some supporters of the FCS might argue that this alternative 

would fail to advance U.S. technological superiority over its 

potential opponents significantly. However, opponents of the 

FCS could note that many elements of the Army’s plan for the 

FCS appear well suited for high-end conventional warfare but 

largely irrelevant for missions such as suppressing insurgencies, 

which may become more important to the Army in the future.

129 334 605 n.a.

398 826 1,488 99

___ ____ ____ ___

Total 527 1,160 2,092 99

-14 -78 -176 n.a.

-28 -71 -138 -10

__ ___ ___ __

Total -42 -149 -314 -10

and Support

Effects of Converting to a

Investment

Operation 

Brigade-Based Army

Premodular Army

Investment

Operation 

and Support

2010 2015 2022 2022

2006- 2006- 2006- Costs in

Annual

Total Costs Recurring
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 37

Table 2-28.

Effects of Alternative 5 on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

Effects. With fewer combat brigades in this option, the 

total Army would be less capable of fighting multiple 

wars simultaneously (see Table 2-28).18 It also could have 

to send fewer forces to any one conflict. Alternatively, if 

the Army had significant peacetime commitments, it 

might have to abandon those commitments during a conflict because of the reduced number of combat forces 

available.

A brigade-based Army would also have a smaller pool of 

personnel and units to draw on for sustaining extended 

deployments (see Table 2-29). As such, it would be less 

capable of sustaining larger numbers of personnel or 

combat brigades through rotational deployments. The 

reduction in forces available in this option would be 

roughly equivalent to about three to four commitments 

the size of the current U.S. commitment to Afghanistan.

Supporters of this option would argue that although it 

would decrease the overall number of combat brigades in 

the active Army, it would improve the Army’s ability to 

fight wars overall. Colonel MacGregor suggests that such 

forces would be able to deploy faster and engage in fastmoving operations that would overwhelm conventional 

enemies with far fewer forces than current structures require. CBO was not able to assess such claims about the 

qualitative improvement in warfighting that a brigadebased Army might provide. However, to illustrate the potential of such an effect, CBO assumed that the brigadebased Army could deploy a corps-sized force of six combat brigades (as opposed to 10 for the current force) and a 

theater-sized force of 12 combat brigades (as opposed to 

20 for the current force). If that were the case, then under 

this option, the active Army would be capable of prosecuting nearly as many conflicts simultaneously, even 

though it had far fewer combat brigades. Even with that 

assumption, however, this option’s large reduction in 

National Guard combat forces would mean that the total 

Army would still be less capable of fighting multiple wars 

simultaneously.

Detractors of this option might argue that the Army 

would be structured with small, possibly inadequately 

supported combat forces. Some observers do not believe 

that it would be plausible to engage in sustained combat 

operations with such limited levels of support; others 

argue that attempting to do so would incur an unacceptable level of risk. Historically, the Army’s combat divisions, along with their EAD support units and slice of

Personnel 285,000 -166,000

Brigades 20 -8

1.76 -0.85

109,000 -109,000

Active Army only 1.65 +0.43

Total Army 2.75 -0.33

First brigade 14 +2

First division 20 0

First corps 53 -26

First theater 102 -49

Current Effects of Converting to a

Force Brigade-Based Army

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel

18. The Army would be less capable of fighting wars if it experienced 

no qualitative improvement in the ability of each brigade. Supporters of this option would argue that it would produce such an 

effect. 
38 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-29.

Effects of Alternative 5 on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

corps and theater assets (in other words, the size of the 

corps or theater divided up among the subordinate divisions), have each required about 40,000 personnel in a 

theater, suggesting that the Army has, in the modern era, 

always required more than one EAD support soldier for 

every one divisional combat soldier (varying between 

1.3:1 and 1.7:1, depending on the type of division).19

This option would reduce that EAD ratio to slightly 

more than 0.9:1, much lower than any other option in 

this paper. Although some observers consider that level to 

be unrealistically low, others have been enthusiastic about 

MacGregor’s restructuring proposal.

Detractors of this option also might note that MacGregor’s plan assumes that the Army would be capable of 

eliminating the theater level of command, which performs a number of functions important to other military 

services operating in a theater (such as seaport operations). If that plan was implemented, the other services 

might need to be enlarged to compensate for the lack of 

support from the Army. In addition, because many 

theater-level tasks are currently assigned to the Army as 

part of its legal roles and missions, changes to those tasks 

would require revisions to title 10 of the U.S. Code.

Because the combat and support groups created in this 

option are entirely active-component units, it would 

make the active Army much less dependent on reserve 

EAD support units, whether for peacekeeping or for 

warfighting missions. The Army might still choose to 

mobilize some reserve personnel for major combat operations and would still mobilize some reserve personnel for 

peacekeeping operations (such as National Guard special 

forces groups), but in general, unless the Army needed to 

mobilize National Guard combat forces, reservecomponent mobilization in this option would be minimal.

Converting to a MacGregor-style brigade-based Army 

would generally make the Army easier to deploy. Although at the level of a single brigade, the brigade-based 

Army would take longer to deploy (since each brigade 

would be larger and have more equipment), deploying a 

force equivalent to a division, corps, or theater would be 

faster. The increased speed would result partly because 

the corps- and theater-sized forces in this option would 

be smaller and partly because they would not need to 

deploy division- and corps-level command echelons and 

the large number of support units associated with them. 

When current forces are deployed, the units associated 

with a corps or a theater have about as much equipment 

and personnel as an entire heavy division with all of its 

supporting units. A brigade-based force that would not 

require deploying a corps (and did not include equivalent 

elements) would have much less equipment to transport 

and could be deployed more rapidly.

Implications for the Modular Army. Although this alternative was measured against the current force structure, 

converting the modular Army to a MacGregor-style 

brigade-based Army would produce essentially the same 

effects because the core of this option is to eliminate all of 

the Army’s existing units and create an entirely new set of 

units. However, many elements of the Army’s current 

modularity plan are similar to the brigade-based Army, 

including the emphasis on more-autonomous brigades, 

the creation of more-flexible division structures, and the 

decision to merge the corps and theater levels of com19. That level will tend to be lower for actual forces sent to actual conflicts, where the Army can tailor a force to meet the specific mission. In contrast, Army planning numbers tend to assume that the 

Army must have sufficient forms of support to engage in all 

potential missions, a considerably more demanding goal.

Total Army

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

-20,000–25,000 -37,000–45,000

-2.0–2.5 -5.6–6.8

-43,000–44,000 -68,000–69,000

Deployment

Personnel

Maximum Sustained

Active Army

Effects of Converting to a

Brigade-Based Army

Premodular Army

Only

Personnel Mobilized

Personnel Mobilized

Brigades

Deployment

Personnel

Brigades

Reserve-Component

Reserve-Component

Maximum Sustained
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 39

mand into one echelon. Nonetheless, the Army’s modularity plan creates a larger number of smaller brigades (as 

opposed to this alternative’s creation of a smaller number 

of larger brigades) and retains some of the command levels that MacGregor would simply eliminate.

Because this alternative would greatly reduce the reserve 

component’s need for personnel positions, it would allow 

for a number of variations using those personnel positions—for example, restoring the theater level of command or increasing the number of National Guard combat units. Using personnel in those ways would decrease 

the cost savings that might be achieved by this alternative, 

but it would also increase the Army’s overall ability to 

fight wars and to sustain extended deployments. For 

example, all of the National Guard’s current major combat formations (and sufficient EAD units to fully support 

them) could be retained, thus significantly reducing the 

overall decrease in combat forces. If this option was modified in that manner, it would result in about 10,000 

fewer reserve-component personnel than the current 

force has (as opposed to 383,000 fewer personnel), thus 

costing more but having about the same number of combat brigades as the current force.

Alternative 6—Convert to an Expeditionary Army

This alternative illustrates how the Army might be able to 

improve its deployment speed by adopting some organizational structures and practices used by the Marine 

Corps. It would eliminate the corps as a command structure, reorganize the Army into a series of expeditionary 

forces (similar to Marine expeditionary forces), and purchase additional sealift assets and additional sets of equipment that would be prepositioned on ships near potential 

theaters of conflict. Overall, this option would add 

21,000 active personnel and 20,000 reserve personnel to 

the Army (see Table 2-30).

The Marine Corps does not employ a corps or theater 

level of command for its units. Instead, Marine Corps 

units are organized into a series of Marine air-ground task 

forces. Each task force has a command element (normally 

a small headquarters), a ground-combat element, an aircombat element, and a combat-service-support element. 

The task forces are distinguished by the size of the 

ground-combat element. The largest type of task force is 

the Marine expeditionary force, with a division, an air 

wing, and a force-service-support group.20 Marine divisions, unlike Army divisions, are composed almost 

Table 2-30.

Effects of Alternative 6 on the Size and 

Composition of the Army

Source: Congressional Budget Office.

Note: n.a. = not applicable.

entirely of combat units, with support units (such as 

aviation or logistics) in the air-combat or combat-servicesupport elements.

In this option, Army forces would be structured in a 

manner similar to Marine expeditionary forces. Because 

the Army maintains both heavy and light forces (unlike 

the Marines), there would be separate types of light expeditionary forces and heavy expeditionary forces. Each 

expeditionary force would include:

B A command element, with headquarters and signals 

units;

20. The Air Force also has recently developed air expeditionary forces, 

which are intended to combine different types of aircraft together 

into a single, easily deployed force. Since Navy ships are, in 

essence, also self-contained expeditionary forces, this option 

would bring the Army’s forces more in line with the broader direction of all of the military services.

482,400 555,000 1,037,400

314

10 8 18

33 36 69

Supported 

brigades 33 22 55

+21,000 +20,000 +41,000

n.a. n.a. n.a.

-1 -2 -3

+3 -2 +1

Supported 

brigades +3 +12 +15

Corps

Divisions

Total Brigades

Total Brigades

Effects of Converting to an

Personnel

Premodular Army

Personnel

Corps

Divisions

Expeditionary Army

Active Reserve

Component Component Total Army
40 OPTIONS FOR RESTRUCTURING THE ARMY

B A ground-combat element, equivalent to a division 

with four combat brigades;21

B An air-combat element, with six to 11 battalions of 

helicopters, maintenance units, and Patriot missile 

units; and

B A support group, with engineer, military police, military intelligence, medical, and logistics units.

A heavy expeditionary force would have two armored and 

two mechanized infantry brigades in its division and a 

smaller aviation group emphasizing attack helicopters. It 

would have about 43,000 personnel. A light expeditionary force would have three light brigades and one Stryker 

brigade in its division and a larger aviation group emphasizing reconnaissance, utility, and cargo helicopters. It 

would have about 39,000 personnel.22

In this option, the active Army would have five heavy and 

four light expeditionary forces, and the National Guard 

would have four heavy and two light expeditionary 

forces. The option would also retain the Army’s current 

theater structure and 10 of the National Guard’s current 

separate brigades. All of the National Guard forces would 

be fully supported combat forces, with sufficient EAD 

support units to simultaneously deploy all National 

Guard combat units to combat operations. As in the current force, active expeditionary forces would depend on 

reserve support units (which would be part of the expeditionary forces), although to a somewhat more limited 

degree than the current force does.

Finally, this alternative would greatly expand the Army’s 

current program of prepositioning sets of equipment on 

board ships stationed near potential theaters. Prior to 

Operation Iraqi Freedom, the Army used eight large,

medium-speed roll-on/roll-off ships (LMSRs) to store a 

single heavy brigade’s worth of combat equipment and 

equipment for some theater-level units in the Indian 

Ocean.23 Currently, the Army is moving toward using six

Table 2-31.

Effects of Alternative 6 on the

Cost of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

LMSRs to establish three flotillas, each with a single 

heavy brigade’s worth of combat equipment, in the Mediterranean Sea, Indian Ocean, and Pacific Ocean. This 

alternative would expand the size of those flotillas, and 

the shipping capacity available to DoD, by purchasing 20 

additional LMSRs (doubling the size of Military Sealift 

Command’s LMSR fleet). Some of those LMSRs would 

be used to establish larger flotillas, each carrying two 

heavy brigades’ worth of equipment. The remainder 

would be used to transport equipment from the United 

States to combat theaters.

In addition to the organizational changes outlined in this 

option, CBO chose to change the Army’s investment program considerably. Because this alternative would greatly 

increase the speed with which the Army could deploy its 

21. Marine Corps divisions do not have four subordinate combat bri- forces, as in the previous option, the Army’s FCS progades but do contain a higher fraction of maneuver units than 

Army divisions do. CBO approximated the larger number of 

maneuver units by adding a fourth brigade to each division in this 

alternative. 

22. Along with the theater structure, this alternative would maintain 

the Army’s level of support at the lower end of the historical range 

of about 1.3 EAD support personnel for every divisional soldier.

23. LMSRs are very large cargo ships designed to transport vehicles. 

They are sometimes described as floating parking garages. They 

are the preferred type of ship for transporting most Army units’ 

equipment, as the majority of Army vehicles cannot be shipped in 

the standard shipping containers that dominate the civilian shipping market.

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment +25 -17 -79 n.a.

Operation

and Support +10 +23 +45 +3 ___ ___ ___ __

Total +35 +6 -34 +3

Expeditionary Army

Effects of Converting to an

Premodular Army

2010 2015 2022 2022

Annual

Total Costs Recurring

2006- 2006- 2006- Costs in
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 41

Table 2-32.

Effects of Alternative 6 on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

gram, which is intended to produce similar effects, might 

not be necessary if this option achieved its goals. To reflect that possibility, this option would terminate the FCS 

program and replace it with a series of various programs 

to rebuild, remanufacture, and upgrade the Army’s current heavy equipment. Those programs are the same as in 

the previous alternative, but because this alternative 

would establish an Army force structure with more heavy 

combat vehicles (for the larger number of heavy brigades 

and the additional sets of prepositioned equipment), 

those programs would have larger annual purchase requirements, offsetting more of the savings from canceling 

the FCS.

The primary benefit of this alternative would be to allow 

the Army to deploy much more rapidly than the current 

force can. Its primary disadvantage would be the costs 

associated with increased numbers of active-component 

personnel.

Costs. Implementing this option would reduce the costs 

for the Army’s investment program by $87 billion over 

the 2006-2022 period, primarily as a result of terminating the FCS program. It would add $9 billion in costs for 

the National Defense Sealift fund (a Navy account that 

would be used to purchase the additional LMSRs), yielding total savings of $79 billion for DoD’s investment program over the same period. Finally, the option would increase the Army’s O&S costs by about $45 billion 

through 2022 and by $3 billion annually thereafter (see 

Table 2-31).

Effects. With additional divisions and combat brigades, 

the Army would be more capable of fighting multiple 

wars simultaneously (see Table 2-32). It also could send 

more forces to any given conflict, thus increasing the likelihood that the Army could prosecute conflicts with a 

greater chance of success or succeed more rapidly with 

fewer casualties. Alternatively, if the Army had significant 

peacetime commitments, the additional combat forces 

might allow the Army to maintain those commitments 

during a conflict when it might otherwise be necessary to 

withdraw forces from lower-priority commitments.

The Army would also be slightly more capable of sustaining extended deployments for peacekeeping missions (see 

Table 2-33). The additional forces available in this option 

would, however, be less than sufficient to assume one 

additional commitment of about the size of Bosnia or 

Kosovo at their height or of the U.S. commitment to 

Afghanistan.

Because this alternative would increase the size of the 

active Army slightly, it would reduce the active Army’s 

Personnel 285,000 -37,000

Brigades 20 No change

1.76 -0.46

109,000 -26,000

Active Army only 1.65 +0.15

Total Army 2.75 +0.75

First brigade 14 -5

First division 20 -7

First corps 53 -23

First theater 102 -46

Current Effects of Converting to an

Force Expeditionary Army

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel
42 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-33.

Effects of Alternative 6 on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

dependence on reserve EAD units somewhat. That effect 

would be relatively limited, however, since some of the 

additional active Army personnel would also be used to 

establish new combat brigades. In addition, all National 

Guard combat forces would be fully supported under this 

option. Thus, if the Army was required to mobilize National Guard combat forces to sustain extended deployments, the National Guard would be able to mobilize and 

deploy additional support units. That action would increase the number of personnel the Army could sustain 

overseas in an extended deployment but would also 

require more reserve mobilization.

Converting to an expeditionary Army would greatly improve the speed with which the Army could deploy. The 

larger number of prepositioned equipment sets in this alternative contributes to improving the speed with which 

smaller forces (brigades and divisions) could be deployed, 

since prepositioned equipment sets would already be 

loaded on ships at the beginning of a conflict and would 

be closer to potential theaters. In this option, having 

more prepositioned equipment in larger flotillas dispersed 

near more potential theaters is the major factor in improving deployment speed for smaller units. For larger 

units, the increased number of LMSRs in the military 

fleet would allow the Army’s equipment to be transported 

in a shorter period of time. Finally, deployment speed 

would also benefit from the elimination of the corps 

structure. When current forces are deployed, the units 

associated with a corps or a theater have about as much 

equipment and personnel as an entire heavy division with 

all of its supporting units. An expeditionary force that 

would not have to deploy a corps thus would have much 

less equipment to transport and could be deployed more 

rapidly. Because each expeditionary force in this option 

would have significantly fewer support units than a current force (including the corps), deploying three expeditionary forces (with 12 combat brigades) would actually 

require somewhat less lift than a current corps (with 10 

combat brigades).

Implications for the Modular Army. Although the alternative to convert to an expeditionary Army was measured 

against the current force, converting a modular Army to 

an expeditionary Army would produce many of the same 

benefits and incur many of the same costs. The expeditionary Army would improve deployment timelines when 

compared with timelines for the current force by increasing the amount of sealift available to the force, increasing 

the number of equipment sets prepositioned on ship flotillas, and eliminating the large corps structure. Because it 

would require about the same amount of lift as the premodularity force, a modular force would benefit equally 

from the increased sealift and prepositioned equipment 

available under this alternative and would see its deployment timelines reduced by roughly equivalent amounts. 

Although the Army has not announced the details of 

what the corps structure will look like in the modular 

Army, one of its goals is to merge the corps into the 

theater, making them more flexible structures. If the 

modular Army can achieve that goal, it will produce an 

effect similar to this alternative’s restructuring of EAD 

support.

Alternative 7—Convert to a Transformational Army

This alternative illustrates the type of force that many 

defense experts, including DoD’s former Director of 

Force Transformation Arthur Cebrowski, have suggested 

would be transformational—that is, reorganized to take 

full advantage of recent advances in communications networks, precision-guided munitions, and sensors. Such 

experts typically stress the virtues of small, light ground 

formations that can be rapidly deployed and that depend 

on long-range, precision firepower instead of their own 

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

+4,000–5,000 +9,000–12,000

+0.8–0.9 +0.5–0.7

-2,000 +6,000

Maximum Sustained

Personnel Mobilized

Personnel Mobilized

Brigades

Deployment

Personnel

Brigades

Reserve-Component

Reserve-Component

Maximum Sustained

Active Army

Expeditionary Army

Premodular Army

Effects of Converting to an

Only Total Army

Deployment

Personnel
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 43

Table 2-34.

Effects of Alternative 7 on the Size and 

Composition of the Army

Source: Congressional Budget Office.

weaponry for effectiveness. This alternative would have 

fewer divisions, and the mix of divisions would be shifted 

to lighter forces and special forces groups, with each division having access to more long-range firepower, especially attack helicopters and artillery. Overall, this option 

would reduce the number of active personnel in the 

Army by 115,000 (see Table 2-34).

For this alternative, CBO designed a smaller, lighter

combat force than the current Army. Specifically, the

alternative:

B Shifts one corps from the active component to the 

reserve component;

B Eliminates four active heavy divisions;

B Restructures the remaining active Army divisions to 

have two heavy divisions, two light infantry divisions, 

and two air assault divisions;

B Creates three new active special forces groups and two 

new National Guard special forces groups;

B Eliminates two National Guard heavy divisions;

B Restructures the remaining National Guard divisions 

to have four heavy divisions and two light infantry 

divisions, all fully supported with EAD support units;

B Preserves the current National Guard separate brigades; and

B Provides twice the Army’s current level of rocket artillery and aviation assets to each division.

Those changes would make the Army much smaller, with 

a lighter mix of units than it has currently, but each unit 

would be more capable of delivering the types of longrange, precision firepower that advocates of transformation argue would make it possible for very small forces to 

defeat much larger forces without access to such technology. This option was designed so that both the active and 

reserve components would each have two corps with 

three divisions and an ACR each (in addition to the 

National Guard separate brigades). Each of those forces 

would be roughly equivalent to the Army’s contribution 

to Operation Iraqi Freedom, which successfully achieved 

the goal of destroying the Iraqi regime in a very short 

period. Proponents of transformation forces see such 

combat operations as the type that will be more likely in 

the future, with small, rapidly moving lethal U.S. forces 

easily overwhelming an opponent’s much larger conventional forces.

This alternative also would change the Army’s investment 

program. In addition to reducing the quantities of equipment that the Army would need to procure for its smaller 

forces, this alternative emphasizes numerous Army programs that would improve the Army’s ability to precisely 

deliver long-range firepower. The Army has a variety of 

such programs, including the Excalibur projectile for cannon artillery, the guided rockets for rocket artillery, and 

Longbow upgrades for the Apache helicopter.

The primary benefit of this alternative would be the

cost savings from reductions in the number of activecomponent personnel. Its primary disadvantage would be 

the reduction in the number of combat forces available to 

the Army.

Costs. Implementing this option would reduce the costs 

for the Army’s investment program by $24 billion over 

the 2006-2022 period, primarily because the Army

482,400 555,000 1,037,400

314

10 8 18

33 36 69

Supported 

brigades 33 22 55

-115,000 No change -115,000

-1 +1 No change

-4 -2 -6

-12 -2 -14

Supported 

brigades -12 +12 No change

Active Reserve

Component Component Total Army

Effects of Converting to a

Personnel

Premodular Army

Personnel

Corps

Divisions

Transformational Army

Corps

Divisions

Total Brigades

Total Brigades
44 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-35.

Effects of Alternative 7 on the

Cost of the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

Note: n.a. = not applicable.

would have fewer combat forces to modernize. It would 

reduce the Army’s O&S costs by about $166 billion over 

the same period and by about $12 billion annually thereafter (see Table 2-35).

Effects. With fewer combat brigades in this option, the 

Army would be less capable of fighting multiple wars 

simultaneously (see Table 2-36).24 It also could be less 

capable of sending additional forces to any given conflict. 

Alternatively, if the Army had significant peacetime commitments, it might have to abandon some of those commitments during a conflict because of high-priority combat needs.

Supporters of this option would argue that although it 

would decrease the overall number of combat brigades in 

the active Army, it would improve the Army’s ability to 

fight wars overall. Transformation advocates often argue 

that the size or mass of a combat force is largely irrelevant 

to its combat power but that the capability to precisely 

deliver firepower is central to success in modern conflicts. 

This alternative would give the Army fewer forces, but 

those combat forces would have access to twice as much 

long-range firepower as current forces do.25 Thus, transformation advocates would suggest that this option 

would create a force that would be at least as capable as 

today’s larger, more expensive force. CBO was not able to 

assess such claims about the qualitative improvement in 

warfighting that a brigade-based Army might provide. 

However, to illustrate the potential that such an effect 

might have, CBO assumed that the transformational 

Army could deploy a corps-sized force of six combat brigades (compared with 10 for the current force) and a theater-sized force of 12 combat brigades (compared with 20 

for the current force). If that were the case, then under 

this option, the Army would be capable of prosecuting 

more conflicts simultaneously, even though it had fewer 

combat brigades.

A transformational Army would, however, have a smaller 

pool of personnel and units to draw on for sustaining 

extended deployments (see Table 2-37). As such, it would 

be less capable of sustaining larger numbers of personnel 

or combat brigades through rotational deployments. The 

reduction in forces available under this option would be 

roughly equivalent to two or three times the size of the 

U.S. commitment to Bosnia or Kosovo or to the U.S. 

commitment to Afghanistan. It also is unlikely that transformational forces would be qualitatively superior in 

peacekeeping operations, since the additional firepower 

provided to them is unlikely to be useful in such operations—in some respects, transformational forces would 

have the opposite advantages and disadvantages as the 

dedicated peacekeeping forces of Alternative 4.

This alternative would not change the degree to which 

active forces would depend on reserve EAD units for support, so the number of reserve personnel the Army would 

need to mobilize for any given operation would not 

change appreciably. However, since the Army would be 

considerably smaller in this option, it would be unable to 

sustain extended deployments as large as the current force 

can. As a result, it would need to mobilize fewer reserve 

personnel overall to support the smaller number of active 

units that it could sustain overseas. 24. The Army would be less capable of fighting wars if it experienced 

no qualitative improvement in the ability of each brigade. Supporters of this option would argue that it would produce such an 

effect. 

Investment 129 334 605 n.a.

Operation 

and Support 398 826 1,488 99 ___ ____ ____ ___

Total 527 1,160 2,092 99

Investment -6 -14 -24 n.a.

Operation 

and Support -34 -86 -166 -12 ___ ___ ____ __

Total -40 -100 -190 -12

Transformational Army

Effects of Converting to a

Premodular Army

2010 2015 2022

Annual

Total Costs Recurring

2022

2006- 2006- 2006- Costs in

25. That large amount of additional firepower is reflected in the 

higher support ratio shown for this option in Table 2-36.
CHAPTER TWO ALTERNATIVES FOR THE ARMY’S FORCE STRUCTURE 45

Table 2-36.

Effects of Alternative 7 on the Army’s Ability to Fight Wars

Source: Congressional Budget Office.

Converting to a transformational Army would improve 

the speed with which the Army could deploy. Although at 

the level of a single brigade or division the transformational Army would need about the same amount of time 

to deploy (since each brigade would be about the same 

size as current brigades), corps- or theater-level forces 

would deploy faster, primarily because they, as defined in 

this option, would be smaller and have less equipment. 

Each deployed force in this alternative also would include 

a higher fraction of light units than the current force has, 

further hastening deployment. However, each division in 

this alternative, along with its EAD support units, actually would have somewhat more unit equipment than a 

division in the current force, and the extra weight they 

would carry would reduce the benefits from improved 

deployment speed somewhat. 

Implications for the Modular Army. Although the alternative to convert to a transformational Army was measured against the current force, converting a modular 

Army to a transformational one would produce many of 

the same benefits and incur many of the same costs. A 

smaller, lighter modular Army with access to more longrange precision firepower would have many of the same 

advantages in the sort of warfare that transformation proponents believe will characterize future conflicts. It would 

also have the same drawback regarding the forces’ ability 

to support extended deployments, since much smaller 

Army forces are simply incapable of supporting very large 

extended deployments.

The aviation structure for this alternative was designed to 

match the Army’s available number of helicopters to specific combat units. It would not change the overall number of helicopters in the Army.

Personnel 285,000 -67,000

Brigades 20 -8

1.76 +0.73

109,000 -18,000

Active Army only 1.65 +0.1

Total Army 2.75 +1.85

First brigade 14 No change

First division 20 No change

First corps 53 -24

First theater 102 -20

Current Effects of Converting to a

Force Transformational Army

Deployment Time (Days)

Reserve-Component Personnel Mobilized and Deployed

Number of Major Combat Operations Possible

Deployment for a Major Combat Operation

Ratio of Support Personnel to Combat Personnel
46 OPTIONS FOR RESTRUCTURING THE ARMY

Table 2-37.

Effects of Alternative 7 on the

Army’s Ability to Sustain Extended 

Deployments

Source: Congressional Budget Office.

Note: n.a. = not applicable.

Total Army

89,000–111,000 111,000–138,000

8.3–10.3 12.3–15.1

52,000–57,000 86,000–90,000

-28,000–36,000 -26,000–32,000

-3.0–3.8 -3.2–4.0

-24,000–26,000 -20,000–21,000

Deployment

Personnel

Maximum Sustained

Active Army

Premodular Army

Effects of Converting to a

Transformational Army

Only

Personnel Mobilized

Personnel Mobilized

Brigades

Deployment

Personnel

Brigades

Reserve-Component

Reserve-Component

Maximum Sustained
A

Detailed Descriptions of Current and

Proposed Army Units

This appendix provides detailed descriptions and diagrams of the major types of units now in the Army or 

planned under the Army’s “modularity” reorganization. It 

also describes several types of units that would be created 

under the options analyzed in this study. The descriptions 

focus on the Army’s structure in descending order of size: 

at the theater, corps, division, and brigade levels. 

Divisions and brigades come in several types—light, medium, and heavy—as well as in different generations. In 

the early 1980s, the Army reorganized its units according 

to an initiative called the Army of Excellence (AoE). 

Since then, the Army has announced two other generations of unit types, the Force XXI design and modularity, 

although it is still phasing AoE units out. (For more details about modularity, see Appendix B.) This appendix 

describes some units from all three generations, as well as 

the stabilization and reconstruction divisions discussed in 

Alternative 4 and the light and heavy Army expeditionary 

forces discussed in Alternative 6.

The diagrams in this appendix that illustrate units’ structure employ a standardized symbolic format, which is 

widely used in the Army and is based on a military standard used throughout the Department of Defense 

Figure A-1.

Symbols of Unit Size

Source: Congressional Budget Office.

APPENDIX

Platoon

Company, Battery, Troop

Battalion, Squadron

Regiment, Group

Brigade

Division

Corps

Theater

X

XX

XXX

XXXX

Armored Division

Three Artillery Battalions

One to Two Forward

Support Companies

XX

FSC
48 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-2.

Symbols of Unit Type

Source: Congressional Budget Office.

Note: Recon. = reconnaissance; MLRS = multiple-launch rocket system; HIMARS = High-Mobility Artillery Rocket System.

Light Infantry Engineers

Aviation

Maintenance

Company

Aviation

Maintenance

Troop

Armored Engineers

Stryker Engineers Air Defense

Unmanned

Aerial Vehicles

Chemical

Maintenance

Medical

Transportation

Counterbattery

Radar

Supply/

Distribution

Signals

(Communications)

Stryker Antitank

Aviation

Attack Aviation

(AH-64 Apache)

Recon. Aviation

(OH-58 Kiowa)

Utility Aviation

(UH-60 Blackhawk)

Cargo Aviation

(CH-47 Chinook)

General Support

Aviation Battalion

Aviation Support

Battalion

Division Aviation

Support Battalion

Mechanized Infantry

Stryker Infantry

Armor

Armored Cavalry

Stryker Recon.

Motorized Recon.

Light Recon.

Towed Howitzer

Self-Propelled

Howitzer

Rocket Launcher

(MLRS, HIMARS)

Light Infantry,

Heavy Weapons

GSAB

ASB

DASB

C

R

A

AMC

AMT
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 49

Figure A-3.

Structure of an Army Theater

Source: Congressional Budget Office.

Note: ASCC = Army service component command; ASG = area support group; ATS = air traffic services; CA = civil affairs; FIN = finance; 

HHC = headquarters and headquarters company; MI = military intelligence; MP = military police; ORD = ordnance; PER = personnel; PETRO = petroleum; PSYOPS = psychological operations; SHORAD = short-range air defense; TSC = theater support command. 

(Other symbols are defined in Figures A-1 and A-2.)

(DoD).1 In that format, all ground units are depicted 

with a rectangular box: a symbol inside the box indicates 

the type of unit, and a symbol above the box indicates the 

unit’s size (see Figure A-1 on page 47 and Figure A-2 on 

page 48 for a guide to those symbols). Multiple units of a 

given type and size are shown with silhouette boxes. 

Dashed boxes indicate that the number of units is 

variable.

Theaters

The Army’s theater structure is an element of the joint 

command structure for an entire theater of operations. 

The theater commander, normally a general, would also 

be the Army service component commander. The theater 

would normally be used to command and support one or 

two corps.

The largest single element of the theater structure (besides the subordinate corps) is the theater support command, which includes a number of area support groups 

to provide rear-area logistics support, a petroleum group, 

an ordnance group, a transportation command, and 

potentially a medical command (see Figure A-3). Those 

logistics commands establish and maintain the theater 

XXXX XXX

XXXX XXX

HHC TSC

MP SHORAD PETRO ASG

PSYOPS ATS PATRIOT ORD

X

X

X

X XXXX

CA

CA MI

MI MP

MP

PER

FIN

ASCC

1. Army Field Manual 101-5-1, Operational Terms and Graphics, 

contains an extensive library of those symbols and a discussion 

of their proper usage and meaning. The Congressional Budget 

Office has simplified some of the symbols, substituting Army 

abbreviations for less familiar symbols.
50 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-4.

Structure of an Army Heavy Corps

Source: Congressional Budget Office.

Note: CA = civil affairs; COSCOM = corps support command; CSG = corps support group; FIN = finance; HHC = headquarters and headquarters company; MI = military intelligence; MP = military police; PER = personnel; PSYOPS = psychological operations; SHORAD 

= short-range air defense. (Other symbols are defined in Figures A-1 and A-2.)

logistics system, which provides support to other services’ 

units (such as Marine expeditionary groups) as well as to 

the Army. The size of those elements is largely determined by the size of the forces they need to support.

The rest of the theater structure consists mainly of various support commands, brigades, and groups, with a 

variable number of subordinate battalions. The number 

of subordinate battalions in any command depends on 

the number of subordinate corps and divisions assigned 

to the theater as well as on operational factors. The support units include engineer, chemical, military police, 

military intelligence, signals, personnel, finance, civil affairs, and psychological operations units.

The remaining theater units include such fixed elements 

as the theater aviation brigade and the theater air and 

missile defense command. They provide special highlevel support functions, such as air traffic services or theater missile defense.

Corps

The corps, commanded by a lieutenant general, is the 

Army’s largest tactical formation. A corps commands and 

supports two to five divisions and an armored cavalry regiment. Slight variations exist between a heavy corps (such 

as III Corps) and a light corps (such as XVIII Airborne 

Corps), but those differences are generally minor, and all 

corps are capable of including heavy or light subordinate 

divisions. (Figure A-4 illustrates the structure of a full 

heavy corps.)

XXX XX

XX XXX XX

X

X

X

COSCOM

SHORAD

PATRIOT

CSG

HHC

PSYOPS

PER

FIN

CA

XXXXX

CA

MI MP

MI MP

A
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 51

Figure A-5.

Structure of an Army Heavy Division Under Various Designs

S

Continued

The largest single element of the corps structure (other 

than the subordinate divisions) is the corps support command, which includes a corps support group (CSG)

for the corps itself, one CSG for each subordinate division, and a medical brigade. CSGs are multifunction logistics commands with a variety of subordinate logistics 

battalions.

Most of the rest of the corps’s structure consists of combat-support brigades and groups, each with a variable 

number of subordinate battalions depending on the 

number of subordinate divisions assigned to the corps 

and on operational factors. The combat-support brigades 

include engineer, chemical, military police, military 

intelligence, signals, personnel, finance, and civil affairs 

brigades.

The corps includes the bulk of the Army’s artillery firepower, with a corps artillery commanding a variable 

number of artillery brigades. Each corps has an artillery 

brigade for the corps itself and one or two artillery brigades for each subordinate division. In addition, a corps 

contains an aviation brigade, an air-defense brigade, and 

a psychological operations battalion, which are unlikely 

to vary in size.

According to Army doctrine, separate brigades are normally attached to a corps. However, in recent rotations 

for Operation Iraqi Freedom, the Army has opted to 

attach separate brigades to divisions.

Divisions

The division, commanded by a major general, is the 

Army’s primary tactical formation. Its main elements are

~17,500 Personnel

HHC

XXXXX

XX

HHC HHC HHC

MSB

FSB

HHB HHD

DISCOM

GSAB

MI

MP

ASB

A

Army of Excellence Design
52 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-5.

Continued

Source: Congressional Budget Office.

Note: DISCOM = division support command; DSB = division support battalion; FSB = forward support battalion, HHB = headquarters and 

headquarters battery; HHC = headquarters and headquarters company; HHD = headquarters and headquarters detachment; MI = 

military intelligence; MP = military police; MSB = main support battalion. (Other symbols are defined in Figures A-1 and A-2.)

three subordinate maneuver brigades. In heavy divisions, 

the Army mixes armored units and mechanized infantry 

units in ratios of 2:1. Thus, an armored division contains 

two armored brigades and one mechanized infantry brigade, whereas the pattern is reversed for a mechanized 

infantry division. Each brigade follows the same pattern 

with its subordinate battalions (that is, an armored brigade has two armored battalions and one mechanized infantry battalion). Since the resulting mix of battalions has 

either a 5:4 or 4:5 ratio of armor to mechanized infantry, 

both armored divisions and mechanized infantry divisions are referred to generically as heavy divisions.

The three maneuver brigades in a division are organized 

for combat into brigade combat teams (BCTs) with support units from the division’s other brigades and battalions. The units that are not associated with the BCTs are 

known as the division base. The various support battalions that are not grouped under a brigade headquarters 

are called the division troops.

Two generations of heavy divisions exist in today’s Army 

(see Figure A-5). The Army of Excellence design is 

roughly 20 years old, although it has been revised slightly 

during that period. The Force XXI design dates to the 

late 1990s. A Force XXI heavy division differs from an 

AoE heavy division by having different BCTs, a different 

logistics command, and a different cavalry squadron. 

Those distinctions are relatively minor at the division 

level; they are much more apparent at the BCT level.

A

~15,500 Personnel

HHC

MI

MP

XXX X

XX

DASB

HHC HHC HHC

DSB

FSB

HHB

GSAB

DISCOM

Force XXI Design
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 53

Figure A-6.

Structure of an Army Light Division Under the Army of Excellence Design

Source: Congressional Budget Office.

Note: DISCOM = division support command; FSB = forward support battalion; HHB = headquarters and headquarters battery; HHC = 

headquarters and headquarters company; MI = military intelligence; MP = military police; MSB = main support battalion. (Other 

symbols are defined in Figures A-1 and A-2.)

In both cases, the division base includes division headquarters, a division aviation brigade, a rocket-launcher 

battalion, and some division troops. It is also reinforced 

with support units from the corps, including a CSG and 

one or two artillery brigades. But whereas the division 

base for an AoE heavy division includes a main support 

battalion and an aviation support battalion, the base for a 

Force XXI heavy division includes a division support battalion and a division aviation support battalion.

Like heavy divisions, light divisions consist of three subordinate maneuver brigades. However, those brigades are 

all of the same type (light infantry, airborne, or air assault) rather than a mix. The only major difference between types of light divisions, other than the training of 

their soldiers, is that an air assault division (of which the 

Army has only one, the 101st Air Assault Division) has 

many more aviation assets than other light divisions do.

The Army never developed a Force XXI light division but 

instead continued to evolve the AoE design (shown in 

Figure A-6). Until the Army finishes its modularity conversions, light AoE divisions will persist in the Army.

A light division’s base includes division headquarters, a 

main support battalion, an aviation maintenance company, a division aviation brigade, a battery of 155-

millimeter towed artillery, and some division troops. As 

in a heavy division, that base is reinforced with support 

units from the corps, including a combat support group 

and one or two artillery brigades.

Brigades

A brigade combat team—commanded by a colonel if the 

brigade is part of a division or by a brigadier general if it 

is separate—is the primary unit of analysis in this study. 

Just as divisions contain three subordinate maneuver brigades, BCTs contain three subordinate maneuver battalXXX X

XX

HHC

AMC

HHC HHC HHC

MSB

FSB

HHB

A

R

MI

MP

~11,500 Personnel

DISCOM
54 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-7.

Structure of an Army Heavy Brigade Under Various Designs

Continued

HHC FSB

HHC HHC HHC HHC HHB

~4,000 Personnel

MI

Army of Excellence Design

Force XXI Design

~3,500 Personnel

X

X

HHC

MI HHC HHC HHB HHC HHC

FSB

FSC FSC

BSC
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 55

Figure A-7.

Continued

Source: Congressional Budget Office.

Note: BSB = brigade support battalion; BSC = base support company; FSB = forward support battalion; FSC = forward support company; 

HHB = headquarters and headquarters battery; HHC = headquarters and headquarters company; MI = military intelligence; STB = 

special troops battalion. (Other symbols are defined in Figures A-1 and A-2.)

ions. (The number of battalions will decline to two under 

the Army’s planned modularity reorganization.) BCTs 

come in heavy, armored cavalry, medium, and light versions.

Heavy Brigade Combat Teams

As described earlier, the Army has two types of heavy 

BCTs: armored BCTs (with two armored battalions and 

one mechanized infantry battalion) and mechanized 

infantry BCTs (with two mechanized infantry battalions 

and one armored battalion). Under the Army of Excellence design, heavy BCTs are robust units relative to 

other units and Army tradition: each armored or mechanized infantry battalion contains four companies instead 

of three, and each artillery battery has eight guns rather 

than six, as in other units and past Army practice (see 

Figure A-7).

Heavy BCTs of the more recent Force XXI design follow 

the usual structure by having three companies per 

armored or mechanized infantry battalion. Thus, those 

BCTs differ from their AoE predecessors by having nine 

maneuver companies instead of 12. They also include 

more support units, such as a brigade reconnaissance 

troop and forward support companies for each maneuver 

battalion.

Under its current plans, the Army will convert all of its 

BCTs to a modular configuration by 2008. Modular 

heavy BCTs, the Army’s newest series of units, are the

Modularity Design

HHC STB BSB

HHC HHC HHC HHB HHC

FSC MI

FSC FSC

X

~3,700 Personnel
56 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-8.

Structure of an Army Armored Cavalry Regiment

Source: Congressional Budget Office.

Note: FSS = forward support squadron; HHT = headquarters troop; MI = military intelligence. (Other symbols are defined in Figures A-1 

and A-2.)

centerpiece of the modularity initiative spearheaded by 

the Chief of Staff of the Army, General Peter Schoomaker. They will differ from previous BCTs in numerous 

ways. A modular heavy BCT will contain only two 

maneuver battalions—each one comprising two armored 

and two mechanized infantry companies—rather than 

three or four battalions. Thus, it will include just eight 

maneuver companies, instead of nine or 12, and an equal 

mix of armored and mechanized infantry units, eliminating the current difference between armored BCTs and 

mechanized infantry BCTs. The new heavy brigades will 

also have a much larger set of support units, including 

some types of units (such as unmanned aerial vehicles and 

counterbattery radars) that were previously found only in 

divisions. In addition, the modular BCTs will have a 

reconnaissance squadron that is larger and more robust 

than the brigade reconnaissance troop in a Force XXI 

heavy BCT. Modular BCTs are also designed to separate 

easily into battalion-sized combat teams, should that 

prove necessary, thereby increasing the Army’s flexibility.

Armored Cavalry Regiments

An ACR, which is commanded by a brigadier general, 

contains three subordinate armored cavalry squadrons 

(see Figure A-8). Unlike other Army cavalry units, those 

squadrons are large, robust, include armor and artillery, 

and are intended to be capable of engaging enemy forces 

directly. Thus, CBO considers ACR squadrons to be 

maneuver units (unlike other cavalry squadrons).

Armored cavalry regiments are designed to be deployed 

with a corps to scout ahead of the corps or secure its 

flanks. For that reason, they are relatively large, selfcontained, and powerful compared with other Army

~4,800 Personnel

HHT

MI

FSS

HHT HHT HHT

AMT AMT

R

A
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 57

Figure A-9.

Structure of an Army Medium (Stryker) Brigade

Source: Congressional Budget Office.

Note: BSB = brigade support battalion; HHB = headquarters and headquarters battery; HHC = headquarters and headquarters company;

MI = military intelligence. (Other symbols are defined in Figures A-1 and A-2.)

BCTs. They also require more personnel than any other 

kind of BCT. In addition, they are the only type of BCT 

to include an aviation troop. That troop can have more 

than half as many helicopters as a division does, giving 

ACRs access to much more firepower than most BCTs 

have.

Today’s ACRs are all structured according to the Army of 

Excellence design. Under the Army’s plan for modularity, 

those ACRs may be converted to heavy BCTs.

Medium Brigade Combat Teams

The Army currently has two brigade combat teams, 

called Stryker BCTs (SBCTs), that are considered medium brigades (see Figure A-9). SBCTs are intended to 

provide the Army with a force that is lighter and easier to 

deploy than heavy BCTs but has more combat capability 

than light BCTs. The main elements of an SBCT are 

three subordinate infantry battalions, equipped with 

Stryker vehicles. Those battalions include the Mobile 

Gun System Stryker variant for increased firepower.

By design, SBCTs have extremely limited logistics capabilities. The Army has a dedicated type of corps-level support battalion, referred to as the “corps plug,” for each 

SBCT (that battalion is not included in Figure A-9). 

Employing an SBCT would almost always require deploying at least the corps plug in addition to the SBCT.

The Army is in the process of converting four more brigades to the SBCT structure. All SBCTs are considered 

Force XXI units, and the Army’s current plan for modularity does not call for changing their structure. Most of 

the new SBCTs will be divisional brigades, despite the 

fact that there are no medium or Stryker divisions.

Light Brigade Combat Teams

As explained above, the main elements of a BCT are its 

subordinate maneuver battalions. In light BCTs of the

~3,900 Personnel

HHC

HHC HHC HHC HHB

BSB

X

MI
58 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-10.

Structure of an Army Light Brigade Under Various Designs

Source: Congressional Budget Office.

Note: BSB = brigade support battalion; FSB = forward support battalion; FSC = forward support company; HHB = headquarters and headquarters battery; HHC = headquarters and headquarters company; MI = military intelligence; STB = special troops battalion. (Other 

symbols are defined in Figures A-1 and A-2.)

~2,500 Personnel

~3,200 Personnel

X

X

Army of Excellence Design

Modularity Design

HHC

MI HHB HHC HHC

FSB

HHC STB BSB

HHC HHC HHB HHC HHC

FSC

FSC

FSC

MI
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 59

Figure A-11.

Structure of a Notional Stabilization and Reconstruction Division

Source: Congressional Budget Office.

Note: BSB = brigade support battalion; CA = civil affairs; DISCOM = division support command; EOD = explosive-ordnance disposal;

FSB = forward support battalion, HHC = headquarters and headquarters company; MI = military intelligence; MP = military police;

PSYOPS = psychological operations; S&R = stabilization and reconstruction; TRAINER = training assistance. (Other symbols are 

defined in Figures A-1 and A-2.)

Army of Excellence design, those battalions consist of 

three light infantry, airborne, or air assault battalions (see 

Figure A-10). An AoE light BCT has extremely limited 

logistics capabilities and contains less firepower than any 

other kind of BCT; however, it includes more infantry 

personnel than other BCTs do.

The Army is converting its AoE light BCTs into modular 

light BCTs, a process it plans to finish in 2007. (The 

Army never developed Force XXI light brigades.) Modular light BCTs have two subordinate maneuver battalions 

rather than three, each with three subordinate light infantry companies and a heavy-weapons company armed with 

antitank missiles, mortars, and machine guns. As with 

other light forces, under the modularity plan, there will 

be no difference among light infantry, airborne, and air 

assault light BCTs except for the training their personnel 

receive.

Although modular light BCTs have fewer maneuver companies than their AoE predecessors do (eight instead of 

nine), they have a much larger set of support units—including some types, such as unmanned aerial vehicles and 

counterbattery radars, that were previously found only in 

divisions. They also, unlike their predecessors, include a 

reconnaissance squadron. Modular light BCTs have the 

added flexibility of being easy to separate into battalionsized combat teams.

XX

~18,000 Personnel

X XX

HHC

MI

TRAINER

HHC MP

PSYOPS

BSB

CA EOD

FSB

S&R DISCOM

S&R
60 OPTIONS FOR RESTRUCTURING THE ARMY

Figure A-12.

Structure of Notional Heavy and Light Army Expeditionary Forces

Continued

New Units from the Options 

in This Analysis

Some of the alternative reorganization plans discussed in 

Chapter 2 envision creating new types of Army units. 

The rest of this appendix describes several of those units.

Stabilization and Reconstruction Divisions

Under Alternative 4, the Army would establish five socalled stabilization and reconstruction (S&R) divisions—

along the lines of a proposal made in a study by the 

National Defense University—that would be intended 

for peacekeeping tasks. The major elements of an S&R 

division would consist of a Stryker BCT (to provide combat power), four S&R brigades, and a support command 

(see Figure A-11 on page 59). The Stryker BCT would 

have the same structure as those now in the Army. The 

S&R groups would comprise military police, medical, 

civil affairs, engineer, and psychological operations battalions. The support command would include an area support battalion for each S&R group. The division base for 

an S&R division would feature an explosive-ordnancedisposal battalion and a training-assistance battalion as 

well as more-common support elements.

Heavy and Light Army Expeditionary Forces

Alternative 6 would reorganize the Army into a series of 

expeditionary forces (similar to Marine expeditionary 

forces). Each force, heavy or light, is intended to be selfcontained and rapidly deployable (see Figure A-12). 

A heavy expeditionary force would contain a ground 

combat element (with two armored BCTs and two mechanized infantry BCTs), an air combat element (with six 

squadrons of helicopters and Patriot missile air-defense 

units), and a support group (with support elements like 

those included in a division support command and corps

XX

~43,000 Personnel

XXXXX

HHC

MI

MP

DISCOM

PATRIOT HHC

DSB

DASB

CSG

X

A

R

C FSB FSB

Heavy Army Expeditionary Force
APPENDIX A DETAILED DESCRIPTIONS OF CURRENT AND PROPOSED ARMY UNITS 61

Figure A-12.

Continued

Source: Congressional Budget Office.

Note: BSB = brigade support battalion; CSG = corps support group; DISCOM = division support command; DSB = division support battalion; FSB = forward support battalion; HHC = headquarters and headquarters company; MI = military intelligence; MP = military 

police. (Other symbols are defined in Figures A-1 and A-2.)

support group). It would also include numerous types of 

echelons-above-division (EAD) support units that are 

now maintained at the corps level, such as additional 

rocket-launcher artillery battalions, engineer battalions, 

and other types of support units. (Some of those other 

EAD units are not shown in Figure A-12 because of their 

large number and small size.)

A light expeditionary force, by comparison, would also 

contain a ground combat element (but with three light 

BCTs and one Stryker BCT), an air combat element 

(with 11 squadrons of helicopters as well as Patriot missile air-defense units), and a support group (with support 

elements like those included in a division support command and corps support group). Like its heavy counterpart, a light expeditionary force would also include numerous EAD support units currently maintained at the 

corps level, such as additional rocket-launcher artillery 

battalions, engineer battalions, and other types of support 

units (some of which are not included in Figure A-12).

The command levels and arrangements displayed in 

Figure A-12 are notional. The Army might prefer that 

such expeditionary forces be equivalent to a corps-level 

command—with division-level ground, air, and support 

commanders—or some other arrangement. Those 

changes would not materially affect the size or composition of such a formation, and the Congressional Budget 

Office is not able to evaluate what types of command 

arrangements would be superior to others.

XX

~39,000 Personnel

Light Army Expeditionary Force

XXXXX

HHC

MI

MP

DISCOM

HHC HHC HHC

DSB

DASB

CSG

FSB BSB

X

R

C

PATRIOT

A

B

The Army’s Plan for Modularity

As described in Chapter 1, the Army is currently 

undertaking a large-scale reorganization, known as modularity. The Congressional Budget Office (CBO) does 

not have enough information about that reorganization 

plan to analyze it in the same manner that CBO analyzed 

the Army’s previous force structure or the various alternatives examined in Chapter 2. Parts of the plan that deal 

with combat forces have been announced; parts that deal 

with support forces have either not yet been decided or 

not made public. This appendix describes the modularity 

plan as CBO understands it and outlines the limited conclusions that CBO has been able to draw about the implications of modularity.

For the purposes of CBO’s analysis, the core elements of a 

force structure are the number and types of major combat 

units, including the number of echelons-above-division 

(EAD) support units required by those combat units; the 

distribution of combat and support units between the 

active and reserve components; and the size of the forces 

and weight of the equipment that would be deployed to 

a contingency. Having descriptions of those elements 

allowed CBO to quantitatively evaluate the measures of 

warfighting, peacekeeping, dependence on the reserves, 

and deployment speed that are used in this study. Because 

CBO did not have access to a full set of those descriptive 

elements for the modular Army, it could not evaluate the 

modular Army in terms of those measures. This appendix 

describes some reasonable assumptions that could be 

made to fill in the gaps in CBO’s understanding of modularity and estimates how well the modular force might 

perform, according to those measures, if the assumptions 

proved true.

Overview of Modularity

CBO has four primary sources of information about the 

Army’s modularity plan. The first is a series of briefings 

and press reports that the Army has provided to the public and the Congress. Army briefings generally address 

high-level topics and lack extensive details, but they do 

establish the service’s broad goals and policy initiatives. 

The second source of information is an Army database, 

WebTAADS, which is used to manage units at a high 

level of detail.1 WebTAADS provides information only 

about changes in the Army’s structure that have been formally decided—and thus is of limited use for describing 

future changes—although it does offer a large amount of 

detail about unit changes that have been approved. The 

third source is a database of Table of Organization and 

Equipment (TOE) documents (the templates that describe unit designs) maintained by the Army Force Management Support Agency’s Requirements Division.2

 TOE 

documents can be used for a variety of purposes, but 

CBO primarily used them to determine how much 

equipment various types of units would have and thereby 

estimate how much a unit’s equipment would weigh and 

how easily the unit could be transported and deployed. 

The last source of information about modularity is a large 

Army paper called Army Comprehensive Guide to Modularity.

3 The guide currently consists of a volume that describes major combat units and command relationships. 

The second volume, describing higher-echelon units and 

support units, has not yet been published.

APPENDIX

1. WebTAADS is an Internet version of The Army Authorization 

Document System (TAADS), which the Army uses to manage its 

units. That system is extremely detailed since it is used to establish 

authorized levels of personnel and equipment for tens of thousands of units, subunits, and other elements of the Army.

2. Those templates differ slightly from actual units; in essence, they 

describe how any type of unit “should” be structured. For a variety 

of reasons, actual units tend to deviate from the exact TOE pattern in terms of number of personnel, equipment, subordinate 

units, and so forth. However, most units are similar enough to the 

TOE pattern that TOE documents are useful for analyzing them.

3. U.S. Army Training and Doctrine Command, Army Comprehensive Guide to Modularity, version 1.0 (October 8, 2004).
64 OPTIONS FOR RESTRUCTURING THE ARMY

The overriding goal of the modularity reorganization is to 

convert the Army’s combat brigades into a series of units 

with new designs that, according to Army briefings, will 

be more capable of independent operations. In addition, 

the number of combat brigades in the active Army will 

rise from 33 at the beginning of 2004 to either 43 or 48 

by the end of the decade. (The Army will not decide the 

exact number for several years.) 

That overall plan includes the following specific changes:

B Creating a new type of heavy brigade and new type of 

light brigade, each with two maneuver battalions, a 

reconnaissance battalion, and other units.4 (Those 

new brigades are illustrated in Appendix A.) 

B Converting all combat units other than Stryker brigades and scout groups to the new heavy or light brigade configuration. (Stryker brigades and the Army’s 

one scout group, which is in the National Guard, 

would keep their current configurations.) 

B Organizing all combat brigades (both divisional and 

separate) into permanent brigade combat teams rather 

than the current practice of task-organizing divisional 

brigades into brigade combat teams on an ad hoc basis 

as specific tasks require.

B Creating new active combat brigades by increasing the 

number of combat brigades in active divisions to four 

(exclusive of any Stryker brigades). If the Army grows 

to 48 combat brigades, it will have 10 active divisions—each with four combat brigades as well as five 

Stryker brigades, a separate heavy brigade (or an 

armored cavalry regiment), and two separate airborne 

brigades.5 If the Army grows only to 43 combat brigades, the 1st Infantry Division and 1st Armored Division will have three brigades apiece, the 2nd Infantry 

Division will have two brigades (exclusive of any 

Stryker brigades), and the Army will have just one 

separate airborne brigade.

B Reducing the number of combat brigades in the Army 

National Guard and consolidating all of the existing 

separate brigades within National Guard divisions. 

The National Guard will have eight divisions, each 

with four combat brigades, as well as a separate 

Stryker brigade and separate scout group. Over time, 

heavy National Guard brigades will be converted to 

light brigades.

B Redefining the current brigade level of command as 

the “Unit of Action.” That level will continue to be 

identified with current brigade headquarters, flags, 

and insignia and can be referred to as the brigade level 

(see Figure B-1).

B Merging the command responsibilities of the current 

division level and some of the command responsibilities of the current corps level into a “Unit of Employment (X),” or UE(X), level of command. That level 

will be identified with current division headquarters, 

flags, and insignia and can be referred to as the division level.

B Converting current corps headquarters into a “ThreeStar UE(X)” to be used for command and control in 

larger theaters. That level will be identified with current corps headquarters, flags, and insignia and can be 

referred to as the corps level.

B Merging the command responsibilities of the current 

theater level and some of the command responsibilities of the current corps level into a “Unit of Employment (Y),” or UE(Y), level of command. That level 

will be identified with current “named Army” headquarters (such as U.S. Army Europe or U.S. Army 

Pacific, but not the 7th Army or 8th Army), flags, and 

insignia and can be referred to as the theater level.

B Converting divisions into a flexible headquarters element with a set of combat brigades and support brigades. The support brigades will generally be the same 

as those found in current divisions (in some cases with 

new names, such as a “fires brigade” instead of a “divi4. Several sources, such as Department of the Army, 2004 Army 

Transformation Roadmap (July 2004) and some Army briefings, 

indicate that the Army may seek to add a third combat battalion 

to each of those brigades, if feasible. Most other Army sources, 

including the Army Comprehensive Guide to Modularity and WebTAADS, do not indicate such plans.

5. Those last items are somewhat unclear. The Army is apparently 

still debating whether to convert the 3rd Armored Cavalry Regiment to a standard heavy brigade configuration, although the general statement about modularity is that there will be only three 

types of combat units: heavy, light, and Stryker. Most Army briefing charts show a new airborne brigade being created in 2007, but 

at least one chart shows an infantry brigade. Those units would be 

structured the same but trained slightly differently.
APPENDIX B THE ARMY’S PLAN FOR MODULARITY 65

Figure B-1.

Army Command Levels Before and 

After Modularity

Source: Congressional Budget Office.

sion artillery”), with the exception of an as-yetundefined “maneuver enhancement” brigade.

B Converting all corps- and theater-level support units 

into a standardized set of support brigades that can be 

allocated more flexibly. The UE(Y) will include some 

of the traditional theater-level organizations (such as 

the theater support command, medical command, 

and aviation brigade) as well as some new organizations (such as the theater network command).

B Establishing a trainees, transients, holdees, and students (TTHS) account for both the Army Reserve and 

Army National Guard.

B Collecting Army Reserve support units into 10 to 12 

“Army Reserve expeditionary packages” similar to the 

concept of air expeditionary forces used by the Air 

Force.

B Temporarily increasing the size of the active Army by 

30,000 personnel. Those personnel would be available 

through at least 2007 and would be used to create the 

additional active combat brigades. After 2007, the 

Army intends to identify enough nondeployable 

(Table of Distribution and Allowances, or TDA) units 

and TTHS positions that could be eliminated to 

return to its permanent end-strength level by 2011. 

That would be achieved by getting rid of some overhead positions, hiring civilians to perform certain 

administrative functions that are now performed by 

soldiers, and reducing the frequency with which soldiers are assigned to new units. (The permanent endstrength level is assumed to be 482,400, until the 

impact of the 2005 defense authorization act, which 

increased the Army’s size, is incorporated into the 

Army’s plans.) 

B Assigning two National Guard divisions to the mission of strategic reserve and the other six to homeland 

security or peacekeeping missions.

To perform a detailed analysis of that plan, CBO would 

need information about various elements that either have 

not been decided or have not been announced. That 

information includes answers to such questions as, What 

types and designs of support brigades, and how many of 

each type, will this force require? Will support forces continue to be organized according to a doctrine-based set of 

rules that includes fixed ratios of support units to combat 

units? Will support forces still be organized so that 

higher-level headquarters have fixed elements that must 

be deployed for any large operation? How will the 

theater-level commands be organized, and how large will 

they be? Will the Three-Star UE(X) include any distinct 

support elements? Will all existing types and levels of 

support be maintained? What level of support units will 

be required for National Guard divisions? Will the Army 

find 30,000 TDA and TTHS positions to cut in order to 

return to its normal end strength? And can the Army 

expand to 48 active combat brigades without additional 

personnel beyond the 30,000 required to attain a size of 

43 active combat brigades?

Assumptions About the Impact of 

Modularity on the Army’s Force

Structure

Because the Army’s modularity plan includes an indeterminate number of combat brigades (either 43 or 48 in 

the active component and 34 in the National Guard) and 

does not fully describe the EAD support requirements 

that those combat brigades will entail, it is unclear exactly 

how many personnel the Army will require for modularity. Other factors also make it difficult to estimate the final size of the Army under the modularity plan, such as 

the question of whether the Army will be able to identify 

30,000 TDA/TTHS positions for elimination and the 

possible effects of Congressional action to change the size 

of the active component.

Brigade Unit of Action

Division Unit of Employment (X)

Corps “Three-Star” Unit of

 Employment (X)

Theater Unit of Employment (Y)
66 OPTIONS FOR RESTRUCTURING THE ARMY

Table B-1.

Potential Size of the Modular Army

Source: Congressional Budget Office.

Notes: “Reserve” refers to the reserve component (the Army National Guard and Army Reserve).

UA = Unit of Action; ACR = armored cavalry regiment; n.a. = not applicable; UE(X) = Unit of Employment (X).

a. These numbers assume that the Army retains the 3rd Armored Cavalry Regiment in its current form.

CBO has estimated a range of potential outcomes for the 

modular Army on the basis of various assumptions about 

force structure described below. The resulting estimates 

of the potential size of the Army and of the possible distribution of forces between the active and reserve components underlie CBO’s attempt to evaluate how well the 

modular Army might perform according to the measures 

of capability used in this study.

Combat Forces

The first element of the Army’s plan is a new combat brigade structure. In addition, according to the WebTAADS 

database, the Army is planning new structures for the 3rd 

Infantry, 4th Infantry, 10th Light Infantry, and 101st Air 

Assault Divisions. CBO used that information to estimate the total size of the Army’s combat forces under the 

modularity plan (see Table B-1).

CBO’s estimate assumes that modular divisions will either be heavy or light. A heavy division will resemble the 

pattern of the modular 3rd and 4th Infantry Divisions as 

detailed in WebTAADS, and a light division will resemble the pattern of the modular 10th Light Infantry and 

101st Air Assault Divisions. The 101st Air Assault Division will have two aviation brigades (as is the case for the 

current force), and all other light divisions will have a single aviation brigade. The six heavy divisions and four 

light divisions in the active component will all retain their 

current status, and the National Guard will have six heavy 

and two light divisions.6

 All heavy divisions will have a 

heavy UE(X) headquarters, support command, artillery 

brigade, and aviation brigade. All light divisions will in3,675 19 18 69,825 66,150 21 18 77,175 66,150

3,250 18 14 58,500 45,500 21 14 68,250 45,500

3,875 5 1 19,375 3,875 5 1 19,375 3,875

4,750 1 0 4,750 0 1 0 4,750 0

1,800 0 1 0 1,800 0 1 0 1,800 __ __ ______ ______ __ __ ______ ______

Subtotal n.a. 43 34 152,450 117,325 48 34 169,550 117,325

1,050 6 6 6,300 6,300 6 6 6,300 6,300

550 6 6 3,300 3,300 6 6 3,300 3,300

2,175 6 6 13,050 13,050 6 6 13,050 13,050

425 6 6 2,550 2,550 6 6 2,550 2,550

975 4 2 3,900 1,950 4 2 3,900 1,950

2,650 5 2 13,250 5,300 5 2 13,250 5,300

475 4 2 1,900 950 4 2 1,900 950 ___ ___ _____ _____ ___ ___ _____ _____

n.a. n.a. n.a. 44,250 33,400 n.a. n.a. 44,250 33,400

Total n.a. 43 34 196,700 150,725 48 34 213,800 150,725

Reserve Active

43-Brigade Force 48-Brigade Force

Personnel Number of Units Number of Personnel Number of Units Number of Personnel

Reserve

Brigades

Heavy UA

Light UA

per Unit Active Reserve Active Reserve Active

Stryker

ACRa

Scout

Division Support

Heavy UE(X)

Heavy artillery

Heavy aviation

Heavy support

Light UE(X)

Light aviation

Light support

Subtotal 

6. Most current National Guard divisions have a mixed type of division base and mixed light and heavy subordinate combat brigades—a setup that makes it difficult to meaningfully categorize 

National Guard divisions. If CBO’s assumption about the mix of 

light and heavy National Guard division bases is incorrect, the 

National Guard’s personnel requirement will decline by about 100 

for every additional division base that is light instead of heavy.
APPENDIX B THE ARMY’S PLAN FOR MODULARITY 67

clude a light UE(X) headquarters, support command, 

and aviation brigade. CBO’s estimate is based on the mix 

of combat brigades that is now planned for 2007, when 

active modularity conversions will be complete and the 

decision about whether to have 43 or 48 brigades will 

have been made. 

Currently, the Army has about 170,000 active personnel 

and a similar number of National Guard personnel in 

major combat units. If CBO’s assumptions are correct, 

the modularity plan will imply a different pattern of personnel distribution. The active component will need 

about 25,000 to 45,000 additional positions for major 

combat units, whereas the National Guard will need 

20,000 fewer such positions. Since the 43-brigade force 

requires 25,000 additional active personnel, the Army 

will probably be able to achieve that force using the temporary increase of 30,000 in its size. The 48-brigade 

force, however, requires more than 45,000 additional 

active personnel, which means that the Army will need to 

make other changes to free up personnel positions for 

major combat units if it wants a force of that size. In both 

cases, the share of the Army’s combat personnel that are 

in the active component will increase.

Echelons-Above-Division Support Forces

The second major element of any force structure is the 

size and type of EAD support forces that the major combat units will require. CBO does not have quantitative 

details about the modular Army’s requirements for EAD 

support. For the purposes of this analysis, it may be plausible to assume that major combat units in the modular 

Army will need roughly the same levels of support forces 

that current units do.7

The Army’s current force requires about 170,000 personnel to fill out the support positions associated with its two 

theaters and four corps. Another 20,000 personnel are 

associated with special forces units that do not vary with 

the number of combat forces in the Army. The rest of the 

Army’s approximately 430,000 EAD positions are associated with units that provide more-direct support to major 

combat units (and are required under the Army’s current 

set of doctrinal rules). Those 240,000 personnel, however, are significantly less than the Army would need if all 

of the National Guard divisions were fully supported. 

Combat divisions require about one soldier in an EAD 

support unit for each soldier in the division itself.8

 CBO 

estimates that the Army lacks about 75,000 personnel 

positions that would be required to fully support all of 

the National Guard combat divisions.

If the modular Army retains some type of higher-echelon 

formation that provides support similar to that of the 

current corps and theater levels, and if its modular divisions and brigades continue to require the present ratio of 

EAD support personnel to major combat personnel, the 

Army can expect to need another 5,000 to 25,000 personnel in EAD support units for the modular force (in 

other words, the 25,000 to 45,000 additional active combat personnel minus the 20,000 fewer National Guard 

combat personnel). That addition would not change the 

presumed 75,000-person gap between the current number of Army support units for National Guard divisions 

and the number required to fully support those divisions.

Because the modular Army will have more active personnel and fewer reserve personnel in major combat units 

and will require more EAD units to support those active 

combat units (and fewer EAD units to support National 

Guard combat units), it is reasonable to assume that the 

Army will transfer EAD support units from the active 

component to the reserve component as part of modularity. That shift would reduce the requirement for active 

personnel by taking advantage of the reduced requirement for reserve personnel. It would also make active 

combat units far more dependent on reserve EAD support units. Currently, the active Army contains about 40 

percent of the EAD support units it requires, CBO estimates. If the Army grows to 48 active combat brigades, 

CBO’s assumptions about EAD support requirements 

are correct, and the active Army does not permanently 

increase in size, that fraction will decline to about 30 

percent.

The Army’s overall requirement for personnel in EAD 

support units could change if the Army altered the levels 

of support provided to National Guard combat forces. As 

noted above, the Army has suggested that two National 

7. In this discussion, the current force refers to the Army’s structure 

prior to modularity.

8. Separate brigades, however, require far fewer EAD support personnel, according to the Army’s rules. That is not because separate 

brigades are expected to fight without support. It is because the 

rules assume that a separate brigade will be assigned to a corps or 

division that will use its support units to support the separate brigade. About 65,000 of the National Guard’s combat personnel are 

in separate brigades.
68 OPTIONS FOR RESTRUCTURING THE ARMY

Guard divisions will be designated as a strategic reserve 

under the modularity plan and that six National Guard 

divisions will be designated for performing peacekeeping 

missions and homeland security duties. If the divisions 

allocated to the strategic reserve received a full set of EAD 

support units but the others were not supported, the 

requirement for EAD support units would be similar to 

that under the Army’s current structure. 

At the same time, however, Army briefings from January 

and February 2004 indicate that the Army planned to 

increase the number of National Guard separate brigades 

maintained at higher levels of manning and readiness. 

Although more-recent Army sources do not discuss the 

issue, the earlier briefings may indicate that the Army is 

planning to increase the level of support provided to 

National Guard combat formations.

Administrative Units and Individuals

Under the modularity plan, the Army intends to offset 

the increase in its requirement for personnel in TOE 

units by reducing the number of personnel in TDA or 

TTHS positions. One factor complicating that intention 

is that the Army has begun implementing plans to create 

small TTHS accounts in both the Army Reserve and the 

Army National Guard. CBO assumes that those accounts 

will require about 10,000 additional positions in the 

reserve component.9

If CBO’s assumptions about the size of the Army’s major 

combat units and the Army’s requirement for EAD support forces are correct, the Army will need an additional 

10,000 to 50,000 personnel positions for TOE units. 

With those numbers added to the Army’s requirement for 

10,000 additional positions to establish TTHS accounts 

in the reserves, the Army will need to eliminate 20,000 to 

60,000 positions—either from active TDA/TTHS positions or from reserve TDA positions. The Army has 

announced a strategy for reducing end strength that relies 

on eliminating 30,000 active TDA/TTHS positions, as 

well as achieving other efficiencies. If it meets that goal, it 

should be able to have a 43-brigade force without a permanent increase in size.

If the Army cannot manage to cut at least 20,000 active 

TDA/TTHS positions, or if it wants a 48-brigade force, 

it will need more personnel (assuming that CBO’s assumptions are correct). The 48-brigade Army would 

require 40,000 more positions than the 43-brigade Army, 

which means that the service could potentially require 

another 60,000 personnel.

The Army might be able to offset that requirement by 

reducing the level of support it provides to National 

Guard combat units. Alternatively, it could request that 

the temporary 30,000-person increase in size be made 

permanent. Finally, it is possible that the modular Army 

might not need higher-echelon formations similar to the 

corps or theater, which would greatly reduce its total 

requirement for EAD support units.

Overall Force Structure

On the basis of its assumptions and the considerations 

discussed above, CBO estimates that the Army’s modularity plan could require up to 60,000 additional personnel—depending on whether the Army opts for a 43-

brigade or 48-brigade force and whether it makes its 

desired TDA/TTHS reductions. A 43-brigade force 

could be achieved with no extra personnel, but it is 

unlikely that a 48-brigade force could be achieved with 

less than 30,000 additional personnel. If the Army executes its modularity plan without a rise in the number of 

active personnel, that plan will increase the active Army’s 

dependence on the reserve component for support units.

Implications for Warfighting

Modularity will affect the Army’s warfighting ability by 

changing the number and size of the service’s combat brigades. However, because modular brigades will be significantly different from premodular forces, simply comparing the number of combat brigades in the premodular 

and modular Army is misleading.

Directly measuring the combat capability of units is difficult, and the most sophisticated attempts to do so use extensive computer models that CBO does not have access 

to. But modular units will be manned with the same 

types of soldiers as current units and will employ the 

same types of equipment that the Army uses now. Thus, 

9. CBO made that assumption because it is unclear from Army 

sources how many positions the service intends to create. At least 

one Army briefing suggests that the service may try to create an 

account as large as 80,000. However, because adding a TTHS 

position requires either increasing the size of the reserve component or eliminating a personnel position in a unit, such a large 

account seems unlikely. CBO’s figure of 10,000 is a fairly conservative estimate. If the Army created a larger TTHS account than 

CBO assumes, it would require a greater number of additional 

personnel.
APPENDIX B THE ARMY’S PLAN FOR MODULARITY 69

the easiest way to compare different brigades is to assume 

that either the number of personnel or the number of 

some type of subordinate unit (such as a battalion or 

company) can be used to normalize the differing sizes of 

the different brigade types.

Most modular brigades (other than the Stryker brigades 

and perhaps the 3rd Armored Cavalry Regiment) will 

have two subordinate maneuver battalions, as opposed to 

three in most current brigades. However, those modular 

battalions will generally contain four subordinate maneuver companies, in contrast with the three companies in 

most current battalions. CBO chose to normalize modular and current brigades using the company, whose definition does not appear to have changed under the modularity plan, as opposed to the battalion, which has been 

redefined.10

In fully normalized terms, the Army’s current force structure contains about 624 maneuver companies. The 43-

brigade modular Army would have 618 maneuver companies, whereas the 48-brigade modular Army would 

have about 658 maneuver companies (see Table B-2). By 

that measure, the 43-brigade modular Army would have 

slightly less combat power than the current force, but the 

48-brigade Army would have about 5 percent more combat power than the current force (equivalent to slightly 

more than three current combat brigades). Comparing 

the number of personnel required for combat units in the 

modular Army yields a similar result: the 43-brigade force 

would have essentially the same amount of combat power 

as the current force, whereas the 48-brigade Army would 

have over 7 percent more combat power than today’s 

force.

In both the 43- and 48-brigade modular forces, a higher 

percentage of the Army’s combat units would be in the 

active component than is the case today. Thus, the Army 

would clearly have more active combat forces. Because 

the Army has not employed National Guard combat 

units in major combat operations since the Korean War, a 

larger number of active combat units might mean a larger 

number of combat units that could effectually be used in 

major combat operations.11

Those comparisons omit the effect that support forces 

have on a unit’s combat power. Although maneuver units 

are the core of the Army’s forces, their ability to fight 

effectively depends on extensive amounts of support. Two 

identical maneuver units with differing levels of support 

can have very different capabilities in combat. Almost all 

types of support units contribute in relatively obvious 

ways to improved combat capability—for example, additional artillery units provide extra firepower, military 

intelligence units can identify new targets or objectives, 

additional logistics units allow combat units to sustain a 

higher pace of operations without running out of fuel or 

ammunition, and so forth. It is possible that the modularity plan will either improve or degrade the level of support that Army units receive (and thus their combat capability relative to this comparison). However, as noted 

above, CBO does not know what level of EAD support 

the Army intends to give modular forces.

A final factor in comparing combat capability is that 

some proponents of modularity argue that modular brigades would be qualitatively superior to current brigades—despite having fewer combat companies—because of their design, structure, or equipment. CBO is 

unable to evaluate such claims. If they are true, the modularity plan may increase combat power to a greater ex10. That comparison is based on maneuver units. There does not 

appear to be a strict definition of such units, but they are generally 

accepted to be front-line combat units capable of closing with the 

enemy by means of fire and maneuver. CBO assumed—on the 

basis of units’ composition and missions—that armored and 

infantry companies count as maneuver forces, as do armored cavalry troops from armored cavalry regiments. It is possible to argue 

that other types of units (such as attack-helicopter units, other 

reconnaissance troops, and so on) should also be considered 

maneuver units. Including those units would alter the results of 

this comparison.

Some analysts have argued that other reconnaissance troops in the 

modular force should also be considered maneuver units because 

of the growing importance of intelligence and reconnaissance 

capabilities in conducting modern warfare. However, such units 

differ in various ways—including their small size, limited weaponry, and narrow range of missions—from more-traditional considerations of what constitutes a “combat” unit. 

If all reconnaissance companies were considered maneuver units, 

the 43-brigade force would have about 19 percent more combat 

units than the premodular force, and the 48-brigade force would 

contain about 27 percent more combat units than the premodular 

force.

11. The Army deployed the National Guard’s 42nd Infantry Division 

to Iraq in the 2005 rotation of forces. However, that deployment 

included only the division base, not the division’s brigade combat 

teams.
70 OPTIONS FOR RESTRUCTURING THE ARMY

Table B-2.

Number and Types of Brigades in Premodular and Modular Forces

Source: Congressional Budget Office.

Notes: “Reserve” refers to the reserve component (the Army National Guard and Army Reserve).

BCT = brigade combat team; ACR = armored cavalry regiment; n.a. = not applicable; UA = Unit of Action.

a. This number is three companies fewer than the number of brigades multiplied by the number of companies per brigade because one of 

the Army’s airborne brigades, the 173rd, currently has only two battalions.

b. Assumes that the Army retains the 3rd Armored Cavalry Regiment in its current form.

c. CBO did not count the National Guard scout group as a maneuver brigade for the purposes of this analysis. That formation is shown here 

only to simplify comparisons with the Army’s public statements.

d. This scout group is not counted in the total since CBO did not include it as part of the 36-brigade force discussed in this analysis.

3 9 3,500 16 21 144 189

3 9 2,600 13 14 114 a 126

3 9 3,875 3 0 27 0

3 12 4,750 1 b 1 12 12

0 0 1,800 0 1 d 0 0 __ __ ___ ___

Total n.a. n.a. n.a. 33 36 297 327

2 8 3,675 19 18 152 144

2 8 3,250 18 14 144 112

3 9 3,875 5 1 45 9

3 12 4,750 1 0 12 0

0 0 1,800 0 1 0 0 __ __ ___ ___

Total n.a. n.a. n.a. 43 34 353 265

2 8 3,675 21 18 168 144

2 8 3,250 21 14 168 112

3 9 3,875 5 1 45 9

3 12 4,750 1 0 12 0

0 0 1,800 0 1 0 0 __ __ ___ ___

Total n.a. n.a. n.a. 48 34 393 265

Battalions Companies Personnel Active Reserve Active

Scout

Heavy UA

Light UA

Light UA

48-Brigade Force

ACR

Stryker BCT

ACR

Stryker BCT

Scout

Heavy UA

Light

Stryker BCT

Scoutc

43-Brigade Force

Type of Brigade 

Premodular Force

Heavy

ACR

Reserve

Number per Brigade Number of Brigades Number of Companies 
APPENDIX B THE ARMY’S PLAN FOR MODULARITY 71

tent than this comparison suggests. However, the Army 

has frequently reorganized its forces in the past, and CBO 

is not aware of historical research showing that such reorganizations have generally increased combat power independently of other changes (such as new equipment).12

In at least one case, research suggests that a reorganization 

significantly degraded the Army’s combat power.13

Implications for the Army’s Ability to 

Sustain Extended Deployments

The effect that modularity will have on the Army’s peacekeeping ability is related to the number of additional 

units and personnel that the service will have available for 

extended deployments. Because CBO assumed that all 

combat forces are useful for sustaining extended deployments, the modularity plan should have a roughly similar 

effect on the Army’s ability to sustain forces overseas as it 

does on the Army’s ability to fight wars. That effect will 

be slightly larger, however, because the modularity plan 

shifts more major combat units into the active component. Active units can be rotated through deployments at 

a higher rate than reserve units can. As such, the additional 25,000 to 45,000 active personnel in major combat units produce a greater improvement—on a persoldier basis—in the Army’s ability to sustain an extended 

deployment than the 20,000 fewer reserve personnel in 

major combat units decrease that ability.

CBO estimates that with a 43-brigade force, about 5,000 

to 7,000 additional personnel could be sustained overseas 

for extended deployments, and with a 48-brigade force, 

about 9,000 to 11,000 additional personnel would be 

available. Those numbers represent improvements of 

about 5 percent and 8 percent, respectively, in the peacekeeping ability of the current force.

If the Army requires additional EAD support forces for 

the increased number of modular units—as is likely—

some of those support forces can also be used to sustain 

extended deployments. However, it is also likely that the 

modularity plan will require the Army to depend more 

on the reserves to provide EAD support units. Those 

units will rotate through extended deployments at the 

lower rate used for reserve units and will contribute relatively little to the total number of personnel who can be 

sustained overseas for an extended deployment. The exact 

effect will depend greatly on how the Army achieves 

modularity—whether it receives additional end strength, 

whether it finds TDA/TTHS positions to eliminate, and 

how it chooses to support National Guard forces.

Another consideration is that at some level of dependence 

on the reserve component, the Army would no longer be 

able to rotate active combat units at the higher activecomponent rate while supporting them with reserve EAD 

units that rotated at a slower rate. (Such a system would 

require either that the Army have more reserve EAD support units than active combat units or that it rotate reserve units as frequently as active units, which would not 

be sustainable.) At that point, the Army would need to 

choose between having the deployment of active combat 

units be “bottlenecked” by the available supply of reserve 

EAD support units or rotating reserve units at a pace 

comparable with that of active units.

Implications for the Army’s

Dependence on the Reserve

Component

As discussed above, the modularity plan will increase the 

degree to which combat units in the active Army rely on 

EAD support units in the reserve component, unless the 

Army receives a substantial increase in active end strength 

or greatly reduces the number of personnel required to 

provide EAD support to combat units. Under CBO’s 

assumptions about the level of support that a modular 

force might require, up to 70 percent of the personnel 

needed to support the Army’s active combat forces would 

come from the reserve component, as opposed to 60 percent for the current force. 

12. That statement is not to imply that no reorganization has 

improved combat capability, only that it does not appear to be the 

case that reorganizations usually improve combat capability. The 

development of armored divisions, in particular, is widely considered to have greatly increased the combat power of formations 

equipped with tanks. Some historians also believe that the airmobile divisions of the Vietnam War era were similarly important 

for the combat power of formations equipped with helicopters.

13. In particular, the Pentomic division of the 1950s has subsequently 

been regarded as a seriously deficient organization plan. In U.S. 

Army Command and General Staff College, Combat Studies 

Institute, Sixty Years of Reorganizing for Combat: A Historical Trend 

Analysis, CSI Report No. 14 (Fort Leavenworth, Kan.: CSI, 

December 1999), an Army general is quoted as saying: “Every 

time I think of . . . the Pentomic Division I shudder. Thank God 

we never had to go to war with it.” That report assessed the Pentomic division as lacking “the capacity and capabilities to perform 

the basic warfighting functions necessary in combat.”
72 OPTIONS FOR RESTRUCTURING THE ARMY

In general (without considering the other possible effects 

of modularity), that increase in dependence would represent an additional 18,000 to 19,000 reserve personnel 

who would have to be mobilized and deployed for a 

major combat operation. Similarly, it would increase the 

number of reserve personnel who would need to be 

mobilized to support extended deployments by 3,000 to 

4,000 if the Army was fully committed (that is, if all of its 

forces were doing peacekeeping all of the time). That 

effect could be increased or decreased, however, by decisions that the Army might make. If the Army required 

additional active personnel to achieve its modularity plan, 

that effect would be greatly reduced. If the Army tried to 

expand to a 48-brigade force within its current endstrength limits, that effect would be increased.

Implications for Deployment Speed

To evaluate how modularity may affect the speed with 

which the Army can deploy forces, CBO used TOE data 

to compare the number of wheeled and tracked vehicles 

in current brigades and modular brigades. Those vehicles 

account for 75 percent to 80 percent of the weight of a 

heavy combat brigade, so such a comparison provides a 

reasonable way to assess whether the unit equipment in 

modular brigades will weigh more or less than that in current brigades.

According to the Army’s TOE data, a current armored 

brigade combat team (BCT) has about 1,100 wheeled 

and tracked vehicles, weighing a total of about 19,500 

tons. A current mechanized infantry BCT has roughly 

the same number of vehicles but with a total weight of 

about 17,500 tons. In the modular Army, a heavy BCT 

will have about 1,200 wheeled and tracked vehicles, 

weighing about 18,500 tons. Those numbers suggest that 

at the brigade level, modularity will not make the Army 

appreciably easier or more difficult to deploy.14

The situation is different at the division level. Modular 

divisions will have essentially the same division base as 

current divisions, but they will also have four BCTs instead of the current three BCTs. Each brigade and division base will have about the same weight of unit equipment in the modular force as in the current force, which 

suggests that if a modular division deployed with all four 

brigades, it would be more difficult to deploy than a current division with three brigades.

Because CBO does not know how the Army will allocate 

EAD support units to modular units, it is impossible to 

evaluate whether fully supported divisions, or entire 

corps, will be easier or more difficult to deploy than current forces are. If the Army allocates fewer support forces 

to each modular division and has a smaller, more flexible 

corps, the modular force as a whole may be much easier 

to deploy. If, however, the Army does not make substantial reductions in those support forces and corps, the 

modular force is unlikely to be easier to deploy than current forces are—and may even be harder to deploy.

14. Comparing those units by the square footage of their vehicles 

produces comparable results.
C

The Measures of Army Capability

Used in This Study

To analyze current and illustrative Army force structures, the Congressional Budget Office (CBO) used several different quantitative measures. This appendix 

discusses how the measures were generated and their significance.

The measures used in this analysis can be divided into 

four sets:

B The overall size and composition of the force—the number of personnel required in the active and reserve 

components; the total number of corps, divisions, and 

brigades in the force; and the number of fully supported combat brigades that the Army could deploy 

overseas to a contingency.

B The cost of the force—costs for military personnel, 

operations and maintenance, procurement of equipment, and continued modernization of that equipment, over four time periods: five years (2006 to 

2010), 10 years (2006 to 2015), CBO’s long-term 

projection period (2006 to 2022) and annually once a 

force structure has been implemented (also known as 

recurring costs).

B The force’s ability to fight wars—the number of combat 

brigades and active and reserve personnel that the 

Army would use for a notional major combat operation; the number of such operations that could be 

conducted simultaneously; and the average speed with 

which a single brigade, division, corps, or theater 

could be deployed to various locations overseas.

B The force’s ability to sustain extended deployments—the 

number of personnel and brigades that could be deployed for long periods using combat forces only from 

the active component or from both the active and 

reserve components, and in either case, the number of 

reserve personnel who would be mobilized to support 

those deployments.

Size and Composition of the Force

CBO’s measures of the size of the force show the number 

of major units in the force, with combat brigades separated into those that would be fully supported (that is, for 

which the Army would have a complete set of echelonsabove-division, or EAD, support units) and the total 

number of combat brigades (regardless of whether they 

would be fully supported). CBO’s measures also show the 

total number of personnel required, for the active and 

reserve components, to fully man the force. The total personnel requirement includes all major combat units, all 

EAD support units, all administrative and overhead 

units, and the allowance for trainees, transients, holdees, 

and students (TTHS).

To determine the number and type of personnel needed 

to man any given force, CBO constructed a model of the 

Army’s force structure. The model uses the number and 

types of major elements (brigades, divisions, corps, and 

theaters) as inputs, generating the number of personnel in 

major combat units, EAD support units, administrative 

units, and TTHS positions as outputs. To the maximum 

degree possible, the model was based on the Army’s own 

rules and processes for determining personnel requirements.

The main sources for the model were Army databases 

containing the sizes of existing units and the Army’s alloAPPENDIX
74 OPTIONS FOR RESTRUCTURING THE ARMY

cation rules for the Total Army Analysis (TAA) process.1

The TAA process takes high-level guidance from the 

Office of the Secretary of Defense and uses it to generate 

a detailed blueprint for all of the Army’s units. That guidance generally takes the form of directives such as “The 

Army will maintain 10 active divisions” or “The Army 

will maintain 33 active combat brigades.” The TAA process allocates support units to Army forces using a series 

of rules for how EAD support units should be allocated, 

according to Army doctrine, and thus generates a total 

personnel requirement, along with a list of what types of 

units are needed in what quantities.2

 The final result of 

the process is the Army Structure Message, which incorporates the Army’s final decisions and is used to order 

changes to the Army’s set of units.

CBO’s model works by using various Department of Defense (DoD) and Army databases to establish the number 

of personnel required for each type of Army unit. It then 

uses the TAA allocation rules to determine the full set of 

support units necessary for each type of major combat 

unit.3

 Most of the allocation rules are based on fixed 

ratios—such as one corps support group per division—

and can be easily calculated. Some of the rules, however, 

are based on workload factors that are more difficult to 

determine. CBO was unable to obtain the Army’s set of 

workload factors and thus had to make assumptions 

about the appropriate values for those factors.4 With that 

done, it is possible to determine the marginal “cost”—in 

terms of personnel positions required—for each type of 

major combat unit. CBO’s model separates that cost into 

the number of personnel in the major combat unit itself 

and the number of personnel in the EAD support units.

CBO’s model includes the following types of units as 

major combat units:

B The theater (technically, the Army service component 

command headquarters),

B The corps (technically, the corps headquarters and 

headquarters company),

B The heavy division (technically, the arithmetic mean 

of the personnel requirement and the weight of the 

unit equipment in a Force XXI armored division, 

Force XXI mechanized division, Army of Excellence 

armored division, and Army of Excellence mechanized 

division),

B The heavy brigade (technically, the same arithmetic 

mean of the same types of brigades as was used for the 

heavy division),

B The light infantry division,

B The light infantry brigade,

B The airborne division,

B The airborne brigade,

B The air assault division,

B The air assault brigade,

1. The TAA process is a biennial process that the Army engages in to 

determine how many personnel and units it needs, of what types, 

and in which components. The process is described in more detail 

in U.S. Army War College, How the Army Runs: A Senior Leader 

Reference Handbook, 2003-2004 (2003), and John C.F. Tillson, 

John R. Brinkerhoff, and Robert Macgruder, Total Army Analysis 

2009 (TAA09): A Critical Review, IDA Document D-2809 (Alexandria, Va.: Institute for Defense Analyses, January 2003). The 

heart of the process is a large set of rules that attempts to formally 

codify Army doctrine.

2. CBO obtained a copy of those unpublished rules from the Army’s 

Force Development Directorate.

3. That process requires some iteration because many of the rules 

form extensive “chains.” For example, there are rules that specify 

how many and what type of artillery brigade headquarters should 

go with each division. Then there are second-order rules that specify how many and what type of artillery battalions should go with 

each artillery brigade headquarters. Then there are rules that specify how many and what types of signals, maintenance, ammunition, and other units should go with each artillery battalion. Ultimately, the presence of a requirement for a division will generate a 

requirement for all of those subordinate units, but the formal 

modeling involved is more complex.

4. The workload factors fall into three sets. The first set includes 

such workloads as the total number of Army personnel in a theater 

or the total tons of equipment that must be moved through a port. 

Those factors can be estimated using information available elsewhere in the model. The second set includes such workloads as 

estimated fuel consumption per day, the length of the main supply 

route, or the number of enemy prisoners of war taken. CBO estimated those by using Army planning documents, historical data, 

and other methods to make reasonable assumptions about what 

the correct values might be. The third set includes factors that 

CBO cannot estimate, such as the number of man-hours required 

for electronics maintenance or construction tasks. In those cases, 

CBO adjusted the relevant values so the model’s outputs would 

match the Army’s existing set of units.
APPENDIX C THE MEASURES OF ARMY CAPABILITY USED IN THIS STUDY 75

B The armored cavalry regiment,

B The heavy separate brigade (a National Guard heavy 

separate brigade),

B The separate infantry brigade (a National Guard light 

separate brigade),

B The Stryker brigade combat team, and

B The special forces group.

To properly capture the personnel positions required by 

unsupported National Guard combat forces, CBO also 

made provisions in the model to add combat units without support forces. To capture the personnel required for 

administrative and overhead positions, CBO added such 

positions at a set ratio (different for the active and reserve 

components) that reflected the relatively stable historical 

ratio of overhead and TTHS positions to deployable 

forces.

Thus, to establish the total personnel requirement for a 

force structure, it is only necessary to enter into CBO’s 

model the number of major combat units, by type and 

component, and which of those units are supported (or 

unsupported) and to set what fraction of the EAD support units required by active combat units are in the 

active force (or the reserve component). When values corresponding to the Army’s current force are entered, the 

model produces the personnel levels of the current force.5

Cost of the Force

CBO used two primary approaches to estimate the costs 

of each alternative force structure.6

 The first approach 

employed various sources of budgetary data to estimate 

the incremental cost of establishing and maintaining new 

units or eliminating current units. CBO estimated all of 

the operation and support costs for a force structure, 

including the costs associated with pay and benefits for 

personnel, spare parts, fuel, and other needs to operate 

and maintain forces. It also estimated the up-front costs 

of purchasing equipment for a new unit—effectively, the 

one-time, nonrecurring procurement costs for the new 

unit.

CBO used a second approach to estimate the long-term 

costs of developing and purchasing new equipment to 

sustain the force. The Army’s investment program is 

intended to modernize units by giving them newer and 

better equipment than current forces have. Over time, 

that newer equipment replaces current equipment in the 

force. If the Army created or disbanded units, its need for 

investment funding over the long term would increase or 

decrease accordingly. Those investment costs are distinct 

from the up-front costs to equip a new unit initially.

By way of illustration, if the Army created a heavy division, it would need to spend money to equip the division 

with heavy armored vehicles, such as M1 Abrams tanks or 

M2 Bradley fighting vehicles. Those purchases would be 

one-time, up-front costs necessary to establish the division. Over time, however, the division would be modernized with newer equipment that is not yet developed and 

fielded, such as the equipment being developed as part of 

the Future Combat Systems program. The costs of modernizing equipment are longer term in nature. Similarly, 

if the Army eliminated a division, the costs of executing 

its investment program over the long term would decline 

because fewer pieces of new equipment would be needed 

to modernize a smaller force.

Ability to Fight Wars

Gauging the Army’s warfighting capability involves analyzing two key factors: the size of the force package (units 

and personnel) needed to conduct one or more major 

combat operations and the speed with which elements of 

that package can reach the theater of operations.

Force Package 

CBO measured warfighting ability by defining the size of 

the force necessary to fight a notional major combat operation and comparing that with the size of a particular 

force structure. For this analysis, a major combat operation is defined as one that requires a full theater, two 

5. Input values for the current force use the same premodularity 

structure of two theaters, four corps, 18 divisions, and 69 combat 

brigades described in Chapter 1. One corps is in the reserve component, as are eight divisions and 36 combat brigades. Fourteen 

National Guard brigades are left unsupported, with 15 separate 

brigades, a Stryker brigade, and three National Guard divisions 

considered fully supported. There are also five active and two 

National Guard special forces groups. Forty percent of the EAD 

support units required by active combat units are themselves in 

the active component. The result is 485,000 active personnel and 

555,000 reserve personnel.

6. CBO’s methods of estimating costs for this analysis are described 

in more detail in Appendix D.
76 OPTIONS FOR RESTRUCTURING THE ARMY

corps (each with an armored cavalry regiment), and six 

divisions, for a total of 20 combat brigades. The number 

of personnel associated with that force—and thus the 

number required for a major combat operation—could 

vary because the size of those elements and their support 

forces differ in the various alternatives that CBO analyzed. 

The number of personnel from the reserve component 

who would need to be mobilized and deployed for that 

major combat operation is based on the assumption that 

all of the combat units used in the operation would come 

from the active component. Consequently, the number of 

reserve personnel who would have to be mobilized and 

deployed to support the operation would include however many reserve personnel would need to be mobilized 

for EAD support units. Alternatives that place greater or 

lesser reliance on the reserve component for EAD support 

units will have greater or lesser need for reserve mobilization. Similarly, alternatives that require a smaller number 

of EAD support units will require less reserve mobilization. Because this measure includes only reserve personnel who would be mobilized and deployed, it excludes 

personnel backfilling for deployed active forces. As long 

as the Army continues the practice of backfilling, any 

major combat operation will necessitate that some reserve 

personnel be mobilized (but not deployed overseas) for 

that purpose.

In each alternative, the number of reserve personnel 

mobilized and deployed would have to be much greater if 

major combat units from the National Guard were used 

for the combat operation. Although the Army has not 

done that since the Korean War, it would be necessary in 

many of the alternatives that CBO analyzed if the Army 

had to engage in two major combat operations simultaneously. Thus, a second major combat operation would 

require proportionately more reserve personnel to be 

mobilized and deployed than the first operation would.

The number of major combat operations that a given 

force could execute equals the number of fully supported 

combat brigades in that force divided by the number of 

brigades required for a single major combat operation. 

Although that measure simply restates information given 

elsewhere in the analysis, CBO included it because it provides a different way of characterizing the Army—for 

instance, it is sometimes more helpful to think of the 

Army as having the ability to fight more than two wars 

than as having 55 fully supported combat brigades.

In actual practice, conducting a major combat operation 

requires corps and theaters as well as combat brigades. 

The Army’s current force—and most of the alternatives 

that CBO examined—do not have the additional corps 

and theaters that would be needed to fight more than two 

such operations. Even without those elements, however, 

the Army could reap substantial benefits from having 

more combat brigades and divisions than it needed to 

execute two major combat operations simultaneously. 

The first benefit is that a larger force would be able to 

use more active combat brigades and divisions and thus 

would not need to mobilize as many National Guard 

combat forces to fight simultaneous combat operations. 

The second benefit is that the Army could maintain 

peacetime commitments that it might otherwise not be 

able to carry out. For example, in the event of two simultaneous major combat operations, an Army with just 40 

combat brigades that had a three-brigade commitment in 

Afghanistan and the Balkans would have to choose between conducting one of the combat operations with 

fewer forces or terminating one of its other commitments 

and redeploying the forces that were employed there. A 

larger Army would not face that choice and would be able 

to maintain more peacetime commitments during major 

combat operations. In addition, since a significant goal of 

the U.S. military is to deter potential adversaries, a larger 

force may be seen as more credible and hence as a superior deterrent force.

For some alternatives, CBO reduced the size of the force 

assumed to be necessary for a major combat operation. 

It did so for alternatives whose proponents claim that the 

policies they advocate would allow much smaller ground 

forces to be as effective as—if not more effective than—

larger forces structured like the current force. For example, both Alternative 5 (the brigade-based Army) and 

Alternative 7 (the transformational Army) envision a 

corps-sized force of six combat brigades and a theatersized force of 12 combat brigades.

CBO cannot evaluate the validity of claims about the 

qualitative improvement that such policy choices might 

produce. However, reducing the size of the force for a 

major combat operation can illustrate the benefits for 

deployment speed and for the number of major combat 

operations that the Army could fight at one time. Of 

course, if those alternatives did not produce significant 

qualitative improvements in warfighting capacity, they 

would probably require larger force packages, potentially 
APPENDIX C THE MEASURES OF ARMY CAPABILITY USED IN THIS STUDY 77

eliminating the quantitative improvements in deployment speed or warfighting indicated in this analysis.

Deployment Speed 

CBO’s measure of deployment speed shows the time that 

would be required, once a decision to deploy troops had 

been made, to deploy a complete Army force to a distant 

theater of operation. That measure is an aggregate approximation in several respects: 

B It includes only the time required to deploy an Army 

force. In an actual military operation, units from other 

services would almost certainly be employed. The 

need to transport Air Force or Marine Corps units to a 

theater would increase the overall requirement for strategic lift, boosting the total time necessary to deploy a 

force.

B It averages the time required to deploy various types of 

Army forces for 10 different combinations of origins 

and destinations. Forces are assumed to come from the 

West Coast, Gulf Coast, or East Coast of the United 

States or from Europe. They are assumed to be deployed to various regions, represented by South Korea, 

the Philippines, Nigeria, Azerbaijan, Djibouti, and 

Uganda. CBO also considered deployment of light, 

medium, and heavy forces (although not all alternatives include all three types of forces).

B It covers the time needed to deploy all of the unit 

equipment and personnel associated with a particular 

force but assumes no additional time for other activities. Some military operations can begin before a force 

is fully deployed (as was the case with Operation Iraqi 

Freedom). Other operations may require a lengthy 

period after unit equipment and personnel have been 

deployed to build up stocks of fuel, ammunition, 

spare parts, and other items necessary to sustain the 

operation.

Using an approximate, aggregate measure of deployment 

speed, rather than estimating detailed deployment timelines for a number of specific scenarios, offers numerous 

benefits. The most important is that the aggregate measure incorporates a broad mix of destinations, which 

reduces the problem of dependence on extreme scenarios. 

Different deployment scenarios produce different results 

for a given policy change. For example, deployment destinations that are far inland favor airlift as a mode of transport, whereas deployment destinations on coasts favor 

sealift. Likewise, destinations can be close to or far away 

from prepositioned equipment. Thus, it is relatively easy 

to select a single scenario that will favor almost any particular policy choice. For instance, a scenario involving 

deployment to Azerbaijan—which has good air infrastructure but poor access to seaports, is far inland, and is 

relatively removed from prepositioned equipment—

makes the deployment of light or medium forces by air 

appear to be an attractive choice. By contrast, a scenario 

involving Djibouti—which has a coastal location with 

relatively good seaport access and is near a prepositioned 

set of equipment—makes afloat prepositioning of heavy 

equipment appear to be a good choice. A force that is 

optimized for one of those particular scenarios, however, 

may perform poorly in a different scenario. Since it is 

extremely difficult to predict where the next major U.S. 

military operation will be conducted, a force that is capable of performing well in a wide variety of scenarios is 

generally more useful than one optimized for any single 

scenario. By using the average of several origins and a 

wide variety of destinations, CBO’s measure of deployment speed is not scenario-specific.

No matter the analytical approach used, actual deployment times will always vary from any modeled deployment timeline. Actual forces tend to be deployed to 

unpredictable locations, are customized to meet the needs 

of unpredictable contingencies, and generally experience 

random incidents that increase the time required for 

deployment.7

Modeling Deployment. CBO began its modeling of 

deployment by evaluating whether a force could be deployed more quickly between a given origin and destination purely by airlift or with a mixture of airlift and sealift. Pure airlift deployment is a superior option in only a 

very small number of cases, involving a single light or 

medium brigade and specific combinations of origins and 

destinations. For that reason, almost all of CBO’s modeling used mixed airlift and sealift deployments.

7. For example, during the deployment of the 24th Infantry Division 

to Saudi Arabia for Operation Desert Shield, an engine failure on 

one of the fast sealift ships carrying equipment delayed the arrival 

of much of the division’s equipment by nearly a month. In Operation Iraqi Freedom, the arrival of the 4th Infantry Division and 

the 3rd Armored Cavalry Regiment was significantly delayed by 

the Turkish government’s decision not to allow U.S. forces to use 

its territory. Such events are effectively impossible to predict, and 

major deployments occur rarely enough that it is not useful to try 

to use statistical methods to estimate the effects of such events.
78 OPTIONS FOR RESTRUCTURING THE ARMY

CBO modeled airlift using planning factors and equations from the Air Force’s Air Mobility Command.8

 A 

critical factor in analyzing air deployment is the quality of 

air infrastructure in the destination theater. That quality 

is generally captured in a measure called “maximum on 

ground” (MOG), which represents the number of cargo 

aircraft that can usefully be accommodated at an airport 

at any one time. MOG is an abstract measure, because 

airports differ in ways that can be difficult to capture in a 

standardized set of objective measurements. Airports may 

be limited in their ability to receive aircraft by the number of parking spaces available for aircraft, the materielhandling equipment available, or other factors. In addition, with enough time, Air Force engineering units can 

generally increase an airport’s MOG. 

Over short periods, however, MOG is the primary limit 

on the speed with which the U.S. military can airlift 

cargo or passengers to a distant theater. The reason is that 

the U.S. fleet of strategic airlifters—with about 100 C-5 

Galaxy aircraft, 180 (programmed) C-17 Globemaster III 

aircraft, and potentially several hundred aircraft from the 

Civil Reserve Air Fleet—is very large relative to the air 

infrastructure in most potential theaters of operation. As 

such, the United States’ ability to deliver cargo for military operations in a single theater is generally limited not 

by the number of cargo aircraft available but by the quality of the air infrastructure in that theater.9

 For that reason, CBO’s analysis does not consider alternatives that 

would increase the size of the U.S. strategic airlift fleet—

such an increase would not improve deployment times to 

MOG-limited theaters.

CBO modeled sealift using data provided by the Navy’s 

Military Sealift Command (MSC).10 That modeling 

assumes that the majority of unit equipment will be 

transported by either fast sealift ships (FSSs) or large, 

medium-speed roll-on/roll-off ships (LMSRs). FSSs are 

large, high-speed vessels with the capacity to transport 

containers and vehicles; LMSRs are large, medium-speed 

vessels with the capacity to carry vehicles.11 MSC also 

maintains a fleet of slower, smaller roll-on/roll-off ships, 

but they take longer to activate (most MSC ships are not 

kept in a fully active status during peacetime), carry less, 

and move more slowly than FSSs and LMSRs do. Thus, 

they contribute relatively little to MSC’s capability to 

deploy large numbers of vehicles—which make up the 

bulk (by weight) of an Army unit’s equipment that would 

need to be deployed in any major military operation. 

In CBO’s model, deployment by sealift requires time to 

activate ships, time to move the ships to the relevant 

ports, time for units to reach the ports (if that takes 

longer than activating and moving the ships to port 

does), time to load the ships, time to sail them to their 

destination ports, time to unload the ships, time to reorganize units (matching personnel up with equipment), 

and time for the units to move from the port to their area 

of operations. Prepositioned sets of equipment are modeled as ships that begin in a different location and that do 

not require movement to port, loading time, or time for 

the units to move to port (since prepositioned equipment 

remains stored on ships during peacetime).

CBO established the requirement for strategic lift in its 

modeling by dividing that requirement into two portions: 

passengers and unit equipment. The number of passengers for a given force equals the number of personnel in 

the force, and all passengers are assumed to be airlifted to 

a theater (consistent with the military’s practice in most 

recent operations). Unit equipment has both a weight requirement, used for air deployment, and a square-footage 

requirement, used for sea deployment.12 CBO consulted

8. Department of the Air Force, Air Mobility Command, Air Mobility Planning Factors, Air Force Pamphlet 10-1403 (December 18, 

2003), available at www.e-publishing.af.mil/pubfiles/af/10/

afpam10-1403/afpam10-1403.pdf.

9. It is, however, true that the United States’ ability to deliver cargo 

to multiple theaters can be limited by the number of cargo aircraft 

available.

10. Those data include the fact sheets available at www.msc.navy.mil/

factsheet/.

11. Roll-on/roll-off cargo ships are sometimes described as floating 

parking garages. They are the preferred type of ship for transporting most of an Army unit’s equipment, as the majority of Army 

vehicles cannot be shipped in the standard containers that dominate the civilian shipping market. The capacity of roll-on/roll-off 

shipping is generally the main constraint in deploying Army 

forces—the civilian shipping industry has relatively little roll-on/

roll-off capacity compared with the Army’s needs, and the Army 

requires relatively little container capacity compared with the 

capacity of the civilian sector.

12. Technically, cargo aircraft are limited in how much they can carry 

either by the weight of the equipment or by the size of the equipment. Equipment that is light but bulky is said to “cube out” an 

aircraft, meaning that it fills up the cubic volume of an airlifter. To 

reflect that, CBO followed Air Mobility Command’s planning 

factors, which use an average payload that airlifters could realistically be expected to carry, rather than using the maximum payload 

that airlifters could theoretically carry. A similar factor is necessary 

for sealift to reflect the fact that equipment cannot be packed in 

ships at the maximum density possible but must instead be spaced 

widely enough to allow for walkways, tie-downs, and so forth.
APPENDIX C THE MEASURES OF ARMY CAPABILITY USED IN THIS STUDY 79

a variety of DoD and Army databases to determine the 

weight and square footage of each of the units that would 

compose any given force and aggregated them to calculate the total weight or square footage of the force.13

CBO avoided creating completely new types of units for 

the alternatives in this study. In most cases, the different 

types of units were created by building up larger, higherlevel units (such as divisions and corps) from smaller 

“building blocks” (such as battalions) that exist in the 

current force. The only exception was Alternative 5 (converting to a brigade-based Army), in which the units 

described by retired Army Colonel Douglas MacGregor 

could not easily be built up from existing units. For that 

alternative, CBO used averages of unit equipment weight 

and square footage per person for different types of units. 

For example, that option’s combat maneuver group, with 

5,000 personnel, uses a per-person factor for equipment 

weight that represents the average for all existing armored 

units in the Army. Similarly, that option’s early-deploying 

support group uses a per-person factor that is based on all 

existing Army logistics units.

Illustrating Deployment. For illustrative purposes, CBO 

compared cumulative deliveries of equipment over a sixmonth period by airlift or sealift (see Figure C-1).14 The 

notional comparison uses a fleet of 180 C-17 aircraft and 

MSC’s fleet of FSSs and LMSRs to transport cargo from 

Savannah, Georgia, to Djibouti. The set of Army equipment prepositioned at Diego Garcia in the Indian Ocean 

is also assumed to be used. Airlift is assumed to operate 

either with or without constraints. With no MOG limitations in the theater, the C-17 fleet could transport about 

5,000 tons of equipment per day; with a MOG of three 

(fairly typical for a poorly developed or small country), 

the C-17 fleet could deliver about 1,000 tons a day. 

Because of the nature of sealift, significant time can elapse 

before any sealift ships arrive in a theater. When they do 

arrive, however, they deliver large quantities of cargo. 

Given the relatively limited number of ships that carry 

most of the cargo for an operation and the relatively long 

times needed for a ship to make a first, second, or third 

trip, the amount of materiel delivered by sealift over time 

shows a pronounced stair-step pattern in Figure C-1, as 

opposed to the smooth pattern produced by smaller but 

more-frequent airlift deliveries.

Figure C-1 helps illustrate several points about deployment. First, it shows why mixed air and sea deployments—rather than pure air deployments—are used for 

any large force. The capacity of sealift is so big relative to 

that of airlift that beyond the first two weeks of an operation (when no ships will have arrived yet), sealift will 

always provide a greater percentage of the total lift capacity than airlift will. That is especially true in real-world 

situations with limited MOG. In this example, a heavy 

division plus all of its EAD support units, with about 

180,000 tons of unit equipment, require about 25 to 30 

days to deploy, using prepositioned equipment. Attempting to deploy the same force purely by air would take 35 

to 40 days in the absence of MOG limitations and 180 to 

185 days with MOG limitations.

Second, Figure C-1 shows why using sealift can greatly 

reduce the differences between the times needed to deploy various kinds of units. In essence, the reason is that 

ships travel at the same speed regardless of what type of 

unit equipment they carry. In this scenario, between day 

25 and day 30, more than 400,000 tons of equipment 

would arrive in the theater by ship (excluding prepositioned equipment). That arrival time would be roughly 

the same (with some small difference because of loading 

time) regardless of whether the ships were carrying the 

equipment of a light unit or a heavy unit. About 400,000 

tons would be enough to encompass either a light division or a heavy division, which means that there would be 

no meaningful difference between the times required to 

deploy the two types of divisions by sea.15

Finally, Figure C-1 illustrates the effect of prepositioning 

sets of equipment on ships. Such sets do not increase 

MSC’s total transport capability over long periods of 

time, but they accelerate the point at which the first 

deliveries of unit equipment arrive in a theater. The long 

time gap before any transport ships arrive is one of the 

primary disadvantages of sealift. Prepositioning sets of 

13. Those sources include the Conventional Forces Database 

(CFDB), the Type Unit Characteristic (TUCHA) database, and 

Department of the Army, Military Traffic Management Command, Transportation Engineering Agency, Deployment Planning 

Guide: Transportation Assets Required for Deployment, Pamphlet 

700-5 (May 2001).

14. To make the comparison, CBO converted the square footage of 

the equipment transported by ships into tons. Such a conversion 

is an approximation used for purposes of simplicity.

15. Because this is a notional example, the discussion excludes the 

possibility that Djibouti’s seaports could experience capacity constraints (similar to the effect of MOG on airports). Such capacity 

constraints can exist for seaports, although they are rarer and generally less severe than for airports.
80 OPTIONS FOR RESTRUCTURING THE ARMY

Figure C-1.

Amount of Equipment Deployed over Time by Airlift or Sealift

(Thousands of tons)

Source: Congressional Budget Office.

Notes: MOG = maximum on ground (a measure that represents the number of cargo aircraft that can usefully be accommodated at an airport 

at any one time).

This figure shows deliveries from Savannah, Georgia, to Djibouti in East Africa using 180 C-17 aircraft or Military Sealift Command’s 

fleet of fast sealift ships and large, medium-speed roll-on/roll-off ships. Prepositioned equipment is assumed to come from Diego 

Garcia in the Indian Ocean.

equipment on ships narrows the gap greatly, reducing 

that disadvantage of sealift. In fact, because such prepositioned sets are normally configured for heavy forces, and 

because large light forces are generally deployed by sea, in 

some cases prepositioned heavy units could arrive in a 

theater before light units did.

Ability to Sustain Extended

Deployments

The final set of measures in this analysis—ability to 

sustain a long deployment—were calculated using the 

method described in CBO’s September 2003 paper An 

Analysis of the U.S. Military’s Ability to Sustain an Occupation of Iraq. Unlike in that paper, however, the number of 

brigades and personnel that can be sustained for extended 

deployments in this study reflects the total capacity of the 

Army, not the additional capability beyond what the 

Army is already using to sustain its current commitments. 

In addition, this analysis excludes the Marine Corps’ ability to contribute to extended deployments (because it 

does not examine policy options for the Marine Corps).

The total number of personnel and brigades that the 

Army could keep deployed indefinitely reflects certain 

assumptions about how the Army would manage long 

deployments. In particular, this set of measures assumes 

that the Army would use rotational deployments of units 

(in other words, that the Army would deploy entire units 

for a certain period, at which point a new unit would be 

deployed to replace the first unit). The Army has used 

rotational deployments for all of its peacekeeping and 

occupation missions in the recent past, although it does 

use other forms of deployment for some of its commitments.16

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

Shipping from the United States

Equipment Prepositioned at Sea

Unconstrained Air Delivery

Constrained Air Delivery (MOG of 3)

Days

16. For example, the Army permanently bases several units (the 8th 

Army and the 2nd Infantry Division) in South Korea but rotates 

individual personnel through those units. Most of those personnel 

serve one-year tours unaccompanied by their families.
APPENDIX C THE MEASURES OF ARMY CAPABILITY USED IN THIS STUDY 81

This set of measures also assumes that Army deployments 

would be limited by the need to rotate units out of a theater and provide them with enough time at their home 

station to recover from their deployment (allowing personnel to take leave, refurbish equipment, and so forth) 

and to prepare for their next deployment (including completing the extensive series of training exercises that the 

Army requires of units before certifying them as fully 

ready). For active units, that assumption means that the 

Army would be able to keep one unit deployed for every 

three or four units in the force. (The exact ratio that the 

Army needs is uncertain, which is why CBO used a range 

for that value.) For units in the reserve component, the 

Army is bound by a DoD policy that such units should 

not be mobilized more than once in six years. The Army 

could rotate active and reserve units through theaters at 

higher rates, but that practice is generally considered 

unsustainable by the Army, DoD, and most external 

observers because it can lead to problems with retaining 

personnel and maintaining the readiness of units. Thus, 

although higher rates are possible, they would be appropriate only for operations that were fairly short or in 

which force levels were expected to decline over time.

In this analysis, the level of reserve mobilization needed 

to support an extended deployment assumes that the 

Army would commit the maximum level of forces that 

could be sustained. If the Army committed less than that, 

the necessary level of reserve mobilization would be 

lower. In general, the Army prefers to use active units 

before mobilizing and employing reserve units. As such, 

if the Army had a relatively small set of commitments, the 

fraction of a deployed force that would be composed of 

reserve units would be lower than for a deployed force 

that required the Army’s full ability to sustain extended 

deployments. 

If the Army had to provide larger forces to sustain commitments, the fraction of its deployed force that would be 

composed of reserve units would rise steadily, but slowly, 

until the point at which the Army had used all of the 

capability that active combat units could provide. At that 

point, all additional capability would have to come from 

employing National Guard combat units. Since such 

units are composed entirely of reserve personnel, employing them would greatly increase the fraction of reserve 

personnel that the Army would need to mobilize to sustain a deployment.

D

How CBO Estimated the Costs of

Options for Restructuring the Army

The cost estimates for the options described in this 

study have two major components: the investment costs 

or savings that would arise over the 2006-2022 period 

from equipping and modernizing the forces postulated in 

each option, and the operation and support (O&S) costs 

or savings associated with the day-to-day operations of 

the restructured forces. This appendix describes how the 

Congressional Budget Office (CBO) estimated those 

costs. The estimates represent incremental changes—the 

costs or savings that would result from an option relative 

to the cost of maintaining and modernizing the Army’s 

premodularity force structure. (The changes are not relative to the cost of the Army’s plans for a modular force 

because specific details about those plans were not available to CBO.)

All of the estimates are presented in 2006 dollars. Although that treatment removes the effects of inflation, it 

does not account for the fact that a dollar is worth less 

today than it will be tomorrow (because of the possibility 

of investing and earning a return on that dollar in the interim). A common analytic practice, for a stream of costs 

that vary over time, is to discount the costs to estimate 

their net present value (that is, the size of the equivalent 

lump sum today).1 However, CBO chose not to develop 

net-present-value calculations for this analysis because 

such calculations are rarely used in the context of national 

defense and would be difficult to compare with standard 

sources of information about the Department of Defense’s (DoD’s) budget.

CBO collected data from a wide range of sources to construct cost factors and estimates for the alternatives in this 

study. Because the actual costs or savings from restructuring the Army depend on specifics about the size and type 

of units involved (see Appendix C), and because this 

analysis includes a large number of options and unit 

types, CBO developed both detailed methods and generalized cost factors that could be applied to all of the 

options. 

Methods for Estimating 

Investment Costs

Investment costs include the cost of developing and buying weapon systems to modernize Army forces as well as 

the cost of purchasing today’s equipment (including such 

items as generators and trucks) for newly formed units. 

CBO estimated both types of investment costs using data 

from DoD’s Future Years Defense Program for fiscal years 

2005 to 2009, Congressionally mandated reports (called 

Selected Acquisition Reports) prepared by DoD for 

major weapon systems, and current-year and prior-year 

budget-justification materials.

Costs of Equipment to Modernize the Force

For each option in this study, CBO estimated the costs 

of developing and buying new equipment to sustain the 

force over the long run (through 2022) by modifying 

CBO’s long-term projection of the Army’s investment 

requirements (as published in The Long-Term Implications 

of Current Defense Plans: Detailed Update for Fiscal Year 

2005, September 2004). In that report, CBO projected 

the individual resource demands for major weapon systems over the 2005-2022 period using the Army’s longterm plans for specific programs as spelled out in the 

sources described above. Investment costs for other items 

APPENDIX

1. The calculation of present value depends on the rate of interest. 

For example, if $100 is invested on January 1 at an annual interest 

rate of 5 percent, it will grow to $105 by January 1 of the next 

year. Hence, with a 5 percent annual interest rate, the sum of 

$105 payable in a year has a present value of $100. 
84 OPTIONS FOR RESTRUCTURING THE ARMY

(such as artillery rounds, radios, and relatively low cost 

modifications to systems already in use) were estimated 

on the basis of trends in their funding since 1980 and the 

relationship between that funding and spending for 

major programs.

CBO developed projections for the alternatives in this 

study by altering the individual programs that make up 

the Administration’s plans according to how they would 

by affected by the force structure in each alternative. For 

example, CBO increased the quantities of major systems 

to be purchased when an alternative proposed adding 

forces—and reduced them when an alternative proposed 

cutting forces—by adjusting the number of years of fullrate production. (For most programs, a year of full-rate 

production is equivalent to about the amount of equipment required to equip one to two divisions.)

That general rule did not apply in some cases, however. 

In most of the alternatives, CBO did not modify the 

Army’s development and procurement plan for the Future Combat Systems (FCS) program. Because of the 

large annual funding requirements and length of that 

program, CBO assumed that it would not be feasible to 

increase or decrease the planned long-term procurement 

rate of two brigade sets a year over the 2006-2022 period. 

For options that would terminate the FCS program (Alternatives 5 and 6), CBO assumed that the Army would 

remanufacture existing ground combat vehicles and modernize them at rates needed to sustain equipment levels at 

a “steady state.”2

 CBO used a similar assumption to estimate requirements for the UH-60 Blackhawk helicopter 

program in all of the options.

In the options that would emphasize precision munitions 

(Alternatives 1B and 7), CBO increased the annual quantities of munitions such as the Guided Multiple-Launch 

Rocket System rocket and the Excalibur artillery munition. Procurement quantities for other systems, such as 

electronics, were adjusted by scaling projected annual 

funding by the change in the number of active combat 

brigades under the option. In cases in which the procurement quantity of a weapon system is not closely tied to 

the size of combat forces, CBO did not change the projection of funding.

Costs of Current Equipment for New Units 

A number of alternatives in this study would increase the 

size of the Army by creating new units. CBO estimated 

the cost to equip those units using the Army’s Tables of 

Organization and Equipment (TOEs), which list all of 

the equipment that each specific unit needs to perform its 

mission, and equipment prices found in Army budget 

materials or supply catalogs. For options (such as Alternatives 4 and 6) that would create new types of divisions, 

CBO developed a substitute TOE by combining TOEs 

for existing units to estimate the requirement for new 

equipment.

Methods for Estimating 

Operation and Support Costs

The estimates of O&S costs or savings in this study represent the difference between the costs for routine day-today operations and maintenance of the Army’s current 

force and those costs for each alternative. The estimates 

do not include any costs for contingency operations that 

might arise. CBO estimated three categories of O&S 

costs:

B Personnel costs include pay and allowances for all 

personnel assigned to a unit. CBO calculated those 

costs using the number of personnel authorized for 

each unit and data from Army pay tables. Personnel 

costs also include the cost to recruit and train new service members over time as assigned personnel transfer 

to other units or leave the Army. CBO calculated the 

cost to recruit and train personnel by deriving per capita costs from Army budget data and multiplying 

them by the number of personnel expected to rotate 

into units. 

B Equipment operating costs are the costs to run and 

maintain a unit’s equipment, including expenses for 

fuel, consumable supplies (such as air filters and seals), 

repair parts, and ammunition. Data on the costs to 

operate each type of equipment were derived from the 

Army’s Operating and Support Management Information System, a relational database that contains information about historical O&S costs for more than 500 

weapon systems used in Army units (active, Guard, 

and Reserve).

B Other unit and indirect support costs are indirect 

expenses that are allocated to units as well as training 

costs other than those to operate equipment. This cat2. For each alternative, CBO estimated the total inventory of systems that the force would require and constructed a procurement 

profile that would keep the average age of that inventory stable 

indefinitely.
APPENDIX D HOW CBO ESTIMATED THE COSTS OF OPTIONS FOR RESTRUCTURING THE ARMY 85

egory includes such costs as base operations, facilities 

maintenance, utilities, civilian labor, contracted services, administrative and overhead functions, mission 

travel, and other logistics services. CBO estimated 

those costs using per capita factors developed from 

Army budget data. 

Results of the Cost Analysis

Using the methods described above, CBO estimated both 

types of investment costs and all three categories of operation and support costs for each of the alternatives in this 

analysis. Those costs are detailed in the rest of this appendix and summarized in Table D-1.

Alternatives That Would Increase the Size 

of the Army

As explained in Chapter 2, the first set of options would 

expand the Army’s combat forces by adding two divisions 

to the active component. 

Alternative 1A would add about 78,000 personnel to the 

Army: 57,000 active and 21,000 reserve. CBO estimates 

that the investment costs associated with implementing 

Alternative 1A would total $31 billion over the 2006-

2022 period—about $16 billion to outfit the new units 

with current equipment and $15 billion to modernize 

them thereafter. With the time needed to create the units 

accounted for, the additional O&S costs associated with 

this option would total $21 billion between 2006 and 

2010, $95 billion over the 2006-2022 period, and almost 

$7 billion annually thereafter, CBO estimates. Of the 

$95 billion in added O&S costs through 2022, personnel 

costs would account for about $62 billion, or 65 percent.

Alternative 1B would add two divisions to the active 

component without appreciably increasing the size of the 

Army by eliminating all short-range air-defense units, 

doing away with some corps-level field artillery units, and 

restructuring the remaining field artillery units. Overall, 

those changes would add about 6,000 active personnel to 

the Army. CBO estimates that the net investment costs 

associated with implementing Alternative 1B would total 

$34 billion over the 2006-2022 period—about $15 billion to outfit the new units with today’s equipment and 

$19 billion to modernize them later. Additional O&S 

costs for those units—net of savings from not operating 

the eliminated units—would total $7 billion over the 

2006-2010 period (after accounting for the time needed 

to create the units), a little more than $20 billion over the 

2006-2022 period, and just over $1 billion per year thereafter. Equipment operating costs and other unit and indirect support costs account for about 60 percent ($12 billion) of the additional operation and support costs over 

the 2006-2022 period.

Alternatives That Would Reduce Dependence 

on the Reserve Component

Alternatives 2 and 3 would lessen the Army’s need to mobilize reserve units to support combat units in the active 

component. 

Alternative 2 would move support units that are necessary for peacekeeping operations (such as military police) 

from the reserve component to the active Army and 

transfer units that are less useful for peacekeeping (such as 

artillery units) to the reserves. Overall, this option would 

increase the number of personnel in the active component by about 28,000 and reduce the number of reserve 

personnel by 24,000. Alternative 2 would not require additional investment beyond that projected for the current 

force, but it would result in higher operation and support 

costs, on net. Those additional costs would total almost 

$9 billion over the 2006-2010 period (accounting for the 

time needed to implement the changes), $27 billion over 

the 2006-2022 period, and almost $2 billion a year thereafter, CBO estimates. About $26 billion of the incremental cost through 2022 represents personnel costs. Equipment operating costs for the force would decline by $11 

billion, because units with high equipment operating 

costs would move to the reserves, and support units with 

lower equipment operating costs would be placed in the 

active Army. However, other unit and indirect support 

costs would increase by $11 billion. About $4 billion of 

that rise would result from higher health care costs ($2 

billion) and higher military construction costs ($2 billion)—both related to shifting more personnel into the 

active component. The other $7 billion would result 

from the fact that the units moving to the active Army 

have higher indirect support costs than the units moving 

to the reserve component and from the fact that some 

other indirect expenses increase when personnel levels in 

the active component rise. 

Alternative 3 would eliminate the active Army’s dependence on reserve support units for both peacekeeping and 

warfighting by adding enough personnel to the active 

component to create support units for all of its combat 

units. Overall, this option would add about 312,000 personnel to the active Army and cut 260,000 reserve per-
86 OPTIONS FOR RESTRUCTURING THE ARMY

Table D-1.

Summary of Incremental Costs or Savings for Options to Restructure the Army

(Billions of 2006 dollars)

Source: Congressional Budget Office.

a. CBO did not project recurring investment costs because they depend on a host of decisions that CBO could not estimate or predict. (Unlike 

military pay or operations and maintenance costs, future modernization plans can be highly variable and are influenced by such things as 

technological advances, defense strategy, and actions by other nations or groups.) CBO’s estimates of investment costs through 2022 are 

based on the Administration’s current plans, but those plans do not extend indefinitely into the future.

129 605 a

398 1,488 99

___ ____ ___

Total 527 2,092 99

+17 +31 a

+21 +95 +7

___ ____ __

Total +37 +127 +7

+16 +34 a

+7 +20 +1

___ ___ __

Total +23 +54 +1

00 a

+9 +27 +2

__ ___ __

Total +9 +27 +2

00 a

+51 +333 +26

___ ____ ___

Total +51 +333 +26

Alternative 4: Organize Stabilization and Reconstruction Divisions

+2 -14 a

-4 -18 -1

__ ___ __

Total -2 -32 -1

Alternative 5: Convert to a Brigade-Based Army

-14 -176 a

-28 -138 -10 ___ ____ ___

Total -42 -314 -10

Alternative 6: Convert to an Expeditionary Army

+25 -79 a

+10 +45 +3

___ ___ __

Total +35 -34 +3

Alternative 7: Convert to a Transformational Army

-6 -24 a

-34 -166 -12 ___ ____ ___

Total -40 -190 -12

Alternative 3: Eliminate the Army’s Dependence on Reserve Support Units

Investment

2006-2010 2006-2022 Costs in 2022

Total Costs Annual Recurring

Operation and support

Current (Premodular) Force

Alternative 1A: Add Two Active Divisions

Alternative 1B: Add Two Divisions by Reducing Support Forces

Alternative 2: Reallocate Support Forces Between the Active and

Reserve Components

Investment

Operation and support

Investment

Operation and support

Investment

Operation and support

Investment

Operation and support

Investment

Operation and support

Investment

Operation and support

Investment

Operation and support

Investment

Operation and support
APPENDIX D HOW CBO ESTIMATED THE COSTS OF OPTIONS FOR RESTRUCTURING THE ARMY 87

sonnel. Alternative 3 would not require further investment beyond that projected for the current force because 

it would not create additional units. It would result in 

higher O&S costs, however. CBO estimates that those 

added costs would total $51 billion over the 2006-2010 

period (accounting for the necessary transition time), 

$333 billion over the 2006-2022 period, and $26 billion 

annually after that. Personnel costs would make up more 

than 70 percent (almost $240 billion) of the additional 

O&S costs through 2022. 

Alternatives That Would Create New Types of Units

The last four options that CBO analyzed (Alternatives 4 

through 7) would restructure the Army by creating different types of units that reflect a variety of concerns and 

proposals.

Alternative 4 would convert two active Army divisions 

into several dedicated peacekeeping divisions. Overall, 

this option would cut 2,000 personnel from the active 

component and 9,000 from the reserves. Implementing 

this alternative would produce investment savings of 

approximately $14 billion over the 2006-2022 period, 

CBO estimates. Although initially outfitting the new 

units would cost almost $5 billion, the Army’s modernization costs would be reduced by $19 billion because the 

force that would eventually have to be modernized would 

be smaller and less focused on high-technology weaponry 

intended for conventional warfighting. O&S costs would 

also be lower under this alternative, CBO estimates—not 

only because the force would be smaller but also because 

the equipment in the peacekeeping divisions would be 

less costly to operate. As a result, this option would 

reduce the Army’s O&S costs by just over $4 billion 

through 2010 (once the option had been implemented), 

$18 billion over the 2006-2022 period, and a little more 

than $1 billion per year thereafter. Of the $18 billion 

reduction over the 2006-2022 period, about $5 billion 

would result from lower personnel costs, $7 billion from 

lower equipment operating expenses, and $6 billion from 

lower costs for other unit expenses and indirect support.

Alternative 5 would reorganize the Army by eliminating 

its higher-level command structures and organizing the 

service into a number of autonomous brigade-sized combat groups. This option would not affect the number of 

active-duty personnel in the Army but would reduce the 

number of reserve personnel by 383,000. Those changes 

would produce total investment savings of $176 billion 

over the 2006-2022 period, CBO estimates, primarily 

from canceling the Future Combat Systems program as 

well as from having fewer combat forces to modernize in 

the future. Because Alternative 5 would cut the size of the 

reserves significantly, operation and support costs would 

also decline—by a total of $28 billion through 2010 

(accounting for the time needed to reduce reserve forces), 

$138 billion over the 2006-2022 period, and $10 billion 

annually after that. Of the $138 billion in O&S savings 

over the 2006-2022 period, $69 billion would result 

from lower personnel costs, $23 billion from lower equipment operating expenses, and $46 billion from lower 

costs for other unit expenses and indirect support.

Alternative 6 would eliminate the corps as a command 

structure and reorganize the Army into a series of expeditionary task forces similar to Marine expeditionary forces. 

Those changes would add 21,000 active personnel and 

20,000 reserve personnel to the Army. This option would 

also purchase additional sealift assets and sets of equipment to preposition on ships near potential theaters of 

conflict. CBO estimates that the investment savings associated with implementing this alternative would total 

almost $80 billion over the 2006-2022 period. Outfitting 

the new units and buying prepositioned equipment 

would together cost $21 billion, and purchasing additional sealift ships would cost almost $9 billion; those 

costs would be more than offset by savings from canceling the Future Combat Systems program. Although this 

option would reduce investment costs, it would increase 

operation and support costs, CBO estimates, because of 

the higher personnel levels and the larger number of sealift ships. Those additional O&S costs would total $10 

billion over the 2006-2010 period (once units had been 

reorganized), $45 billion through 2022, and $3 billion 

per year thereafter, CBO estimates. Personnel costs would 

account for about 55 percent ($24 billion) of the additional O&S costs over the 2006-2022 period. 

Alternative 7 would reorganize the Army to take advantage of recent advances in communications networks, 

precision-guided munitions, and sensors. The Army 

would have fewer divisions, and the mix of divisions 

would be shifted to lighter forces and special forces 

groups. Overall, those changes would reduce the number 

of active personnel by 115,000 but leave the number of 

reserve personnel unchanged. Implementing Alternative 

7 would lower the Army’s investment costs by $24 billion 

over the 2006-2022 period, CBO estimates, primarily 

because there would be fewer combat forces to modernize. Reducing the number of active personnel would also 
88 OPTIONS FOR RESTRUCTURING THE ARMY

lower O&S costs—by a total about $34 billion through 

2010 (accounting for the necessary transition time), $166 

billion over the 2006-2022 period, and $12 billion annually thereafter, CBO estimates. Of that $166 billion in 

O&S savings, approximately $103 billion would result 

from lower personnel costs, $16 billion from lower equipment operating expenses, and $46 billion from lower 

costs for other unit expenses and indirect support.

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