United States Government Accountability Office

GAO Report to Congressional Committees

AVIATION SECURITY

TSA’s Staffing 

Allocation Model Is 

Useful for Allocating 

Staff among Airports, 

but Its Assumptions 

Should Be 

Systematically 

Reassessed 

February 2007 

 

GAO-07-299 
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

February 2007

AVIATION SECURITY

TSA’s Staffing Allocation Model Is Useful 

for Allocating Staff among Airports, but 

Its Assumptions Should Be 

Systematically Reassessed 

Highlights of GAO-07-299, a report to 

congressional committees 

The Transportation Security 

Administration (TSA) has identified 

the transportation security officer 

(TSO) workforce as its most

important asset in securing 

commercial aviation. TSOs screen

passengers and baggage to prevent

dangerous items onboard aircraft. 

In response to an Intelligence

Reform and Terrorism Prevention 

Act of 2004 requirement to develop

standards for TSO staffing, TSA 

developed a staffing model to guide 

its TSO allocations across airports. 

The act also required GAO to

analyze TSA’s staffing standards. 

GAO analyzed (1) how TSA ensures

its model provides a sufficient TSO

staff to perform screening and (2) 

how TSA deploys its TSOs and 

factors that affect deployment. 

GAO analyzed data and reviewed

documentation about the model 

and discussed it with TSA 

headquarters officials and TSA 

officials at 14 airports. 

What GAO Recommends

GAO recommends that the

Secretary of the Department of 

Homeland Security (DHS) direct 

the Assistant Secretary for 

Transportation Security to (1) 

establish a mechanism to ensure 

periodic assessment of model

assumptions and (2) establish a 

policy for when TSOs can be used 

to provide operational support. 

DHS reviewed a draft of this report

and concurred with GAO’s findings 

and recommendations. 

TSA aims to ensure that its Staffing Allocation Model provides a sufficient 

number of TSOs to perform passenger and checked baggage screening by:

(1) building assumptions into its allocation model that are designed to 

calculate the necessary levels of TSOs to ensure security and minimize wait 

times, and (2) employing multiple monitoring mechanisms for the 

sufficiency of the model’s outputs. However, Federal Security Directors 

(FSD)—the ranking TSA authorities responsible for leading and coordinating 

security activities at airports—and our own analysis identified concerns with 

some of the fiscal year 2006 model assumptions. Although TSA officials said 

they plan an annual review of select assumptions and based changes for 

fiscal year 2007 on such a review of selected fiscal year 2006 assumptions, 

TSA does not have a mechanism for prioritizing its review and for assuring

that all assumptions are periodically validated to help ensure that they 

reflect operating conditions. Without periodic validation, TSA risks basing its 

allocations on assumptions that do not reflect operating conditions. For 

example, TSA acknowledged that it had not assessed the assumption that its 

method of calculating screening demand provides sufficient surplus staff to 

account for time away from screening for leave, training and operational 

support. Some FSDs told GAO their allocations did not include sufficient 

surplus in fiscal year 2006. Moreover, although TSA officials stated that the 

fiscal year 2007 model will include an allowance for time spent on 

operational support duties, TSA has not determined under what 

circumstances it is appropriate to use TSOs to perform operational support 

functions or provided FSDs with guidance on when TSOs can be used this

way. Without establishing such guidance, FSDs may over rely on TSOs to 

perform operational support functions. 

TSA has vested its FSDs with responsibility for managing their TSO 

allocations in light of local circumstances and challenges. Nevertheless,

factors outside the model’s determination of overall staffing levels can affect 

scheduling effectiveness. For example, FSDs face scheduling challenges

including injuries, absenteeism, and time spent away from primary screening 

duties for training and operational support. Officials described initiatives 

underway to address some of these issues. However, it is too soon to assess 

the effectiveness of these initiatives. 

Annual TSO Allocation Process 

Simulated passenger 

and checked baggage 

flow and number of 

TSOs to satisfy 

estimated demands.

Number of TSOs

required at 

each checkpoint 

provided in

 5 minute

 increments for a

representative 

week.

Combines future 

flight schedule and 

historical data to 

project flight 

activity.

Optimal mix offull-time/ 

part-time TSOs to satisfy 

passenger/baggage 

demand during a

representative week, 

expressed as annual 

FTE allocation.

Data

Schedule

Profile of each airport

Staffing protocols

Assumptions regarding 

passenger and baggage 

processing. 

Data on airport Historical data 

on screening

demand

Simulation of 

future screening

demand

Optimized annual

allocations

Source: GAO analysis of TSA Staffing Allocation Model.

www.gao.gov/cgi-bin/getrpt?GAO-07-299.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact Brian Lepore at

(202) 512-4523, leporeb@gao.gov. 
Letter 1

Results in Brief 5

Background 9

TSA Relies on the Assumptions in Its Staffing Allocation Model, 

along with Mechanisms for Monitoring Them, to Help Ensure 

Sufficient TSO Staffing Levels, but Some Key Assumptions Do 

Not Reflect Operating Conditions 22 

TSA’s FSDs Are Responsible for Deploying TSO Allocations at their 

Airports, but Face Workforce and Other Challenges to Effective 

Deployment 42

Conclusions 58

Recommendations for Executive Action 59 

Agency Comments and Our Evaluation 59 

Appendix I Objectives, Scope, and Methodology 62 

Objectives 62

Scope and Methodology 62 

Data Reliability 68 

Appendix II Development and Description of TSA’s Staffing 

Allocation Model 69 

TSA’s Development of Its Staffing Allocation Model 69 

Staffing Allocation Model Components 70 

TSA’s Use of the Staffing Allocation Model 76 

Appendix III Comments from the Department of Homeland Security 78 

Appendix IV GAO Contact and Staff Acknowledgments 84 

Related GAO Products 85 

Tables 

Table 1: Examples of Differences in Screening Operations, at

Selected Airports We Visited, That Resulted in Differing 

TSO Allocations 25 

Contents 

Page i GAO-07-299 TSA Staffing Standards
Table 2: Average Peak Wait Times in Minutes, by Airport Category, 

Fiscal Years 2004-2006 27 

Table 3: Summary of Changes to the Staffing Allocation Model 

Implemented in Fiscal Year 2007 32 

Table 4: National Human Resource Initiatives by TSA for Its TSO 

Workforce 56

Table 5: Airports Visited during Design Phase 63 

Table 6: Airports Visited after the Design Phase 64 

Table 7: Staffing Allocation Model Assumptions for Fiscal Year 

2007 74 

Figures 

Figure 1: Commercial Airports by Airport Security Category, as of 

April 2006 10 

Figure 2: Passenger Checkpoint Screening Operation 12 

Figure 3: Checked Baggage Screening Operation 14 

Figure 4: TSA’s Use of the Staffing Allocation Model for Annual 

TSO Allocations and Scheduling of TSOs for Airports 17 

Figure 5: Total TSO Allocation, by Airport Category, for Fiscal

Years 2004 through 2007 20 

Figure 6: Percentage of Part-Time TSOs by Airport Category, Fiscal 

Years 2004 through 2006 36 

Figure 7: Percent of TSOs Used for Operational Support Functions, 

along with Average Hours Spent by Them on These 

Functions, by Airport Category for a 2-Week Period—

September 17, 2006, through September 30, 2006 39 

Figure 8: Airports’ On-Board Status, by Airport Category, 

Compared to TSO Staffing Allocation, in Full-TimeEquivalent TSOs, as of September 30, 2006 47 

Figure 9: Attrition Rates for Full-Time and Part-Time TSOs, Fiscal 

years 2004 to 2006 49 

Figure 10: Average Rate of TSO Absenteeism per 100 TSOs, by

Airport Category, for Fiscal Years 2004 - 2006 51 

Figure 11: TSA Workman’s Compensation Claims for Calendar 

Years 2004 - 2006, through June 2006 52 

Figure 12: TSO Overtime Hours as a Percentage of Total Hours 

Worked, by Airport Category, during Fiscal Years 2004 - 

2006 53

Page ii GAO-07-299 TSA Staffing Standards
Abbreviations 

ADASP Aviation Direct Access Screening Program 

BAO Bomb Appraisal Officer 

BDO Behavior Detection Officer 

DHS Department of Homeland Security 

DTW Detroit Metropolitan Wayne County Airport 

EDS Explosive Detection System 

ETD Explosive Trace Detection 

ETP Explosives Trace Portal

FSD Federal Security Director 

FTE full-time equivalent 

IND Indianapolis International Airport 

MCO Orlando International Airport 

N/A not available 

OSR on-screen resolution 

SNA John Wayne Airport 

SPOT Screening Passengers by Observation Technique

TSA Transportation Security Administration 

TSO Transportation Security Officer 

This is a work of the U.S. government and is not subject to copyright protection in the 

United States. It may be reproduced and distributed in its entirety without further 

permission from GAO. However, because this work may contain copyrighted images or 

other material, permission from the copyright holder may be necessary if you wish to 

reproduce this material separately. 

Page iii GAO-07-299 TSA Staffing Standards
United States Government Accountability Office

Washington, DC 20548 

 

February 28, 2007 

The Honorable Daniel K. Inouye 

Chairman 

The Honorable Ted Stevens 

Co-Chairman 

Committee on Commerce, Science, and Transportation 

United States Senate 

The Honorable James L. Oberstar 

Chairman 

The Honorable John Mica 

Ranking Minority Member 

Committee on Transportation and Infrastructure 

House of Representatives 

Over 600 million people travel by air each year in the United States, and 

the screening of airline passengers and their carry-on and checked 

baggage is vital to securing our transportation security system. The 

Aviation and Transportation Security Act, enacted in November 2001,

established the Transportation Security Administration (TSA) and 

significantly changed how passenger and checked baggage screening is 

conducted in the United States.1

 This act removed screening responsibility 

from air carriers and the contractors who conducted screening for them, 

and placed this responsibility with TSA. As a result, TSA hired and 

deployed about 55,000 federal passenger and baggage Transportation 

Security Officers (TSO)—formerly known as screeners—to more than 400 

airports nationwide based largely on the number of screeners that the air 

carrier contractors had employed. Since August 2002, however, TSA has 

 1

 Pub. L. No. 107-71, 115 Stat. 597 (2001). 

Page 1 GAO-07-299 TSA Staffing Standards
been statutorily prohibited from exceeding 45,000 full-time equivalent 

positions available for screening.2

TSA’s mission is to protect the nation’s transportation systems while also 

ensuring the free movement of people and commerce. To help accomplish 

its security mission, TSA has established standard operating procedures to 

ensure that every airline passenger and checked bag undergoes some level 

of scrutiny to help ensure that objects and devices that may threaten 

public safety are not taken onboard aircraft. Although, according to TSA 

officials, these security duties are the primary objective of its screening 

efforts, it also attempts to minimize the effect on the movement of people 

and commerce by seeking to keep wait times at airport checkpoints 

reasonable.

TSA has identified its most important asset in accomplishing its mission as 

the TSO workforce. TSA deploys TSOs to screen passengers and checked 

baggage at the nation’s more than 400 commercial airports. TSOs, for 

example, monitor passengers as they walk through metal detectors, 

examine carry-on items on X-ray machines, and conduct more thorough 

inspections of passengers selected for additional scrutiny at screening 

checkpoints. The rapid changes in procedures stemming from the alleged 

August 2006 terrorist plot to detonate liquid explosives onboard multiple 

commercial aircraft departing from the United Kingdom and bound for the 

United States highlights the challenge TSA faces in balancing security with 

customer service and the vital role TSOs play in ensuring the security of 

our commercial aviation system. 

The Intelligence Reform and Terrorism Prevention Act of 2004, enacted in

December 2004, required TSA to develop and submit to the Senate 

Committee on Commerce, Science, and Transportation, and the House of 

Representatives Committee on Transportation and Infrastructure, 

standards for determining the aviation security staffing for all airports at 

 2

Beginning in August 2002 and continuing through fiscal year 2003, Congress prohibited 

TSA from recruiting or hiring personnel that would cause it to exceed a staffing level of

45,000 full-time-permanent positions. See Pub. L. No. 107-206, 116 Stat. 820, 880 (2002); 

Pub. L. No. 108-7, 117 Stat. 11, 386 (2003). Since fiscal year 2004, Congress has specifically

prohibited TSA from recruiting or hiring personnel that would cause it to exceed a staffing 

level of 45,000 full-time equivalent screeners. See Pub L. No. 108-90, 117 Stat. 1137, 1142 

(2003); Pub. L. No. 108-334, 118 Stat. 1298, 1304 (2004); Pub. L. No. 109-90, 119 Stat. 2064, 

2070 (2005); and Pub. L. No. 109-295, 120 Stat. 1335, 1363 (2006). One full-time equivalent 

equals 1 work year or 2,080 non-overtime hours. 

Page 2 GAO-07-299 TSA Staffing Standards
which TSA provides or oversees screening services by March 2005.

3

 These 

standards are to provide the necessary levels of aviation security and 

ensure that the average aviation security related delay experienced by

passengers is minimized. TSA submitted these standards, which form the 

basis of TSA’s Staffing Allocation Model on June 22, 2005. The purpose of

this optimization model,4

 as identified by TSA, is to estimate the most 

efficient balance of TSOs needed to ensure security and minimize wait 

times. Models, in general, are expected to approximate the real world. 

These approximations must be validated to assure model users that their 

predictions are credible within the bounds of specific situations, 

environments, and circumstances. 

The Intelligence Reform and Terrorism Prevention Act also mandated that

we conduct an analysis of TSA’s staffing standards. In particular, the 

congressional committees to which TSA submitted the staffing standards 

were interested in how TSA is using the Staffing Allocation Model to 

identify the number of TSOs needed across the more than 400 commercial 

airports and how the model ensures that TSA has the right number of 

TSOs at the right checkpoints at the right times. 

This report addresses the following questions: (1) How does TSA ensure 

that its Staffing Allocation Model provides a sufficient number of TSOs to 

perform passenger and checked baggage screening at each airport and 

what challenges has it faced while implementing the model? (2) How does 

TSA deploy its TSO allocation and what factors affect the model’s 

effectiveness in helping TSA accomplish this deployment? 

To address our objectives, we reviewed TSA’s report to the specified 

congressional committees on its staffing standards and technical materials 

 3

Pub. L. No. 108-458, § 4023, 118 Stat. 3638, 3723-24 (2004). 

4

An optimization model is a decision-making tool that recommends an answer (the goal to 

be optimized) based on analyses of information (constraints and decision variables). It 

consists of three components: (1) the goal to be optimized, (2) constraints, and (3) decision 

variables. In the case of TSA's Staffing Allocation Model, the goal to be optimized is the 

minimum number of TSOs to perform the necessary security functions at each airport

within the stated wait time goal of 10 minutes. The constraints include passenger and 

baggage volume, and arrival distributions. The decision variables include the configuration 

of each airport (concourses, lanes, screening equipment, etc), staffing requirements, etc.

TSA officials can alter decision variables to allow the model’s outcome to meet the goal. 

For example, more screening lanes can be opened to meet demand and faster screening 

equipment could be installed. Decision variables have bounds within which the model must

operate; these include, for example, how many lanes currently exist that could be opened. 

Page 3 GAO-07-299 TSA Staffing Standards
detailing the staffing allocation model’s assumptions,5

 and analyzed 

relevant legislation. We analyzed screening performance and TSO 

workforce data, such as passenger wait times, TSO absenteeism rates, 

TSO attrition rates, TSO overtime usage, TSO injury rates, number of TSOs 

devoted to administrative duties, and the level of usage of part-time TSOs. 

We assessed the reliability of these data for fiscal years 2005 and 2006 and 

concluded that the data were sufficiently reliable for the purposes of this 

review. We also interviewed officials from various TSA headquarters 

offices to ascertain the methodology used in developing the Staffing 

Allocation Model. We reviewed TSA’s previous staffing model, examined 

methods used by TSA for allocating TSOs to the nation’s airports, and 

reviewed TSA’s approach to monitoring the performance of the Staffing 

Allocation Model and obtaining feedback from Federal Security 

Directors—the top ranking TSA authority responsible for security at each

of the nation’s commercial airports—on their staffing allocations. We 

visited 14 airports selected by nonprobability sampling during our review. 6

 

We visited 6 of the 14 airports during the design phase of our review based

on several factors including geographic location and airport category.7

 

After completing the design phase of our study, we visited eight additional

airports including two airports from each of categories X, I, II, and III. We 

selected the two airports in each category because they had a similar 

number of annual passenger boardings, yet had different TSO allocations

as determined by the Staffing Allocation Model. We visited each pair of 

airports in order to determine why the model treated seemingly similar 

airports differently. At all 14 airports we visited, we met with Federal 

Security Directors (FSD) and their staffs to discuss their views on how 

well the airport’s TSO staffing allocation takes into account the unique 

characteristics of the airport and the TSO workforce and to observe 

 5

In the context of models, the term assumption means any value in the model that is based 

on a belief or decision rather than on actual data. The term assumption is generally used 

with models because the components of a model are assumed to realistically represent

events that the model is trying to explain or predict. 

6

Nonprobability sampling is a method of sampling where observations are selected in a 

manner that is not completely random, usually using specific characteristics of the 

population as criteria. Results from nonprobability samples cannot be used to make

inferences about a population because in a nonprobability sample, some elements of the 

population being studied have no chance or an unknown chance of being selected as part

of the sample. 

7

TSA classifies the commercial airports in the United States into one of five security risk 

categories (X, I, II, III, and IV). In general, category X airports have the largest number of

passenger boardings, and category IV airports have the smallest. Categories X, I, II, and III

airports account for more than 90 percent of the nation’s air traffic. 

Page 4 GAO-07-299 TSA Staffing Standards
passenger and checked baggage screening operations. We also met with 

representatives from the airport governing authority and at least one of the 

larger airline operators, based on passenger enplanements,8

 to obtain their 

perspectives on TSA’s implementation of the Staffing Allocation Model 

and other relevant workforce issues. Because we selected a 

nonprobability sample of airports to visit, the information we obtained 

from interviews in our visits to different airports cannot be generalized to 

all Federal Security Directors, airport managers, and air carriers. We also 

met with representatives from aviation industry associations to obtain 

their perspectives on relevant TSA workforce issues. 

We conducted our work from January 2006 through January 2007 in 

accordance with generally accepted government auditing standards. More 

details about the scope and methodology of our work are presented in 

appendix I. 

TSA aims to ensure that its Staffing Allocation Model provides a sufficient 

number of TSOs to perform passenger and checked baggage screening by:

(1) building assumptions into its allocation model that are designed to 

calculate the necessary levels of TSOs to ensure security and minimize 

wait times, and (2) employing multiple monitoring mechanisms (both 

headquarters and field driven) for the sufficiency of the model’s outputs. 

However, TSA faces some challenges to effective implementation of the 

model, primarily in ensuring that the model’s key assumptions reflect 

operating conditions across airports. The model determines the annual 

TSO allocation for each airport by first considering the workload demands 

unique to each airport based on an estimate of each airport’s peak 

passenger volume. This input is then processed against certain TSA 

assumptions about screening passengers and checked baggage—including 

expected processing rates, required staffing for passenger lanes and 

baggage equipment based on standard operating procedures, and 

historical equipment alarm rates.9

 Among the model’s key assumptions is 

that establishing TSO allocations at a level adequate to respond to 

screening demand on a representative week during each airports’ busiest 

month should allow most passengers on most days to experience 10 

minutes or less wait time and should provide enough surplus staffing on 

Results in Brief 

 8

 Enplanements are the number of passengers who board a plane. 

9

 Alarm rates refer to the number of persons or bags per hour/day that set off an alarm in 

the screening device and consequently require additional screening. 

Page 5 GAO-07-299 TSA Staffing Standards
lower-volume days to sufficiently account for leave, training, and other 

nonscreening duties during less busy times.10 Another key assumption is 

that the appropriate ratio of full-time to part-time TSO staff, expressed in 

full-time equivalents, is 80 percent to 20 percent; which, in TSA’s view, will 

allow FSDs to schedule TSOs to respond to fluctuating passenger volumes 

by scheduling part-time TSOs to work only during peak periods—e.g., 

most business travelers fly in the early morning or late afternoon and are 

the biggest contributors to these peak volumes. To monitor the sufficiency

of the model’s allocation outputs, TSA has both field and headquartersdriven mechanisms in place. For example, TSA has established a process 

for FSDs to request revisions to the assumptions used for their individual 

airports. According to TSA officials, during the first 2 years of the 

implementation of the Staffing Allocation Model, TSA granted some, but 

not all, of FSDs’ requests to modify the assumptions used for their 

individual airports. In addition, TSA plans to conduct an annual review of

certain assumptions in the Staffing Allocation Model. Based on the review 

conducted in 2006, TSA made several changes to the assumptions in the 

staffing model for fiscal year 2007, including allowances for various forms 

of leave and training in addition to a variable part-time assumption for 

each airport. TSA headquarters officials responsible for the model stated 

that in deciding which assumptions to review in 2006—the first annual 

review of the model—they considered input they received from FSDs 

regarding operational conditions at their airports that may not be 

adequately reflected in the model, along with other data and events that 

may have a bearing on the validity of the assumptions. However, TSA does 

not have a mechanism, such as a documented plan, for selecting and 

prioritizing which assumptions to review each year and for assuring that 

all assumptions are periodically reviewed to help ensure that they are

current with and reflect actual operating conditions. Without a plan for 

periodically validating all of the assumptions, TSA is at risk of assumptions 

becoming outdated, which could result in TSO allocations that do not 

reflect operating conditions. TSA officials responsible for the staffing 

model acknowledged that while they had a general idea of how they plan

to approach future annual reviews of the model, a documented plan would 

help provide assurance that the assumptions are periodically reviewed and 

validated. Although at the airports we visited, FSDs reported that the 

 10Screening demand refers to the volume of passenger and nonpassenger traffic expected

to require screening at an airport’s checkpoint(s) within a specified time period. Screening 

demand does not include domestic passengers who board connecting flights at airports 

since they have already been screened at their airport of origin. Therefore, with regard to

passengers, screening demand only refers to those who are originating at each airport. 

Page 6 GAO-07-299 TSA Staffing Standards
model is a more accurate predictor of staffing needs than TSA’s prior 

staffing model, which took into account fewer factors that affect screening 

operations, the FSDs and our own analysis identified some assumptions 

used in the fiscal year 2006 staffing model that did not reflect operating 

conditions. For example, many airports did not achieve a 20 percent parttime TSO workforce in the first 2 years of the model’s implementation. 

TSA has addressed this problem in fiscal year 2007 by implementing a 

variable part-time goal based on each airport’s part-time to full-time TSO 

ratio. In addition, some FSDs we visited stated that demand assumptions 

(using a representative week of airports’ busiest months) did not 

sufficiently provide enough time for leave, training, and other operational 

support (nonscreening) duties. TSA officials acknowledged that they had

not performed analysis to determine the reliability of this assumption. 

Also, FSDs stated the model for fiscal year 2006 did not specifically 

account for time away from screening to perform operational support 

duties, such as payroll processing. Although TSA officials told us that they 

have included an allowance for operational support duties in the 2007 

Staffing Allocation Model, TSA has not determined under what 

circumstances it is appropriate to use TSOs to perform operational 

support functions or provided FSDs with guidance on when TSOs can be 

used this way. Without establishing such guidance, FSDs may over rely on

TSOs to perform operational support functions. Overreliance on TSO staff 

for operational support could undermine TSA’s investment in their 

specialized screening skills, reduce their on-the-job training opportunities, 

and constrain flexibility in scheduling them for the most efficient use of 

available resources. 

TSA has vested its FSDs with responsibility for deploying and managing to 

their TSO allocation in light of local circumstances, including those that 

might affect scheduling and pose challenges to most efficiently deploying 

their resource allocations. Specifically, FSDs are responsible for ensuring 

that the right number of TSOs are deployed to the right screening areas at

the right times to meet airport screening needs. These needs can vary 

widely throughout the day because some airports experience greater 

levels of air traffic at some times of the day as compared with other times. 

After receiving the annual staffing allocation from TSA headquarters, FSDs 

must prepare work schedules, which may include use of the Staffing 

Allocation Model’s optional scheduling tool, to deploy TSO staff to meet 

screening demand. However, FSDs we interviewed identified several 

challenges they faced in deploying their TSO workforce. These challenges

involve factors outside the model’s determination of overall TSO staffing 

levels and affect FSDs’ ability to effectively deploy their TSO staff 

regardless of their allocation. Specifically, FSDs cited difficulties in 

Page 7 GAO-07-299 TSA Staffing Standards
achieving a 20 percent part-time TSO workforce, which the model has 

identified as the optimal ratio for scheduling efficiency; recruiting and 

retaining sufficient TSOs (both full-time and part-time) to reach their full 

allocations as determined by the model; staffing checkpoints appropriately 

given that some TSOs are unavailable due to absenteeism and injuries; and 

managing competing demands on TSOs’ time, particularly with regard to

operational support functions sometimes performed by TSOs and TSO 

training requirements. FSDs also had to manage around physical 

infrastructure limitations at some airports, such as lack of room for 

additional lanes or baggage check areas despite demand levels that would 

justify such added capacity. TSA headquarters officials and FSDs we 

interviewed reported having several efforts underway to help address 

challenges they face in deploying the TSO workforce. For example, TSA 

headquarters has several nationwide efforts underway to address hiring 

and retention of TSO staff (including part-time), absenteeism, injuries, and 

competing demands on TSO time. TSA officials at individual airports we 

visited are also working to address these challenges. For example, 6 of the 

14 FSDs we interviewed said they implemented local initiatives, such as 

injury prevention committees and safe lifting demonstrations to help 

reduce the number of on-the-job injuries. Given that many of TSA’s 

workforce initiatives were only recently implemented or are in the 

planning stages, we could not assess the extent to which these initiatives 

achieved the intended results. TSA human capital officials told us that they

plan to evaluate the effects of their workforce initiatives and use the 

results of the evaluations to make any needed changes to their approach.

To assist TSA in its efforts to identify TSO staffing levels that reasonably 

reflect the operating conditions at individual airports and to help ensure 

that TSOs are effectively utilized, we are recommending that TSA 

(1) establish a formal, documented plan for reviewing all of the 

assumptions in the Staffing Allocation Model on a periodic basis to ensure 

that the assumptions result in TSO staffing allocations that accurately 

reflect operating conditions that may change over time; and (2) establish a 

policy for when TSOs can be used to provide operational support. 

We provided a draft copy of this report to DHS for review. DHS, in its 

written comments, concurred with our findings and recommendations, 

and stated that the findings and recommendations are constructive and 

useful. DHS described some actions TSA has initiated to implement these 

recommendations, including working to develop a policy that would 

define when TSOs might be used to provide operational support. The full 

text of DHS’s comments, as well as additional comments from TSA 

Page 8 GAO-07-299 TSA Staffing Standards
regarding the agency’s workforce management initiatives, is included in 

appendix III. 

There are more than 400 airports in the United States at which TSA 

provides or oversees passenger and checked baggage screening. These 

airports, often referred to as the nation’s “commercial” airports, each 

contain one or more passenger screening checkpoints, and each 

checkpoint is composed of one or more screening lanes.11 In addition, 

airports have one or more baggage screening areas, either in airport 

lobbies or baggage makeup areas where baggage is sorted for loading onto 

aircraft. As of October 31, 2006, the nation’s commercial airports 

contained a total of 761 checkpoints and 2,002 screening lanes at which 

passengers are screened. These airports can vary dramatically, not just in 

terms of passenger and flight volume, but in other characteristics, 

including physical size and layout. Figure 1 identifies the number of 

commercial airports by airport security category, as of April 2006. 

Background 

Our Nation’s Commercial 

Airports 

 11 According to TSA, the total number of commercial airports regulated for security in the 

United States varies depending on various factors such as the type and level of commercial 

operations that an aircraft operator conducts at that particular airport, the time of year or 

season where a particular airport is located, and the economic stability of that airport’s 

region. 

Page 9 GAO-07-299 TSA Staffing Standards
Figure 1: Commercial Airports by Airport Security Category, as of April 2006 

6%

12.2%

16.3%

Source: GAO analysis of TSA data.

26.5%

39%

27

55

73

119

175

Total : 449

Number

of airports

X

I

II

III

IV

Airport

category

Federal Security Directors (FSD) are the ranking TSA authorities 

responsible for leading and coordinating TSA security activities at the 

nation’s commercial airports. TSA had 122 FSD positions at commercial 

airports nationwide, as of October 2006. Although an FSD is responsible 

for security at every commercial airport, not every airport has an FSD 

dedicated solely to that airport. Most category X airports have an FSD 

responsible for that airport alone. Other smaller airports are arranged in a 

“hub and spoke” configuration, in which an FSD is located at or near a hub 

airport but also has responsibility over one or more spoke airports of the 

same or smaller size. 

Performance of Screening 

Functions at Commercial 

Airports 

Passenger screening is a process by which authorized personnel inspect 

individuals and property to deter and prevent the carriage of any 

unauthorized explosive, incendiary, weapon, or other dangerous item 

aboard an aircraft or into a sterile area.12 Passenger screening personnel 

 12 TSOs conduct passenger and baggage screening at all but six commercial airports. These 

six airports have opted out of federal screening and, instead, utilize screeners employed by 

private screening companies under contract to TSA to perform these services. 

Page 10 GAO-07-299 TSA Staffing Standards
must inspect individuals for prohibited items at designated screening 

locations.13 There are four screening functions at passenger screening 

checkpoints. As shown in figure 2, the four passenger screening functions

are: 

• X-ray screening of property, 

• walk-through metal detector screening of individuals, 

• hand-wand or pat-down screening of individuals, and 

• physical search of property and trace detection for explosives.

Typically, passengers are only subjected to X-ray screening of their carryon items and screening by the walk through metal detector. Passengers 

who set off the alarm on the X-ray machine or the walk through metal 

detector or who are designated as selectees—that is, passengers selected 

by a computer-assisted passenger prescreening system14 or another TSAapproved process to receive additional screening—are screened by handwand or pat-down and have their carry-on items screened for explosives 

traces, or they are physically searched. 

 13 Sterile areas are located within the terminal where passengers are provided access to 

boarding aircraft. Access to these areas is controlled by screening personnel at checkpoints

where they conduct physical screening of individuals and their accessible property for 

weapons, explosives, and other prohibited items. Screeners must deny passage beyond the 

screening location (into the sterile area) to any individual or property that has not been

screened or inspected in accordance with law, regulation, and passenger screening 

standard operating procedures. 

14 The computer-assisted passenger prescreening system is a system that, based on 

information obtained from airline reservation systems, identifies passengers that may pose 

a higher risk to aviation security. These higher-risk passengers and their baggage are 

subject to additional screening.

Page 11 GAO-07-299 TSA Staffing Standards
Figure 2: Passenger Checkpoint Screening Operation

Behavior Detection Officer (BDO)a

Manual or ETD searchesc

Video surveillance

Source: GAO and Nova Development Corporation.

Passenger screening functions

X-ray

X-ray

X-ray screening

Physical barriers

(walls/partitions)

Walk-though

metal detector screening

Hand-wand or pat-downb

Note: Bomb Appraisal Officers are available to respond to unresolved alarms at the checkpoint that 

involve possible explosive devices. The Bomb Appraisal Officer may contact appropriate law 

enforcement or Bomb Squad officials if review indicates possible or imminent danger, in which case 

the officer ensures that the security checkpoint is cleared. The officer approves reopening of security

lane(s) if no threat is posed. 

a

Behavior Detection Officers are TSOs specially trained to detect suspicious behavior in individuals 

approaching the checkpoint. Should the BDO observe such behavior, he or she may refer the 

individual for individual screening or to a law enforcement officer. 

b

The hand-wand or pat-down is conducted if a passenger is identified or randomly selected for 

additional screening because he or she met certain criteria or alarmed the walk-through metal 

detector. 

c

Manual or ETD searches of accessible property occur if the passenger is identified or randomly 

selected for additional screening or if the TSO identified a potential prohibited item on X-ray. 

Checked baggage screening is a process by which authorized security 

screening personnel inspect checked baggage to deter, detect, and prevent

the carriage of any unauthorized explosive, incendiary, or weapon 

Page 12 GAO-07-299 TSA Staffing Standards
onboard an aircraft. As shown in figure 3, checked baggage screening is 

accomplished through the use of explosive detection systems15 or 

explosive trace detection systems,16 and through the use of alternative 

means, such as manual searches, canine teams, and positive passenger bag 

match,17 when the explosive detection or explosive trace detection systems 

are unavailable. 

 15 Explosive detection systems use probing radiation to examine objects inside baggage and 

identify the characteristic signatures of threat explosives. This equipment operates in an

automated mode. 

16 Explosive trace detection works by detecting vapors and residues of explosives. Human 

operators collect samples by rubbing bags with swabs, which are chemically analyzed to

identify any traces of explosive materials. 

17 Positive passenger bag match requires that passengers be on the same aircraft as their 

checked baggage. According to TSA, this procedure is rarely used. 

Page 13 GAO-07-299 TSA Staffing Standards
Figure 3: Checked Baggage Screening Operation

Manual searches

TSA certified K-9 teams

Source: GAO and Nova Development Corporation.

Baggage screening functions

Explosive detection

system (EDS)

Explosive trace

detection (ETD)

Explosive detection

or

Positive passenger

bag match

Primary screening Alternative screening means

History of TSO Staffing 

Levels and Staffing Models 

The Aviation and Transportation Security Act mandated that TSA assume 

responsibility for passenger and checked baggage screening at the nation’s 

airports using federal employees within 1 year of enactment.18 By 

November 2002, TSA had fully deployed a federal passenger and checked

baggage TSO workforce of about 55,000 full-time equivalents to the 

nation’s commercial airports. This level of TSOs needed to conduct 

passenger and checked baggage screening was identified by a consultant, 

relying largely on the number of private sector screeners that had been in 

place prior to TSA. Subsequently, TSA decided to develop a staffing model

 18 See Pub. L. No. 107-71, § 110(b)-(c), 115 Stat. at 614-16 (enacted on November 19, 2001). 

See also 49 U.S.C. § 44901(a). 

Page 14 GAO-07-299 TSA Staffing Standards
to more effectively determine the appropriate number of TSOs needed at 

the nation’s airports. TSA developed a demand driven model—a model 

based on flight schedules, connecting flight data, passenger loads,19

passenger arrival distribution curves,

20 and number of passenger bags 

along with throughput rates for processing the passengers and bags—in an 

effort to make screening operations more efficient.21 This model identified 

a TSO staffing level of 49,600 full-time equivalents based, in part, on the 

need for 5.5 TSOs per passenger screening lane. The DHS Appropriations 

Act, 2004, enacted in October 2003, however, imposed a 45,000 full-timeequivalent cap specific to the number of TSOs.22

In May 2003, TSA set out to develop a tool to better define aviation 

security staffing requirements at airports nationwide by accounting for 

changes in screening technology, operating conditions, and airline 

operations. The result of this effort is the Staffing Allocation Model—an 

optimization model that seeks, within certain TSA constraints,23 to 

estimate the most efficient balance of TSOs needed to ensure security and 

minimize wait times. 

As shown in figure 4, TSA uses the staffing allocation model to generate 

(1) an annual full-time-equivalent total for each airport, known as an 

“annual allocation run,” and (2) TSO work schedules throughout the 

course of the year, known as a “production, or scheduling, run.” To 

 19According to TSA, historical data on the number of passengers on each flight are known 

as “load factors” or passenger loads. Using historic data on passenger load factors, TSA

estimated the number of passengers to be screened at each airport. 

20According to TSA, the rate at which passengers arrive at security checkpoints in 

anticipation of specific flights, is known as “passenger arrival distribution curves.” These 

distribution curves show, based on historical data, how many passengers will arrive for the

flights at different intervals of time prior to the flight. 

21We were limited in the extent to which we could assess TSA’s prior staffing models 

because the TSA personnel responsible for overseeing the development of the earlier 

model are no longer employed by TSA and limited documentation on the models was

available. 

22According to TSA, private screeners do not count against the 45,000 full-time-equivalent 

ceiling. TSA currently contracts private screening companies to perform passenger and 

checked baggage screening at six commercial airports as part of its Screening Partnership 

Program, which allows commercial airports to opt to use private screeners in lieu of TSOs. 

TSA provides private screening companies with their full-time-equivalent levels based on 

the levels identified by the staffing allocation model. See GAO-06-166. 

23Some of the constraints include the number of checkpoints and screening lanes at an

airport, and the distribution of arriving and departing flights throughout the day. 

Page 15 GAO-07-299 TSA Staffing Standards
determine the annual full-time-equivalent total for each airport, FSDs must 

first provide input to the model on their airports’ passenger and checked 

baggage screening configuration. FSDs also provide input to the model on

their airports’ busiest month for screening demand based on originating 

passenger load factors. This “peak month” determination forms the basis 

of one of the model’s key operating parameters used to compute each 

airport’s full-time-equivalent staffing allocation. Specifically, for 

determination of an airport’s annual full-time equivalent level, the model 

assumes a screening demand based on the average demand day during the 

airport’s peak month. This assumption is linked to TSA’s 10-minute wait 

time goal for processing passengers and baggage through security. 

According to TSA officials, the use of the average peak demand day is 

intended to ensure that, on an annual basis, 85 percent or more of the total

passengers screened in U.S. airports will not have to wait more than 10 

minutes to be screened. Once the peak month is selected for each airport, 

TSA performs the annual allocation run on a representative week within 

the peak month. 

Page 16 GAO-07-299 TSA Staffing Standards
Figure 4: TSA’s Use of the Staffing Allocation Model for Annual TSO Allocations and Scheduling of TSOs for Airports

Simulated flow of 

passenger and checked 

baggage through 

checkpoints and estimated 

number of TSOs at 

checkpoints to satisfy 

estimated demands.

Number of TSOs

required at each 

checkpoint provided 

in 5 minute 

increments for a

representative 

week.

Combines future flight 

schedule data from Official 

Airlines Guide with 

historical data on 

passengers to be screened 

from the Bureau of 

Transportation Statistics to 

provide projected flight 

activity for staffing model.

Optimal mix of full-time 

and part-time TSOs

to satisfy passenger/

baggage demand during a

representative week, 

converted into an FTE level 

within which the airport 

must operate for the entire 

year (annual allocation).

Data

Data

Schedule

Using input on number of TSOs at 

checkpoints, determines optimal mix of 

full-time and part-time TSOs to satisfy 

demand, which can be used to prepare a

detailed TSO work schedule.

Creation of detailed work 

schedulea

Schedule

Simulation of screening

demand

Based on updated data, simulates flow of 

passenger and checked baggage through 

airport and determines number of TSOs

required at each passenger checkpoint and 

baggage zone in 5 minute increments for the 

upcoming week. 

FSDs update flight schedules

and passenger loads from data

provided by air carriers on an 

ongoing basis throughout the 

year.

Updated demand data

Schedule

Profile of each airport 

Number of concourses/

gates, type and quantity of 

screening equipment.

Staffing protocols

TSOs/lane/equipment

Assumptions regarding

passenger and baggage 

processing

20% part-time for some airports, 

85th percentile demand day, 

equipment alarm rates, 

passenger baggage throughput, 

10 minute maximum wait time, 

among others.

Data on airport

Annual TSO allocation process

Scheduling runs throughout the year

Historical data on 

screening demand

Simulation of future 

screening demand

Optimized annual

allocations

Source: GAO, based on discussions with TSA officials.

a

Use of the model’s scheduling component is optional, and some FSD offices create detailed work 

schedules using other methods. 

Page 17 GAO-07-299 TSA Staffing Standards
After receiving and reviewing the inputs and assumptions for each airport, 

TSA runs the Staffing Allocation Model to determine each airport’s fulltime equivalent level for the upcoming year.24 During the run, the model 

takes each airport’s configuration and peak month screening demand 

input, combines it with the assumptions regarding baggage and passenger 

processing, and uses these factors to simulate the flow of passengers and 

baggage through an airport’s screening areas to provide work force 

requirements. Then it calculates the total number of TSOs required 

(expressed in full-time equivalents) for the year based on the results of 

running the model for the representative week of the peak month. This 

representative week FTE level is used to calculate the annual FTE 

estimate for the airport. 

After receiving their annual full-time-equivalent allocation, TSA staff at 

individual airports may periodically run the model throughout the year. As 

shown in figure 4, during these “scheduling” runs, FSD staff may use the

model’s optional scheduling tool to determine work schedules for TSO 

staff that will satisfy screening demand on a day-to-day basis.25 Similar to 

the annual allocation runs, TSA also inputs various historic data into the 

model during the scheduling runs. This input includes originating 

passenger load factors, estimates of number of bags per passenger, and 

passenger arrival distribution curves. 

In order to formulate TSO work schedules, the model monitors the 

passenger arrival patterns and recommends opening and closing lanes at

passenger checkpoints to accommodate the demand. The optional 

scheduling software recommends a mix of full-time and part-time TSOs to

satisfy the workforce requirements based on projected screening demand.

According to TSA officials responsible for the staffing allocation model, 

TSA first ran the Staffing Allocation Model in August 2004 for fiscal year 

2005. The model, which did not yet contain complete data on each airport, 

identified a TSO full-time-equivalent level of 47,865 across all airports. To 

reach the congressionally-mandated limit of 45,000 full-time-equivalent 

 24 TSA has established assumptions in the model that are largely uniform for all airports

while recognizing that slight variances may exist due to differing conditions among 

airports.

25 FSDs may choose to use the Staffing Allocation Model’s optional scheduling tool or an 

alternative method to prepare work schedules for their TSOs. In some cases, FSDs and 

their staff may choose to use the scheduling tool as is, modify its output, or use a 

scheduling method completely independent of the scheduling tool. 

Page 18 GAO-07-299 TSA Staffing Standards
TSOs, TSA applied a 7 percent reduction to the staffing levels identified by

the model across all airport categories. TSA officials stated that they 

subsequently questioned this approach given that smaller (category III and 

IV) airports have significantly fewer TSOs and, therefore, were more 

significantly impacted by the 7 percent reduction in full-time equivalent 

positions. 

According to TSA officials, because the Staffing Allocation Model was not 

centrally hosted26 and did not contain complete data, the model may have

over-estimated the required FTEs for fiscal year 2005. TSA determined that 

in August 2005, the Staffing Allocation Model contained complete and 

accurate data on each airport and the agency used it to identify TSO FTE 

allocations for each airport, and the output reflecting the total number of 

FTEs required—42,303—required no adjustment to fall within the 

congressionally-mandated limit of 45,000 TSO FTEs. According to TSA 

officials, when TSA ran the model, it did so without imposing a limitation 

on the maximum number of full-time-equivalent TSOs, including either the 

45,000 congressional limit or any budgetary limits. TSA informed FSDs of 

their TSO full-time-equivalent allocations in October 2005. Figure 6 shows 

the total TSO allocation, by airport category, for fiscal year 2004—the year 

prior to implementation of the staffing allocation model—through fiscal 

year 2007. 

 26According to TSA officials, “centrally hosted” refers to the fact that the Staffing Allocation

Model was not maintained on a database server accessible by both headquarters and field 

TSA personnel. Instead, in fiscal year 2005, TSA personnel at each airport ran the model on

standalone computers. Therefore, TSA headquarters’ oversight of inputs to the model by 

field personnel was not as effective prior to the advent of central hosting in fiscal year 

2006. 

Page 19 GAO-07-299 TSA Staffing Standards
Figure 5: Total TSO Allocation, by Airport Category, for Fiscal Years 2004 through 

2007 

1,194

68%

25%

1,802

4,321

13,114 24,070

1,145

1,873

4,352

12,616 24,223

1,161

1,823

4,447

12,524 22,348

Fiscal year 2004 Fiscal year 2005

Fiscal year 2006

Total: 44,501 Total: 44,209

1,195

4,540

1,696

12,334 21,829

Fiscal year 2007

Total: 42,303 Total: 41,594

Source: GAO analysis of TSA data.

X

I

II

III

IV

Airport categories

Note: The allocations in this figure reflect federal TSOs only and do not include private screeners 

employed at the 6 airports across the nation utilizing these personnel. 

Page 20 GAO-07-299 TSA Staffing Standards
FSDs, air carrier representatives, and airport operators we interviewed at 

the 14 airports we visited stated that TSA’s efforts to allocate a sufficient 

number of TSOs to screen passengers and checked baggage and minimize 

wait times have improved over the years. These officials stated that 

passenger and checked baggage screening has become more efficient as 

TSA has matured and gained a better understanding of the airport 

operating environment, and frequent travelers have become more familiar 

with the screening process. 

TSA’s Use of the National 

Screening Force, Reserve 

TSO Full-Time 

Equivalents, and Private 

Screeners for Certain 

Screening Needs 

TSA sets aside TSO full-time equivalents for needs outside of those 

considered by the Staffing Allocation Model in the annual allocation run 

for all airports. In order to handle short-term extraordinary needs at 

airports, TSA has established the National Screening Force of 615 TSOs 

who can be sent to airports to augment local TSO staff during periods of 

unusually high passenger volume. In addition, certain airports may, during 

the course of the year, experience significant changes to their screening 

operations (e.g., arrival of a new airline, opening of a new terminal, etc.). 

For these airports, TSA established a reserve of 329 TSO full-time 

equivalents for fiscal year 2006 that can be used to augment the existing 

force. This allocation approach allowed TSA to stay within the 43,000 fulltime-equivalent TSO budgetary limit for fiscal year 2006—a staffing level 

that TSA’s Assistant Secretary stated is sufficient to provide passenger and 

checked baggage screening.27 

Lastly, TSA allows certain airports to hire private contract screeners in 

lieu of TSOs. Under the Screening Partnership Program,28 six airports have 

applied to TSA and received approval to hire private contract screener 

forces as of fiscal year 2006. Despite the fact that these airports do not use 

federal screeners, TSA still used the Staffing Allocation Model to 

 27Appropriations received by TSA in fiscal year 2006 were sufficient to employ up to 43,000

full-time equivalent TSOs.

28The Aviation and Transportation Security Act established TSA and assigned TSA with the

responsibility of building a federal workforce to conduct screening of airline passengers 

and their checked baggage. See 49 U.S.C. §§ 114(a), 44901(a). ATSA also required that TSA

allow commercial airports to apply to TSA to transition from a federal to a private screener

workforce. See § 44920. To support this effort, TSA created the Screening Partnership

Program to allow all commercial airports an opportunity to apply to TSA for permission to

use qualified private screening contractors and private screeners. There are currently 6

airports participating in the Screening Partnership Program, including Jackson Hole,

Kansas City International, Greater Rochester International, San Francisco International, 

Sioux Falls Regional, and Tupelo Regional. 

Page 21 GAO-07-299 TSA Staffing Standards
determine the full-time equivalent screening staff at each of these airports 

for fiscal year 2006. These staffing levels, as determined by the model, 

served as a limit on the number of private screeners that the private 

screening contractors could employ. According to TSA, the 1,702 total fulltime equivalent staffing allocation at these airports does not count against

TSA’s nationwide ceiling of 45,000 full-time equivalents for TSO staff. 

TSA aims to ensure that its Staffing Allocation Model provides a sufficient 

number of TSOs to perform passenger and checked baggage screening by:

(1) building assumptions into its allocation model that are designed to 

calculate the necessary levels of TSOs to ensure security and minimize 

wait times, and (2) employing multiple monitoring mechanisms for the 

sufficiency of the model’s outputs. TSA’s staffing allocation model 

determined the fiscal years 2005 and 2006 TSO staffing level for each 

airport based on built-in assumptions designed to ensure the necessary 

levels of security and to minimize wait times—such as assumptions 

regarding processing of passengers and baggage through security 

checkpoints and information about each airport’s baseline configuration—

e.g., physical infrastructure. During the first 2 years of the Staffing 

Allocation Model’s use, TSA established several mechanisms to monitor 

the sufficiency of the model’s outputs and make adjustments in key model 

assumptions that do not fully reflect operating conditions for some 

airports. For example, TSA established a process for FSDs to request 

revisions to the assumptions used for their individual airports. In fiscal 

year 2006, TSA granted some, but not all, requests. TSA headquarters also 

started an assessment to evaluate selected Staffing Allocation Model 

assumptions, an assessment it expects to perform annually, varying the 

assumptions it examines each year. However, TSA does not have a 

mechanism for selecting and prioritizing which assumptions to review 

each year and for assuring that all assumptions are periodically reviewed. 

Additionally, FSDs and our own analysis identified concerns with the 

appropriateness of some of the assumptions for the fiscal year 2006 model. 

For example, some FSDs stated that TSA’s method of calculating 

screening demand (the 85th percentile day) to also account for TSO 

absences from screening did not provide them with sufficient surplus 

staffing. In addition, the model assumed a ratio of 20 percent part time to 

80 percent full time (expressed in full-time equivalents), even in airports 

that have consistently been unable to achieve a 20 percent part-time TSO 

workforce; and the model had no mechanism to account for use of TSOs 

to perform operation support functions. 

TSA Relies on the 

Assumptions in Its 

Staffing Allocation 

Model, along with 

Mechanisms for 

Monitoring Them, to 

Help Ensure 

Sufficient TSO 

Staffing Levels, but 

Some Key 

Assumptions Do Not 

Reflect Operating 

Conditions 

Page 22 GAO-07-299 TSA Staffing Standards
TSA’s Staffing Allocation Model determined the fiscal years 2005 and 2006 

TSO staffing level for each airport using several built-in assumptions 

regarding security and wait times, in addition to data that reflect each 

airports’ baseline configuration—e.g., permanent infrastructure and type 

of screening equipment.

The key built-in assumptions are adjustable and designed to help ensure 

the necessary levels of security while minimizing wait times and include: 

• The minimum number of TSOs needed to staff each passenger 

screening checkpoint or baggage screening area based on the standard 

operating procedures for screening passengers and checked baggage 

and throughput rates for passenger and checked baggage screening 

equipment (see app. II).

TSA’s Staffing Allocation 

Model Seeks to Determine 

the Optimal TSO Staffing 

Levels for Each Airport, 

Relying on Assumptions 

that Are Designed to Help 

Ensure Necessary Levels 

of Security and to 

Minimize Passenger Wait 

Times

• A 10-minute maximum wait time for processing passengers and 

checked baggage.

29

• Originating passenger and baggage load factors by airport based on a 

representative week during each airport’s peak month (the 85th 

percentile assumption), which TSA expects will give FSDs some time 

during less busy periods to allow TSOs to obtain required training, 

perform operational support functions, and take annual or other forms 

of leave.30

• A desired ratio of 80 percent full-time to 20 percent part-time TSO staff, 

expressed as full time equivalents, at each category X, I, and II airport 

to allow for heavier staffing during busier periods (e.g., the hours when 

business travelers typically depart) and to minimize overstaffing during 

less busy periods, times during which part-time TSOs would not be 

scheduled to work. 

 29 The wait time (e.g., 10, 20, or 30 minutes) set in the model will influence the number of 

lanes and baggage equipment required; and, therefore, the TSO staffing required to process

85 percent of the annual passengers in less than the wait time that is set. 

30 TSA determines this assumption by selecting the month with the highest average 

passenger demand day (calculated by dividing total monthly passenger loads, reported by

airlines, by the number of days in the month) as the peak month. According to TSA, only 

about 7 percent of an airport’s days during the year will have greater passenger demand 

than this average peak demand day. TSA’s industrial engineers have determined that

running the model with a level of demand based on a representative week during this peak 

month will provide enough TSA staff to process 85 percent of passengers through security 

checkpoints in 10 minutes or less annually. 

Page 23 GAO-07-299 TSA Staffing Standards
• Nonpassenger throughput rate of 4 percent.31

• Rates at which screening equipment have historically signaled the 

possibility of a threat object and the consequent need for additional 

screening. 

The Staffing Allocation Model used these assumptions, along with other 

inputs such as each airport’s baseline configuration—e.g., the number and 

type of checkpoints, security lanes, baggage screening areas, and 

screening equipment at each airport—to determine TSO staffing 

allocations for the nation’s commercial airports for fiscal years 2005 and

2006. TSA officials stated that the assumptions used in the staffing 

allocation model and the other inputs collectively determine the TSO fulltime-equivalent allocation for each airport. For this reason, airports with 

similar screening demand but different checkpoint configurations and 

types of screening equipment may receive different allocations. For 

example, TSA officials identified two category I airports that have similar 

screening demand, yet one airport received almost 50 percent more fulltime equivalent TSOs in fiscal year 2006 due to the physical infrastructure 

differences at these airports. Specifically, one airport has one terminal 

building, with three concourses, which generally enables passengers to be 

efficiently routed through one checkpoint in that one terminal. In contrast, 

the other airport has two separate terminals that prevent passengers from 

being routed through common checkpoints. This airport’s separate 

terminals make sharing TSOs among the various checkpoints more 

challenging, creating a need for additional TSOs, thus the larger TSO 

allocation. Additionally, we visited category X and I airports with similar 

passenger volumes and differing TSO full-time-equivalent allocations for 

fiscal year 2006. According to TSA, in the case of the category X airports, 

while the passenger volumes for the two airports were similar—17.4 and 

16.5 million, respectively—the difference in the type of passengers and the 

type of baggage screening equipment resulted in one of these airports 

receiving 26 percent more full-time-equivalent TSOs. Table 1 provides a 

summary of the various factors that influenced full-time-equivalent TSO 

allocations for fiscal year 2006 at some of the airports we visited. 

 31Examples of non-passengers going through security checkpoints include flight crews and 

other airline employees, vendors at the airport, and other airport personnel. 

Page 24 GAO-07-299 TSA Staffing Standards
Table 1: Examples of Differences in Screening Operations, at Selected Airports We Visited, That Resulted in Differing TSO 

Allocations 

Airport 

Category Airports visited

FY 2006 model 

allocation

FY 2005 total 

enplanements

Differences in screening operations resulting in differing

allocation

X Detroit (DTW) 734 17,433,663

Orlando (MCO) 925 16,502,499

• Orlando has more originating passengers than Detroit, 

which results in more passengers to screen. Detroit has 

more connecting flights whose passengers have already 

been screened at their originating airport. 

• Detroit has a partial in-line baggage screening system, 

which requires fewer TSOs, and Orlando does not have 

an in-line system.a

I Indianapolis (IND) 292 4,211,461

Orange County

(SNA) 

217 4,791,100

• Indianapolis has more originating passengers than Orange 

County. Indianapolis is a mid-west airport with more 

connecting passengers that do not need to be screened. 

• Orange County has a full in-line baggage system, and 

Indianapolis has a partial in-line system serving only 3 

airlines. As a result, Orange County has a reduced need 

for baggage-screening TSOs.

a

• Orange County has 2 checkpoints in its terminal building 

that are close enough to one another to allow transferring 

of TSOs back and forth as screening demand dictates. 

This ease of sharing TSOs between the checkpoints 

results in a reduced number of TSOs than that called for 

by the model. In contrast, Indianapolis has 4 concourses 

with 3 checkpo

them, which the

ints and less ease of movement among 

model recognizes, thus requiring more

TSOs. 

Source: TSA and GAO observations at airports

Note: The fiscal year 2005 enplane . 

However, at the time we selected th est available 

data. 

a

An in-line baggage screening syste

existing baggage handling system, O 

staff) than stand-alone systems that are not integ baggage systems. In a partial inline system, the airport has some explosive detection systems integrated with the conveyor belts of 

the airport’s existing baggage handling system while others are in a stand-alone setup. An airport with 

a full in-line system has all of its explosive detection systems integrated with the baggage handling 

system. 

The Intelligence Reform and Terrorism Prevention Act of 2004 required 

TSA to develop staffing standards that provide for the necessary levels of 

security and minimize delays for passengers. According to TSA officials 

responsible for the Staffing Allocation Model, the model ensures that the 

staffing allocations provide for the necessary levels of security because the 

model is based on TSA’s standard operating procedures for screening 

passengers and their carry-on items and checked baggage and on the 

technology available at the passenger checkpoints and baggage screening 

areas. For example, the passenger checkpoint standard operating 

. 

ments data are only a rough indicator of actual screening demand

e airports to visit, enplanements data were the b

m integrates explosive detection systems with an airport’s 

requiring less human intervention (and, correspondingly, less TS

rated into existing 

Page 25 GAO-07-299 TSA Staffing Standards
procedures require that a minimum of one TSO be staffed for each of the

screening functions at a checkpoint. The staffing model includes an 

assumption (for larger airports) of at least 5.5 TSOs per screening lane—

which responds to the need for one TSO per function at every checkpoint

and includes a value for supervisors that typically oversee two lanes.32 In 

addition, the staffing model provides an allocation for each airport based, 

in part, on the screening technology at the airport. In addition, the model

includes assumptions on alarm rates for various types of passenger and

baggage screening equipment and determines the sufficient number of 

TSOs needed to resolve the alarms at the projected rate to be able to 

achieve the model’s wait time standard of 10 minutes for processing 

passengers and checked baggage.33

Regarding minimizing passenger delays, a key assumption in the staffing 

allocation model is that wait times for screening passengers and checked

baggage will not exceed 10 minutes when the model is set at a level 

referred to as the airport’s 85th percentile day, which TSA calculates by 

estimating screening demand at the level required for a representative 

week of each airport’s busiest month. TSA officials stated this assumption

is based on a goal that was established when TSA was first created within 

the Department of Tran

Department of Transporta

processed through passen

less—a standard consid

ensuring security while m

that they determined that on Model’s demand

level on the representat e

coincided with screening

officials told us that some 0

minutes at certain airports

that about 7 percent of an

the year are expected to e

 

sportation. Specifically, the Secretary of the 

tion established a goal that passengers be 

ger screening checkpoints in 10 minutes or 

ered appropriate to meet the dual needs of 

aintaining national mobility. TSA officials stated 

basing the Staffing Allocati

iv demand week of each airport’s peak month, 

85 percent of passengers within 10 minutes. TSA 

passengers will still have to wait longer than 1

at certain times due, at least in part, to the fact

airport’s travel days (about 25-30 days) during 

xceed the 85 percentile demand day.

32Based on their review of selected model assumptions, TSA has changed the number of

TSOs, per lane, for fiscal year 2007 from 5.5 to 4.25 (at category X, I, and II airports). 

33We currently have an ongoing review of the Department of Homeland Security’s and

TSA’s efforts to research, develop, and deploy airport screening operations. As part of this

review, we are determining the extent to which DHS and TSA have deployed technologies 

to mitigate terrorist threats effectively at airport passenger checkpoints while ensuring the 

efficient movement of passengers. We expect to report our results in August 2007. 

Page 26 GAO-07-299 TSA Staffing Standards
As shown in table 2, TSA data for fiscal years 2004 through 2006 show that 

the nation’s smaller airports (categories II, III, and IV) had shorter average 

wait times than the standard, overall, with a wait time during peak periods 

averaging less than 10 minutes, although wait times exceeded this level at 

certain airports on certain days.34 Average peak wait times at the nation’s 

larger airports (category X and I) generally exceeded the wait time 

standard, overall, although wait times were less than 10 minutes at certain

airports on certain days. According to TSA headquarters officials, if 

airports are consistently exceeding the 10 minute wait time goal, it is the 

responsibility of the Area Directors to reach out to the FSDs at those 

airports in an effort to determine whether the root cause relates to 

staffing, equipment, capacity, or some other issue and to take appropriate 

remedial action.35

Table 2: Average Peak Wait Times in Minutes, by Airport Category, Fiscal Years 2004-2006 

Average peak wait times in minutes 

Fiscal year All categories Category X Category I Category II Category III Category IV

FY04 9.4 13.0 11.8 8.5 9.1 8.6

FY05 8.9 12.0 11.2 8.3 8.7 8.2

FY06 8.2 12.6 10.4 7.7 8.0 7.2

Source: TSA. 

TSA officials cited capacity issues as a factor that contributed to category 

X airports generally exceeding the 10-minute wait time goal during peak 

periods, as shown in table 2. These airports have higher screening 

demand than smaller airports and sometimes lack the capacity, with 

regard to space available for additional passenger lanes and baggage 

 34 TSA is to collect wait time data every 30 minutes during peak hours (e.g., weekdays 

between 5:00 am-8:00 am and 3:00 pm-7:00 pm and Sundays between 4:00-9:00 pm) and 

every hour during non-peak periods of time. During each data collection period, a TSO is to 

stamp wait time cards with the current time, provide the cards to the last three passengers

d the last four passengers during peak periods. The

ay, a supervisory TSO is to collect the wait time cards from his or her checkpoint

in line during off-peak periods an

passengers are to give the cards to a TSO once they reach the front of the line and are 

directed to a lane for screening. The TSO is to record the time on the card. At the end of

each d

and enter the wait time data into the Performance Management Information System. 

35FSDs report to one of three Area Directors, based on their geographic regions, on

administrative matters. The Area Directors oversee transportation security at airports and

in other modes of transportation for the East Coast, Central, and Western regions, 

respectively. 

Page 27 GAO-07-299 TSA Staffing Standards
screening areas, to process passengers and baggage quickly enough to 

r 

at

O

enger

,

ve

The reviews are used to help improve 

the design of passenger and baggage checkpoints, evaluate staffing and 

that

n

can

ntrol,

ns,

 

have lower wait times. Smaller airports are more likely to have a numbe

of passenger lanes and baggage screening areas that are more 

commensurate with their screening demand than some larger airports th

have higher screening demand. 

TSA has four mechanisms in place to monitor the sufficiency of the TS

allocations. First, at individual airports, FSDs and the industrial engineers 

assigned to their airports are responsible for monitoring their pass

and checked baggage screening operations to ensure that the staffing 

allocation model’s inputs are reliable.36 A process currently exists to 

enable FSDs to request revisions to the assumptions used for their 

individual airports when they believe that a model assumption is 

unrealistic. As part of this process, FSDs are to submit empirical data to 

support requests to alter assumptions. Based on TSA’s review of the data, 

TSA may send an “optimization team” to the airport in an effort to identify

the cause of the staffing problem.37 Optimization teams are composed of

experts in passenger and baggage screening operations and procedures

the staffing allocation model, and TSO scheduling. These teams obser

screening operations and seek to maximize efficiencies by applying 

practices learned at other airports.

scheduling practices, determine compliance with the standard operating 

procedures, validate the TSO staffing model at the airport, and make 

adjustments to model assumptions, if necessary. TSA officials stated

they are formalizing a process for systematically collecting information o

best practices identified by optimization teams so that this information

be disseminated across airports. TSA’s solicitation of input from FSDs 

regarding changes that need to be made to the assumptions that guide

their TSO allocations is consistent with our standards for internal co

which call for management to ensure effective internal communicatio

36 TSA employs industrial engineers and assigns them to airports throughout the country

based on the geographic region. Each of the industrial engineers is assigned to TSA 

TSA Has Four Mechanisms 

in Place to Monitor the 

Sufficiency of Its TSO 

Allocations and Is 

Formalizing Its Process for 

Revising the Model’s 

Assumptions 

headquarters and reports to one of TSA’s three Area Directors. These engineers are

responsible for assisting and monitoring airports in their use of the Staffing Allocation

Model. 

37According to TSA officials, an optimization team is not sent to an airport in response to

every FSD request for a revision to an assumption for their airport. For example, if TSA

determines that it is readily apparent from the request that a change is not needed, TSA

would not send an optimization team to visit the airport. 

Page 28 GAO-07-299 TSA Staffing Standards
for example, by establishing mechanisms for employees to recommend 

improvements in operations.38

During the first 2 years of the implementation of the Staffing Allocation 

Model, TSA granted some, but not all, of FSDs’ requests to modify the 

assumptions used for their individual airports. TSA provided several 

examples of these requests and the final outcome. For example, an FSD 

requested a change to passenger screening throughput rates at some of the

passenger lanes in the international terminal due to the amount and type

TSOs,

 its 

tage

ters

ughput was primarily occurring during off-peak periods 

and would not have changed the model’s results for that airport. 

d not document all the 

requests that they received from FSDs, potentially limiting the 

agency’s ability to learn from past circumstances. TSA officials 

acknowledged that it would be helpful to fully document the requests they 

receive from FSDs and the outcome of these requests to help ensure 

consistency in their decision making, to provide a basis for management 

and decision makers to review and evaluate the decision-making process 

for potential improvements, and to replicate successful practices when 

g

 

of carry-on items passengers tended to carry through this checkpoint. 

After reviewing the FSD’s request and sending an optimization team to 

assess the validity of the request, TSA changed the model’s assumption 

about the passenger throughput rate for this checkpoint from 200 to 165 

passengers per hour at these lanes. TSA officials told us that, in situations

like this, the model will recommend opening more lanes and adding

if deemed warranted, to offset a reduction in the number of passengers 

screened per hour. In another example, an FSD requested a change in

non-passenger—flight crew and airport employees—throughput rate 

based on data collected at the checkpoint that showed a higher percen

of nonpassenger throughput than the model assumes. TSA headquar

officials denied the request because the higher percentage of

nonpassenger thro

TSA headquarters officials told us that they di

previous

similar circumstances arise at other airports. Officials stated that TSA is

formalizing its process for revising assumptions based on airport-specific 

circumstances. In August 2006, TSA developed and distributed to FSDs a

draft standard form to use when requesting deviations from the Staffin

Allocation Model’s standard assumptions. The form, finalized as of 

t, 

ust

38GAO, Internal Control: Standards for Internal Control in the Federal Governmen

GAO/AIMD-00-21.3.1 (Washington, D.C.: November 1999); Internal Control: Internal 

Control Management and Evaluation Tool, GAO-01-1008G (Washington, D.C.: Aug

2001). 

Page 29 GAO-07-299 TSA Staffing Standards
January 2007, captures information such as the date of the request; the

airport for which the request is being made; the justification for the 

request; and approvals at various levels, such as the industrial engineer 

and TSA headquarters. A stated that FSDs were previously made aware 

of the draft form and provided instructions on using this form through 

various communication mechanisms, including written instructions 

provided to FSDs and FSD conferences held in September 2006. TSA is 

also developing a database to record and track the requests made by FSDs, 

decisions on whether to approve or deny requests, and the basis for the 

decisions. TSA officials stated that they expect the database to be 

completed by April 30, 2007. 

Regarding the second mechanism to monitor the sufficiency of the model’s 

outputs, TSA headquarters officials said it is the responsibility of 

individual FSDs and the airports to 

ensure that the staffing allocation model reflects the configuration of and 

operating conditions at their airports. Therefore, TSA officials stated that,

just prior to the model’s annual allocation run for fiscal year 2006, they 

system ically solicited e industrial engineers assigned to th

more than 400 commercial airports to determine whether the model 

contains correct information regarding the configuration of each airport.39

TSA expects this process to occur annually in order to help ensure the 

the data inputs. 

alies 

an airport with consistently high wait 

mes (generally greater than 40 minutes during peak periods) may prompt 

uch a visit. During the visits, the optimization teams perform analyses 

(with the assistance of the staffing allocation model) to determine the 

 

TS

industrial engineers assigned to their 

at input from th e

reliability of 

As a third mechanism to monitor the sufficiency of the model’s outputs, 

TSA headquarters officials stated that they continually monitor 

performance data reported by individual airports to identify any anom

that may require further investigation such as high wait times over an

extended period of time, lower than expected throughput at passenger

lanes, high overtime rates (in excess of 4 percent), and airports with 

onboard TSO staff consistently below their staffing allocation. In some 

cases, anomalies identified by TSA may result in an optimization team visit

to an airport in an effort to determine their cause. For example, TSA 

headquarters officials stated that

ti

s

39 TSA assigns industrial engineers to assist these airports with their use of the staffing 

model based on the region of the country where they are located. However, TSA does not 

have sufficient levels of industrial engineers to locate one at each of these airports. As a 

result, a single industrial engineer may be responsible for assisting multiple airports.

Page 30 GAO-07-299 TSA Staffing Standards
causes of the problems the airport is having and suggest to the local FSD 

ways to increase efficiency in the passenger and baggage screening 

operations to overcome the problems. In some cases, the optimization 

team may conclude that a change to the Staffing Allocation Model’s 

baseline assumptions for the airport is necessary. For example, the ai

may have lower throughput rates at some of its passenger or baggag

screening areas than the Staffing Allocation Model assumes, due t

different types of screening equipment or the physical layout of the airpor

security checkpoints. 

Finally, according to TSA officials, in September 2006, TSA completed its

first annual review of certain assumptions in the Staffing Allocation Mode

This review included an assessment of whether the assumptions under 

review are still realistic, including assumptions related to screening 

procedures, technology, screening throughput, and nonpassenger alarm 

rates; and whether adjustments to the model are needed to make the full

time-equivalent allocation reflect actual operating conditions at airports. 

As a result, as shown in table 3, TSA has changed some assumptions a

added others to more realistically reflect actual operating conditions.

rport

e

o

t 

l.

-

nd

ear 

 

40 For

example, TSA headquarters officials responsible for the model stated the 

fiscal year 2007 model will provide 4.25 TSOs per passenger checkpoint 

screening lane rather than the 5.5 TSOs per lane provided in the fiscal y

2006 model—a change TSA officials attributed to the model directly 

accounting for collateral duties performed by TSOs, TSO time paid but not

worked,41 and TSO training requirements. 

 

e model held conferences with 

preparing TSO work schedules to help ensure that they 

nd 

40According to TSA, as part of the process of reviewing the staffing allocation model 

assumptions, TSA headquarters officials responsible for th

FSD staff responsible for 

understood the model and the changes implemented in fiscal year 2007.

41 This time includes annual, sick, and military leave in addition to compensatory time a

injury time off. 

Page 31 GAO-07-299 TSA Staffing Standards
Table 3: Summary of Changes to the Staffing Allocation Model Implemented in Fiscal Year 2007

Fiscal year 2006 staffing allocation model Fiscal year 2007 staffing allocation model 

Security

category

checkpoint staffing set at 5.5 for 

X, I, and II airports.

Security checkpoint staffing set at 4.25 for 

category X, I, and II airports.

Staffing constants 

EDS machine staffing set at 3. EDS machine staffing set at 2.

TSO paid-not-worked hours 

(annual, sick, and military leave, 

comp time, and injury time off) 

Not directly accounted for Each airport has a 14.5 percent annual FTE

allowance for time paid not worked. 

Operational support functions Not directly accounted for Airports in categories X, I, and II have a 5 percent

collateral duties FTE credit. 

TSO training Not directly accounted for Each airport has a 2 percent annual FTE

allowance for training that cannot be completed 

during operational down times.

Part-time TSOs Set at 20

X, I, and fullpercent of total FTEs for all category II airports.

TSA has implemented a variable part-time goal 

based on each airport’s individual part-time to

time ratio. 

ETD mac

(dependi

internal/e

60, 90, o

hine baggage processing rates 

ng on type of equipment and 

xternal screening methodology) set at 

r 180 seconds). 

ETD baggage processing rates set at 55, 98, or 

238 seconds. 

CTX 250

90 bags per hour. 

0 EDS machine screening rate set at CTX2500 set at 115 bags per hour. 

CTX5500

per hour. 

EDS screening rate set at 160 bags CTX5500 EDS screening rate set at 200 bags per 

hour. 

CT80 machine added with processing rate of 80 

bags per hour.

Baggage/passenger screening 

equipment processing rates 

Explosives Trace Portal (ETP) machine added with 

processing rate of 175 passengers per hour.

Baggage arrival distributions Included 6 different baggage distributions. Number of baggage distributions reduced to 2. 

New security initiatives Added line item allocation for SPOT,

a

 BAO,band

ADASPc

 security initiatives. 

Source: TSA.

a

TSA’s Screening Passengers by Observation Technique program is designed to detect individuals 

who exhibit behavior that indicates they may be a threat to aviation and/or transportation security. 

b

TSA’s Bomb Appraisal Officer initiative designates TSOs to receive specialized training in th

detection of improvised explosive devices and apply this knowledge at security checkpoints. 

e

ng for

dia.

in

y

c

TSA’s Aviation Direct Access Screening Program involves TSOs performing security screeni

explosives, incendiaries, weapons, and other prohibited items or improper airport identification me

This security screening will occur at direct access points to include secured areas, sterile areas, or 

aircraft operating areas outside of TSA’s security screening checkpoints. 

TSA officials responsible for the staffing allocation model stated that

deciding which assumptions to review for the fiscal year 2007 model, the

considered input they received from FSDs regarding operational 

Page 32 GAO-07-299 TSA Staffing Standards
conditions at their airports that may not be adequately reflected in

model, along with other data

the

and events that may have a bearing on the 

validity of the assumptions. However, TSA does not have a mechanism, 

ions are

of

ture annual reviews of the model, a 

documented plan would help provide assurance that the assumptions are 

g

ring

r

ear

irements. With respect to annual and sick leave, 5 

 

such as a documented plan, for selecting and prioritizing which 

assumptions to review each year and for assuring that all assumpt

periodically reviewed. Without a plan for periodically validating the 

assumptions, the agency is at risk of assumptions becoming outdated, 

which could result in TSO allocations that do not reflect actual operating 

conditions. Moreover, given the ongoing personnel changes in TSA, a 

documented plan would help provide future decision makers with 

information on which assumptions had historically been assessed and

which ones TSA planned to assess in the future. 42 TSA officials responsible

for the staffing model acknowledged that while they had a general idea

how they plan to approach fu

periodically reviewed and validated, and are current with actual operatin

conditions. 

FSDs we interviewed reported that the screening allocation model is a 

more accurate predictor of their overall staffing needs than previous 

models that took into account fewer factors affecting screening 

operations. However, these FSDs and our own analysis identified that 

some of the key assumptions used in the staffing allocation model, du

the first 2 years of its implementation, did not reflect actual operating 

conditions. Specifically, the FSDs identified five weaknesses in the model

for fiscal year 2006. 

First, 11 of the 14 FSDs identified concerns related to TSA’s basing its 

estimate of demand levels for the Staffing Allocation Model on a 

representative week of each airport’s peak screening demand month to

allow excess time for training, leave, and other factors not directly 

considered by the staffing allocation model. Regarding training, 9 of the 14 

FSDs expressed concern that the model did not specifically account fo

the training requirement of 3 hours per week averaged over a fiscal y

quarter. Three of these FSDs said they faced challenges in meeting the 

minimum training requ

Some Key Assumptions 

Used in the Fiscal Year 

2006 Staffing Allocation 

Model Did Not Reflect 

Operating Conditions at 

Individual Airports 

42Since its inception in November 2001, TSA has had multiple Assistant Secretaries 

(originally titled Under Secretaries of Transportation for Security). In addition, between 

January 2005 and August 2006, TSA issued seven press releases regarding senior-level 

personnel changes within the agency. 

Page 33 GAO-07-299 TSA Staffing Standards
of the 14 FSDs stated that in their view the model did not adequately 

account for this leave. Two FSDs stated that the use of the peak demand 

month to account for training and leave, though sound in principle, is 

particularly difficult for smaller airports because they do not have as

fluctuation between their peak period and their non-peak period, which 

leaves little cushion in the allocation to accommodate TSO absences from

screening duties such as training and annual leave. 

TSA headquarters officials stated that TSA determined that using the 85th

percentile day concept would more than account for training, leave, and 

other factors related to TSOs not being available for work because, 

according to TSA, on only about 7 percent of days do passenger volumes 

exceed it. Thus, according to TSA officials, the Staffing Allocation Mo

set at a high enough demand level to cover screening demand for most 

days during the year and allow for the extr

much

del is 

a time needed for necessary 

nonscreening time needed by TSOs such as training, leave, and other 

uties. TSA officials told us that they believe this method of calculating

demand provides the necessary level of security and, secondarily, reflects 

eir responsibility to be good financial stewards of taxpayer dollars, as 

using even higher volume days would result in higher costs and perhaps 

wer overall productivity. Regarding the need for an additional allowance 

for various forms of TSO leave needs, TSA had included an allowance, for 

for additional full-time 

nce) to cover annual,

l

headquarters o allowance in the 

Allocation M nt full-time 

wance) for trainin

operational down times. TSA sp ce to

provide additional assurance that TSOs complete the required training 

detecting improv

identified as the highest threat to co ty. 

TSA officials involved in developing the staffing model stated that they did 

not plan to assess the extent to which the representative week of 

screening demand during each airport’s peak month does, in fact, 

on

t of airline 

eckpoints.

d

th

lo

fiscal year 2007, in the Staffing Allocation Model

equivalents (14.5 percent full-time-equivalent allowa

sick, comp, injury, and military eave.

Additionally, TSA fficials have included an

fiscal 2007 Staffing odel (an additional 2 perce

equivalent allo g that cannot be completed during 

ecifically intended this allowan

each month on ised explosive devices—which TSA has 

mmercial aviation securi

represent actual screening demand for that week. However, officials 

acknowledged that such an assessment could help verify that, for 

purposes of the model’s annual allocation run, the resulting allocati

provides TSO staffing levels adequate to allow for 85 percen

passengers at the nation’s commercial airports to wait 10 minutes or less 

at security ch

Page 34 GAO-07-299 TSA Staffing Standards
Second, 7 of the 14 FSDs we interviewed stated that the goal of a 20 

me TSO workforc nt

TSOs, is not realistic. TSA data s

equivalent level at 13 airports we anged from 

0 percent part-time goa r 

mong

part-t

sit in some locations, TSO base pay that 

cal year 2002, the lack of benefits for part-time 

p ull-time

hen full-time positions become available. According to TSA, these 

d

difficult. As shown in figure 6, TSA d ta reflect that, nationwide, part-time 

levels of TSOs had not reached 2

implementation of the current staffing alloc

and 2006) with regard to the nat

re 6

2006, the nation’s 26 category X airpo

of about 9 percent part-time equ

number of part-time TSOs had increased in recent months. 

in matching the daily peak-load workflow at airports. Nonetheless, figure 

 

percent part-ti e, as measured by full-time-equivale

how that the part-time TSO full-timevisited,

43 as of July 2006, r

approximately 1 to 38 percent, w

that the 2

ith an average of 8 percent. FSDs stated

l for TSOs has been difficult to achieve fo

most airports because of, a

leading to competition for

coupled with a lack of mass tran

has not changed since fis

other things, economic conditions 

ime workers, remote airport locations 

TSOs, and the large number of

status w

art-time TSOs who convert to f

factors have made the hiring an retention of part-time TSOs particularly 

a

0 percent in the first 2 years of 

ation model (fiscal years 2005 

ion’s larger (category X, I, and II) 

airports.44 For example, figu also shows that in fiscal years 2005 and 

rts had a TSO workforce comprised 

ivalents. TSA officials stated that the 

TSA officials originally assumed that the 20 percent TSO part-time 

assumption provides the most efficient coverage for airports (especially 

those in categories X, I, and II) by enabling FSDs to have more flexibility 45

6 shows that, on average, only smaller airports (categories III and IV) came 

close to or exceeded the 20 percent part-time TSO workforce goal during

fiscal years 2004 through 2006. 

 

.

than

43 The 14th airport we visited, San Francisco, had private screeners instead of TSOs. 

44 This ratio of part-time to full-time is based on annualized full-time-equivalent data

According to TSA, an annualized number represents an estimate of the usage of FTEs over

the fiscal year assuming that the usage in a given pay period remains constant over all 

future pay periods. 

45 TSA officials stated that they conducted sensitivity analysis around various mixes of fulltime to part-time TSOs at category X airports and identified that no additional efficiency 

was gained at these airports with a full-time-equivalent level of part-time TSOs greater

about 20 percent. 

Page 35 GAO-07-299 TSA Staffing Standards
Figure 6: Percentage of Part-Time TSOs by Airport Category, Fiscal Years 2004 

through 2006 

Fiscal year

Percent

Total

X

I

II

III

IV

Source: GAO analysis of TSA data.

0 5 10 15 20 25 30 35

2006

2005

2004

31.15

18.48

15.18

11.50

9.00

12.15

29.32

11.39

7.72

11.54

13.53

18.44

11.01

10.19

8.07

11.77

20.99

25.52

Airport categories

Note: This figure includes data on federal TSOs only and not on private screeners employed at the 6 

airports across the nation utilizing these personnel. 

TSA has recognized that some airports cannot likely achieve a 20 percent

part-time FTE level and others (most likely smaller airports) may operate

more effectively with other levels of part-time TSO staff. As a result, for 

fiscal year 2007, TSA has modified this assumption to include a variable

Page 36 GAO-07-299 TSA Staffing Standards
part-time goal based on each airport’s historic part-time to full-time T

ratio. 

Third, 5 of the 14 FSDs stated that the staffing model does not appear to

consider new passenger screening procedures that may require addition

TSOs at the checkpoint. For example, one FSD stated that the model h

yet to incorporate the additional TSOs that will be required by TSA’s new

Screening Passengers by Observation Techniques program currently being

implemented at the nation’s airports.

SO

al

as

he

eening Program security initiatives. 

ngs

ning

l

e

e airports

have full in-line systems, while others have partial in-line systems that are 

ion in

g

ing

e

n.

ay should help ensure that the model adequately

reflects the actual operating conditions at the airport, which highlights the 

s

 

46 TSA headquarters officials 

acknowledged that changes to screening procedures could increase the 

number of TSOs needed at a checkpoint or, conversely, increase wait 

times at the checkpoint. Therefore, TSA has made changes to the staffing 

allocation model for fiscal year 2007 to include line item allocations for t

new Screening Passengers by Observation Techniques, Bomb Appraisal 

Officer, and Aviation Direct Access Scr

Fourth, two of the five FSDs with in-line checked baggage screening 

systems stated that in their view TSA overestimated the TSO labor savi

that would be achieved as a result of deploying in-line baggage scree

systems. TSA headquarters officials responsible for the staffing mode

stated that some adjustments had to be made to individual airports’ TSO

staffing levels to adequately reflect the configuration of the airports’ in-lin

systems, which permit higher throughput rates. Specifically, som

installed at a particular terminal or terminals. Additionally, TSA officials 

cited one example in which a category X airport received a reduct

TSOs in fiscal year 2005 to account for the in-line baggage screenin

system at the airport. However, TSA officials responsible for the staff

model later learned that the model had incorrectly assumed that th

system was fully operational, when in fact it was still under constructio

Officials stated that the FSD at this airport was consequently allocated 

additional TSO positions. TSA officials stated that the model validation 

process currently underw

importance of a mechanism to provide assurance that all assumption

periodically undergo validation. 

46The “Screening Passengers by Observation Technique” involves specially trained TSOs 

observing the behavior of passengers and resolving any suspicious behavior through casual

conversation with passengers and referring suspicious passengers to selectee screening.

Page 37 GAO-07-299 TSA Staffing Standards
Finally, FSDs identified that the model does not account for TSOs being 

used in operational support functions. Eleven of the 14 FSDs we 

interviewed stated that because they are not authorized to hire a suffici

number of mission support staff, TSOs are being routinely used to perform 

certain operational support functions such as payroll processing, 

scheduling, distribution and maintenance of uniforms, data entry, and 

workman’s compensation processing. At 13 airports

ent 

ere

SOs

re

nation’s

airports spent approximately half their time on these duties—38 out of 80 

ming

n

 

47 we visited between

January and August 2006, out of a total of 4,710 TSOs on-board at those 

airports, TSA was using 242 TSOs (about 5 percent) for operational 

support functions. FSDs and their staffs stated that these TSOs w

spending varying amounts of time on operational support duties, some on 

a nearly full-time basis.48 As shown in figure 7, nearly 7 percent of T

nationwide performed operational support (on at least a part-time basis)

during a specific 2-week pay period in fiscal 2006. This percentage was 

slightly higher for the smaller airport categories. Also, as shown in figu

7, the TSOs performing operational support functions at the

possible hours—during the 2-week period. In addition, TSOs perfor

operational support functions at Category X airports spent significantly 

more time on these duties (approximately 63 out of 80 hours) than TSOs i

the other airport categories. 

 irport we visited, San Francisco, from this discussion since it employed

ntractors as screeners. TSA data on use of TSOs in operational support functions 

least 8 hours per week. 

47We excluded one a

private co

do not include airports with private screeners.

48According to a TSA management directive dated December 4, 2006, TSOs must perform

screening duties at

Page 38 GAO-07-299 TSA Staffing Standards
Figure 7: Percent of TSOs Used for Operational Support Functions, along with 

Average Hours Spent by Them on These Functions, by Airport Category for a 2-

Week Period—September 17, 2006, through September 30, 2006 

her personnel to perform this 

ork.

49 The Inspector General reported that during a 15-week period from 

 

0 10 20 30 40 50 60 70

IV

III

II

I

X

Total

Category

Percent (Hours)

Percent of screeners

Average hours used

Source: GAO analysis of TSA data.

6.55

7.94

(22.34)

(62.94)

(38.13)

(32.26)

7.80

8.57

4.45

(29.70)

11.25

(13.89)

Note: This figure includes data on federal TSOs only and not on private screeners employed at the 6 

airports across the nation utilizing these personnel.

In September 2006, in reporting on its review of TSA administrative 

positions, the Department of Homeland Security’s Office of Inspector 

General found that TSA had not determined the precise number of FSD 

administrative positions it needs and was using TSOs to perform 

administrative work due to a lack of ot

w

 49Department of Homeland Security Office of Inspector General, Review of TSA NonScreener Administrative Positions, OIG-06-65, September 2006. 

Page 39 GAO-07-299 TSA Staffing Standards
October 2, 2005, through January 21, 2006, TSOs performed operational 

support work equivalent to 1,441 full-time-equivalent TSO positions, which 

is equivalent to about 78 percent of the 1,850 support staff formally 

strative

a 

e

The number of operational support staff provided to each airport will be 

rt

by

TSA’s use of TSOs to perform operational support functions may 

contribute to scheduling challenges because these TSOs are unavailable 

for their primary responsibilities to screen passengers and their checked 

baggage. For example, an FSD at a category X airport stated that he would 

assigned to do this work. Moreover, the Inspector General reported that 

TSOs were working overtime to perform these duties. The Inspector 

General recommended that, among other actions, TSA conduct a 

workforce analysis of FSD administrative staff and develop a staffing 

model to determine the number of administrative employees needed at 

airports, and take into consideration the time and nature of admini

work performed by TSOs when assessing its workforce requirements. In

May 2006, TSA headquarters officials told us that they were conducting

survey of FSDs to identify the number of hours their staffs, including 

TSOs, spend each week on a variety of operational support functions. 

These officials stated that they will review the FSD responses to determin

the time it takes to perform each function and the level of staffing needed. 

based on the types of administrative functions performed at the airpo

and the availability of funding. TSA headquarters officials stated that they 

have not made a decision on whether permanent operational support staff

would be provided in the form of additional TSOs or full-time

administrative staff. In the interim, TSA contracted with three private 

companies in September 2006 to provide temporary operational support 

services to FSDs that request this assistance from TSA headquarters. 

According to TSA, these contractors supplement FSD administrative staff 

so that TSOs performing operational support functions can return to their 

primary screening duties.

Additionally, in order to account for additional TSO time needed for 

operational support, TSA included a “collateral duties credit” in the 

Staffing Allocation Model for fiscal year 2007. This credit will increase 

each airport’s fiscal year 2007 allocation identified by the staffing model

5 percent at category X, I, and II airports. TSA officials stated that the 

agency is not providing this credit to category III and IV airports because 

the extended periods of low screening demand at these airports offsets the 

need for such an allowance. 

have less of a problem scheduling checkpoints during peak passenger 

volume if he did not have to use TSOs to provide operational support. 

Additionally, the use of TSOs to perform operational support functions 

Page 40 GAO-07-299 TSA Staffing Standards
may undermine TSA’s investment in training them for screening function

since the TSO is not performing the job for which they were traine

Moreover, TSA has stated that TSO performance improves with 

experience. Consequently, TSOs who are not conducting passenger or 

checked baggage screening are not gaining the additional experien

help enhance their performance. An FSD we interviewed at a category

airport stated that having to use TSOs to perform operational support 

duties at his airport has created challenges in keeping these TSOs 

proficient in screening duties. However, TSA headquarters’ officials

that using TSOs to perform operational support functions does not 

adversely impact TSO performance because the agency has various 

methods in place to ensure that all TSOs, including those performing 

nonscreening duties, meet minimum security standards. For example, all 

TSOs have to meet the recurrent training requirement of 3 hours of 

training per week averaged over a calendar quarter to maintain proficiency 

and remain current on procedural changes and new threat items and a

TSOs are subject to the various components of TSA’s performance 

accountability and standards system.

s 

d.

ce to

X

stated

ll

ning program. Nevertheless, TSA officials 

acknowledged that the agency has not examined the impact of using TSOs 

to perform operational support duties on cost, scheduling efficiency, and 

TSO performance. In addition, TSA has not determined under what 

circumstances it is appropriate to use TSOs to perform operational 

support functions or provided FSDs with guidance on when TSOs can be 

used this way. Without establishing such guidance, FSDs may over rely on

TSOs to perform operational support functions. 

 

50 Additionally, TSA officials stated 

that an April 2006 management directive requires TSOs who have not 

performed screening functions for 15 or more consecutive days to 

complete a return to duty trai

50 TSA’s performance accountability and standards system, which was implemented in 

April 2006, will be used by TSA to assess agency personnel at all levels on various 

competencies, including training and development, readiness for duty, management skills, 

and technical proficiency. There are three elements of the TSO technical proficiency 

checkpoint screening standard operating

procedures; (2) quarterly quizzes given to TSOs to assess their knowledge of the 

component of the performance and accountability standards system: (1) quarterly 

observations of TSOs’ ability to perform particular screening functions in the operating 

environment to ensure they are complying with

procedures; and (3) an annual, multi-part knowledge and skills assessment (known as 

recertification testing). 

Page 41 GAO-07-299 TSA Staffing Standards
TSA has vested its FSDs with responsibility for managing their TSO 

allocations while considering local circumstances that can affect the 

staffing allocation model’s effectiveness in deploying the TSO workforce.

tion

ing

the model. Nonetheless, this stated allocation is only a starting point. 

Throughout the fiscal year, FSDs are responsible for preparing TSO work 

schedules that adapt to changing circumstances at the local level. 

a

TSA’s FSDs Are 

After receiving the annual FTE allocation from TSA headquarters, the FSD 

and his or her staff must prepare TSO work schedules, by using the 

staffing model’s optional scheduling tool or some other method, to ensure 

that adequate numbers of TSOs are conducting passenger and baggage 

screening operations, at all times, to ensure adequate security and attempt 

to meet the 10 minute wait time standard. However, factors outside the 

model’s determination of overall staffing levels can affect FSDs’ ability to 

effectively schedule TSOs at passenger lanes and baggage check areas. For 

example, as previously discussed, few airports have been able to achieve a 

20 percent FTE level for part-time staff as assumed by the staffing 

allocation model in its first 2 years of implementation (fiscal years 2005

and 2006)—forcing FSDs to adjust the scheduling tool based on actual

part-time TSOs on board. Also, as of September 30, 2006, approximately 

one-third of airports had less than 90 percent of their overall TSO 

positions filled, and nine of the 14 airports we visited were similarly below 

their staffing allocation. FSDs cited certain other challenges in scheduling

TSO staff including injuries and absenteeism, in addition to time spent 

away from screening duties due to training requirements and operational 

support needs—factors that the scheduling tool did not directly consider 

in fiscal years 2005 and 2006. As previously discussed, to address some of 

these difficulties, TSA has revised some of the assumptions in the Staffing

Allocation Model for fiscal year 2007. To address other difficulties, TSA 

has implemented several human capital initiatives to improve hiring and 

retention of TSO staff, lessen the impact of injuries and absenteeism, and 

study the impact of training and operational support demands on TSO 

time. TSA has not yet assessed the impact of these initiatives on hiring and 

retention, but plans to do so during fiscal year 2007. 

FSDs are responsible for deploying and managing to their TSO alloca

in light of local circumstances, including those that might affect 

scheduling and pose challenges to most efficiently deploying their 

resource allocations. At the beginning of each fiscal year, the staff

allocation model identifies the annual allocation of TSOs needed at each 

airport based on projected demand levels and other factors that make up

Responsible for 

Deploying TSO 

Allocations at their 

Airports, but Face 

Workforce and Other 

Challenges to 

Effective Deployment 

FSDs Are Responsible for 

Managing to Their TSO 

Staffing Allocation in Light 

of Local Circumstances 

Specifically, FSDs are responsible for scheduling TSOs to ensure that

Page 42 GAO-07-299 TSA Staffing Standards
sufficient number of TSOs are deployed, from available staff, to meet 

airport screening needs.

TSA has provided FSDs with an optional tool they can use to facilitate the 

management of their TSO allocation. Specifically, the Staffing Allocat

Model includes a scheduling component that uses the various inpu

and assumptions of the model, including the number of checkpoints, la

and checked baggage screening machines needed to respond to the 

passenger and checked baggage load and the minimum TSO staffing levels

identified in the standard operating procedures for passenger and checke

baggage screening. This tool is then to produce daily workforce 

requirements and calculates a work schedule for each airport. The 

schedule identifies a recommended mix of full-time and part-time staff

a total number of TSO FTEs needed to staff the airport on a given day, 

consistent with a goal of 10 minutes maximum wait time for processing 

passengers and baggage. In addition, there are several areas where TSA 

adjusts the scheduling tool to most accurately reflect actual conditions 

and needs. These areas include: 

• Flight schedule changes.

• TSO training requirements (based on available times identified by t

scheduling tool). 

• Number of TSOs needed for operational support associated with 

operating the checkpoint and baggage screening areas. 

• New passenger and checked baggage screening procedures that affect

TSO utilization. 

ion

ts to

nes,

d

and

he 

tive

nal flight schedules and anticipated passenger 

volume as late as 1 week in advance—sometimes leaving FSDs little time 

r to

on

FSDs stated that because the scheduling tool does not contain this 

information, they must modify the input to the tool, or use an alterna

scheduling tool, to deploy their TSO workforce. For example, FSDs and

their staffs stated that the scheduling tool does not contain the most 

current flight schedule data due to the reporting practices of various 

airlines. During our airport visits, TSA scheduling officers reported that 

the scheduling tool includes data from as much as 90 days in advance, but

some airlines provide their fi

to ensure adequate TSO availability. TSA officials said that in orde

keep their flight offerings competitive, airlines seek to protect their flight

data from public disclosure as long as possible. For this reason, TSA 

headquarters officials said they expect FSDs to work with airport 

operators and airline officials to obtain the most current data available

which to base their scheduling efforts and to make adjustments to the 

Page 43 GAO-07-299 TSA Staffing Standards
scheduling tool to ensure that their deployment of TSOs most effectively 

meets the screening demand. 

The nine FSDs we interviewed at category X and I airports reported tha

the scheduling tool was useful as a starting point for developing their 

schedules. However, all six FSDs who said they used the scheduling tool 

regularly reported making adjustments to the schedule output to more

accurately reflect their local conditions primarily because, accordi

these FSDs, the scheduling tool does not automatically take into account

the actual composition of the TSO workforce at each individual airp

in some cases, unique work schedules that may be implemented at so

airports (other than a standard 5-day work week). For example, the 

scheduling tool is based on the model’s assumption of a 20 percent parttime force expresses as a full-time-equivalent level among available

although few of the larger airports have been able to achieve this level of 

part-time staff. Specifically, only 2 of the 26 category X airports had a 

workforce composed of at least 20 percent part-time staff in July 20

Because the scheduling tool assumes a 20 percent part-time level for TSO

FSDs at airports we visited with lower levels of part-time TSOs stated

they make adjustments to the scheduling tool’s output to more accu

reflect the airport’s actual mix of full-time and part-time TSOs and then 

develop a work schedule accordingly. In addition, as of September 30, 

2006, TSA data showed that approximately one-third of the nation’s 

airports had less than 90 percent of their annual TSO positions filled

According to FSDs we interviewed, however, the scheduling tool ass

that each airport has its full TSO allocation on board. Moreover, according 

to TSA, the scheduling tool assumes that TSOs across all airports have 

standard 5-day work weeks, although individual a

t

ng to

ort or, 

me

staff,

06. 

s, 

that

rately

.

umes

irports may require TSOs 

to work varying schedules. For example, an FSD for a category III airport 

told us that he requires TSOs to work a sixth day once every 4 weeks. 

However, the FSD at this airport stated that the scheduling tool cannot 

account for this schedule. 

In response, TSA headquarters officials stated that the scheduling tool can

indeed account for the actual number of onboard TSOs, the actual mix of 

 

full-time and part-time TSOs, and most scheduling anomalies FSDs 

encounter.51 The TSA headquarters officials attributed the FSDs’

comments to misunderstandings regarding the full capabilities of the 

 re

 However, other variations within the 5 days are possible. 

51 TSA officials acknowledged that the scheduling tool cannot be adjusted to reflect mo

than a 5-day work week.

Page 44 GAO-07-299 TSA Staffing Standards
scheduling tool. The officials further explained that the agency has d

better job recently in training field staff in the use of the scheduling to

than was done earlier in the Staffing Allocation Model’s implementation.

one a 

ol

d that

only 

to 

A 

O staff to schedule,

according to TSA officials. After these technical improvements are made, 

hich TSA expects to be completed in fiscal year 2007, TSA officials told 

eduling 

f

 

52

FSDs at the four smaller (category II and III) airports we visited state

the scheduling tool was more useful for larger airports with more complex

scheduling challenges given the size of the workforce, the higher 

passenger volumes, and the larger number of checkpoints and terminals. 

These FSDs stated that smaller airports can more easily predict their 

screening demand and generally said they did not believe that the staffing 

model’s scheduling tool added value to their scheduling process—

especially since they are dealing with small numbers of TSO staff and 

limited passenger and baggage check facilities, for example, having

one checkpoint with few lanes. Therefore, they have chosen to continue

use such locally developed tools, such as spreadsheets. However, TSA 

headquarters officials stated that use of the scheduling tool by all airports

will eliminate applications, such as these spreadsheets, that are 

inconsistent with the Staffing Allocation Model and TSA’s time and 

attendance reporting system, thereby enhancing efficiency in scheduling

TSOs. 

While TSA headquarters officials stated that the scheduling tool is capable

of preparing schedules for any size airport and accounting for all the 

issues noted as problems by the FSDs we visited, officials are currently 

permitting each FSD to determine whether to use the scheduling tool. TS

officials stated that technical improvements planned for the scheduling

tool will improve its usefulness in preparing TSO schedules. For example,

installation of high-speed internet connectivity and implementation of 

electronic time and attendance reporting will allow the scheduling tool to

efficiently maintain up-to-date rosters of available TS

w

us they may consider making the tool mandatory. 

According to TSA, electronic time and attendance will improve sch

by providing connectivity between the scheduling tool and TSA’s 

timekeeping system. This automation is to enable the automatic linking o

 f 52 We did not assess the adequacy of training of FSDs because it was outside the scope o

our work. 

Page 45 GAO-07-299 TSA Staffing Standards
scheduling and timekeeping information and provide planned schedule

and actual time worked. 

s

ace

el of not 

ed on

r allocation were among the small 

category III and IV airports. Conversely, as also shown in figure 8, 131 of 

cent of their TSO allocations are airports in 

smaller numbers of TSOs; therefore, even small staff fluctuations have a 

l,

mo

All 14 FSDs we interviewed identified challenges they faced in deploying

their TSO workforce. Nine of the 14 airports we visited were below their

allocation for TSOs as determined by the staffing model. FSDs at these 

airports cited the inability of TSA’s centralized hiring process to repl

TSOs quickly. However, attrition, particularly by part-time TSOs, was also 

cited as a barrier to achieving and maintaining their TSO staffing levels. 

TSA has stated a goal of each FSD maintaining a TSO staffing lev

less than 90 percent of each individual airport’s TSO allocation. Bas

TSA data, approximately 53 percent (237) of commercial airports were 

either at, or no less than 10 percent below, their respective TSO 

allocations at the end of fiscal year 2006. Approximately 31 percent of 

airports (140) were below 90 percent of their allocation, and 16 percent 

(71) of airports were 110 percent or more above their allocation.53 Sixtynine of the 71 airports above thei

the 140 airports below 90 per

categories II, III, and IV. These smaller airports have correspondingly 

greater impact on being above or below their TSO allocations. Overal

re large airports (categories X and I) have succeeded in meeting their 

TSO allocations determined by the Staffing Allocation Model.

 t 

ly

cent) to

allocation. 

FSDs Cited Challenges in 

Deploying Their TSO 

Workforce to Perform 

Screening, and Several 

Efforts Are Underway to 

Address These Challenges 

53 Due to TSA’s expectation that FSDs maintain on-board TSO staffing of at least 90 percen

of their TSO allocation, in addition to significant numbers of airports falling marginal

above and below 100 percent, we used a 20 percent range (90 to less than 110 per

determine how many airports were above and below their allocation in terms of on-board 

TSOs. That is, airports with less than 90 percent of their allocation were “below” their

allocation and airports with 110 percent or more of their allocation were “above” their

Page 46 GAO-07-299 TSA Staffing Standards
Figure 8: Airports’ On-Board Status, by Airport Category, Compared to TSO Staffing Allocation, in Full-Time-Equivalent TSOs,

as of September 30, 2006 

the

6 airports across the nation utilizing these personnel. 

According to TSA officials, airports that are above their allocation must 

237

1

25

Total X

Total: 448 Total: 26

Source: GAO analysis of TSA data.

Below allocation (on-board TSOs less than 90% of allocation)

Meets allocation (on-board TSOs range from 90% to less than 110% of allocation)

Exceeds allocation (on-board TSOs at 110% or more of allocation)

140

17

55

42

II III

Total: 114

18

55

Total: 73

8

44

Total: 54

I

52

58

71

IV

Total: 181

71

2

Note: This figure includes data on federal TSOs only and not on private screeners employed at

reduce their TSO staffing levels by either (1) attrition or (2) transferring 

their excess TSOs to airports that are below their allocation. TSA officials 

Page 47 GAO-07-299 TSA Staffing Standards
also stated that airports grouped together under TSA’s “hub and spoke” 

organizational structure often share TSO resources as needs dictate.54 

FSDs we interviewed cited various reasons for attrition, including limited 

e

ar

 

advancement opportunities, need for higher paying job, work hours, 

difficulty of work, and job dissatisfaction. At the same time, as shown in 

figure 9, TSO attrition rates, for both full-time and part-time staff, 

decreased from approximately 24 percent to 21 percent from fiscal year 

2004 to fiscal year 2006. However, as previously discussed, the part-tim

TSO attrition rate remains considerably higher than the rate for full-time 

personnel (approximately 46 percent versus 16 percent for fiscal ye

2006). 

54TSA implemented its “hub and spoke” organizational structure in fiscal year 2006 to allow

ategory X and I airports and other smaller airports in their geographic vicinity. 

for sharing of management, TSO and operational support staff, and other resources among

individual c

Page 48 GAO-07-299 TSA Staffing Standards
Figure 9: Attrition Rates for Full-Time and Part-Time TSOs, Fiscal years 2004 to

2006 

0

10

20

30

40

50

60

70

80

90

100

2004 2005 2006

Percent

Source: GAO analysis of TSA data.

Fiscal year

Part–time attrition

Total attrition

Full–time attrition

Note: This figure includes data on federal TSOs only and not on private screeners employed at the

6 airports across the nation utilizing these personnel. 

According to the Office of Personnel Management, an important principle 

behind maintaining a quality workforce is employee retention, and an 

analysis of workforce trends is essential to determine what factors most 

affect retention. To this end, in August 2005, TSA hired a contractor to 

administer exit surveys during fiscal year 2006 to employees who 

voluntarily separated from TSA. While the response rate, as of July 2006, 

was too low (15 percent) to draw overall conclusions about the results, 

TSA stated that the most common reasons cited by TSOs for separating 

from TSA include better job opportunities, dissatisfaction with TSA 

leadership, and personal reasons. For part-time TSOs, the most common 

reasons were better job opportunity, personal reasons, dissatisfaction with 

their supervisor and undesirable work schedule. TSA plans to conduct 

further analysis of the responses based on whether the TSO was a full-time

Page 49 GAO-07-299 TSA Staffing Standards
or part-time employee in an effort to determine the unique issues facing 

each group. TSA officials stated that nearly half (47%) of the survey 

respondents said that they would consider returning to TSA.55 TSA has 

acknowledged that the high attrition rates drive up hiring and training 

costs. TSA officials stated that it costs about $10,000 to assess, hire, and 

train a TSO. Officials estimated that for every 2,500 TSOs that TSA retains, 

including part-time TSOs, TSA could save about $25 million. 

Five of the 14 the FSDs we interviewed cited either generally high levels of 

absenteeism56 or injuries as factors that affect their ability to schedule 

TSOs to passenger lanes and baggage screening areas. The Assistant 

Secretary of Homeland Security for TSA has also identified high

absenteeism and injury rates as major causes of staffing shortages. While

absenteeism and injuries remain prevalent among the TSO workforce, TSA 

data indicate overall improvement in these problem areas. As shown in 

figure 10, TSO absenteeism rates, across all airport categories, have

improved from fiscal year 2004 to fiscal year 2006. 

 55 According to TSA, the survey respondents were from all of TSA’s employees, not just

TSOs. However, TSA did isolate certain responses by TSOs. 

56 TSA defines absenteeism in terms of unscheduled absences and tardiness among the TSO

workforce. Unscheduled absences include calling in sick the day of work, arriving two or 

ore hours late, being AWOL, or otherwise failing to show. Absenteeism does not include

ose TSOs previously approved to be on any kind of leave or TDY such as, annual leave, 

y

m

th

pre-arranged sick leave, military leave, jury duty, training, etc. TSOs are “tardy” when the

are 1 or more minutes late for their designated shift. TSOs who are more than 2 hours late

are counted as unscheduled absences. 

Page 50 GAO-07-299 TSA Staffing Standards
Figure 10: Average Rate of TSO Absenteeism per 100 TSOs, by Airport Category,

for Fiscal Years 2004 - 2006

Fiscal year

Percent

Total

X

I

II

III

IV

Source: GAO analysis of TSA data.

0 1 234 5 6 7 8 9 10 11

2006

2005

2004

1.61

2.16

3.56

5.29

7.38

3.95

1.36

4.63

8.24

6.06

4.67

2.57

5.87

7.62

10.52

6.16

3.13

1.91

Airport categories

Note: This figure includes data on federal TSOs only and not on private screeners employed at the 6 

airports across the nation utilizing these personnel.

In addition, as shown in figure 11, TSO injuries (as represented by 

workman’s compensation claims) have improved over the same period 

(fiscal year 2004 to 2006). TSA headquarters officials attributed this 

improvement to the agency’s initiatives to reduce injuries among the TSO

workforce. 

Page 51 GAO-07-299 TSA Staffing Standards
Figure 11: TSA Workman’s Compensation Claims for Calendar Years 2004 - 2006,

through June 2006

TSA headquarters officials stated that, nationwide, excessive use of 

overtime has not been a problem and is mostly used to address attrition, 

one-time events, unexpected delays, and holidays. Figure 12 shows that 

Calendar year

Number of claims

Total

X

I

II

III

IV

Source: GAO analysis of U.S. Department of Labor data.

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000

2006

2005

2004

177

145

358

1,183

2,267

3,984

36

12,395

6,950

3,628

1,121

429

15,972

5,365

8,429

1,579

514

85

Airport categories

Note: The data in this figure include all workman’s compensation claims received by the Department 

of Labor from TSA and are not limited exclusively to TSOs. However, TSA officials stated that the 

vast majority of these claims are from their TSO workforce. 

Despite the acknowledgement of problems with attrition and absenteeism, 

Page 52 GAO-07-299 TSA Staffing Standards
TSA’s use of overtime, which does not count against the full-timeequivalent rate at airports, has remained relatively stable—4 to 5 

percent—during fiscal years 2004 through 2006 with larger airports 

generally having higher overtime rates each year. 

Figure 12: TSO Overtime Hours as a Percentage of Total Hours Worked, by Airport 

Category, during Fiscal Years 2004 - 2006 

Fiscal year

Percent

Total

X

I

II

III

IV

Source: GAO analysis of TSA data.

0 1 2 3 4 567

2006

2005

2004

3.52

3.31

3.60

4.60

6.98

4.35

3.28

4.36

6.13

4.84

3.94

3.36

4.56

4.86

6.44

3.78

3.56

4.15

Airport categories

Note: This figure includes data on federal TSOs only and not on private screeners employed at the 6

airports across the nation utilizing these personnel.

Page 53 GAO-07-299 TSA Staffing Standards
FSDs we spoke to cited a need to use TSOs for various operational 

support functions on either a full-time or part-time basis due to a lack of 

sufficient administrative staff to perform these functions. As previously 

oncerned about wait times at the 

irport. The air carrier established a security process improvement team 

thority

s

air

n removing cell phone, keys, change, and other metal objects 

noted, these functions included such activities as payroll and workman’s 

compensation processing, various data input related to screening 

operations, uniform management and control, and managing and 

distributing supplies for the checkpoints. As a result of devoting at least a 

portion of their time to these activities, FSDs could not rely on these TSOs 

to perform all of their other passenger and baggage screening activities 

during these periods. 

Another challenge to using the model to deploy TSOs, according to TSA 

headquarters officials and FSDs, is that some airports have physical 

infrastructure configurations that limit their capacity for processing 

passengers and checked baggage that cannot necessarily be accounted for 

in the Staffing Allocation Model. At these airports, longer wait times are 

due, at least in part, to limitations on the number of screening lanes 

available, a limitation imposed by the layout of the checkpoint. TSA 

officials stated that in some of these instances, airports have made capital

improvements to increase capacity and help minimize wait time. Of the 14 

airports we visited, 7 had made, or were in the process of making, capital 

improvements to expand the passenger processing capacity of their 

security screening checkpoints. For example, during the period of October

2004 to June 2005, a category I airport experienced wait times exceeding 

40 minutes on 40 separate occasions. TSA determined that wait times 

could not be reduced at the airport, even if it deployed more TSOs, due to 

the physical construction of the checkpoint, which only allowed for four 

screening lanes. In June 2005, the airport removed a wall to enable the

installation of additional screening lanes. As a result of the additional 

lanes staffed with TSOs during peak periods, the airport only experienced

one instance of a reported wait time exceeding 40 minutes as of October 

2006. 

In addition to airports making capital improvements to help address 

capacity issues, airports and air carriers have also taken action to assist 

with increasing the efficiency of the screening process. For example, an 

air carrier at a category X airport was c

a

consisting of representatives of TSA, air carriers, and the airport au

to examine checkpoints and suggest ways to make the screening proces

more efficient. One initiative that resulted from this effort is that the

carrier provided staff at passenger screening checkpoints to assist 

passengers i

Page 54 GAO-07-299 TSA Staffing Standards
from their person before going through the walk through metal detector. 

According to the air carrier, it spent about $15,000 to $18,000 of its own 

money each month in personnel costs to staff the checkpoints over a 12-

eSO retention, utilization, and 

ffectiveness. 

TSA Reported Several 

Efforts Underway to Help 

Address Challenges in 

Deploying the TSO 

Workforce 

hour period most days. In another case, a representative of an airport 

board for a category X airport told us that in response to concerns about 

high wait times—wait times exceeding 30 minutes—the airport board 

spent $1 million to hire a consultant to simulate existing checkpoint 

configurations and conditions to determine where and how improvements 

could be made to increase passenger throughput, thereby reducing wait 

times. As a result of this effort, several improvements were made, 

including posting a TSO at the front of each checkpoint to facilitate the 

screening process, posting signage at checkpoints to explain the items that 

passengers should remove from their person; adding space at end of the xray screening belt so that passengers can easily pick up their items without 

holding up the line; and providing more room for passengers to remove 

items from their person before they get to the x-ray machines. According

to this airport official, these improvements collectively resulted in an 

increase in passenger throughput from 175 to 200 passengers per hour at 

relatively low cost. However, the official expressed concern that most 

airports are not in a position to fund similar projects because they do not 

have the resources. 

TSA headquarters officials and FSDs we interviewed reported having 

several efforts underway to help address some of the challenges they face 

in deploying the TSO workforce. For example, to allow FSDs to more 

efficiently address staffing needs, TSA has shifted responsibility for hiring 

TSOs from TSA headquarters to FSDs at individual airports and, according

to TSA officials, provided contractor support to assist in this effort. TSA 

data show that since local hiring began in March 2006, TSA has increased

the number of new hire TSOs from approximately 180 per pay period in 

February 2006 to nearly 450 each pay period under the local hiring 

initiative. Additionally, TSA officials stated that prior to the 

implementation of the local hiring initiative, TSA was able to support 

hiring at only about 30 airports during any given period compared to more 

than 100 airports each pay period since the local hiring initiative was 

implemented. Table 4 provides a summary of the national human resourc

related initiatives intended to help increase T

e

Page 55 GAO-07-299 TSA Staffing Standards
Table 4: National Human Resource Initiatives by TSA for Its TSO Workforce 

Human resource challenge TSA initiative Description

Local hiring y for hiring TSOs from TSA 

Headquarters to the FSDs at individual airports. TSA headquarters 

has provided contract personnel to assist airports in all aspects of the 

TSA Staffing Standards

In March 2006, TSA shifted responsibilit

hiring process. 

TSO Caree

Program 

r Progression Recognizing that the screener workforce had few upward mobility 

opportunities within their profession, TSA reclassified the agency’s 

43,000 screeners as TSOs. This new classification gives TSOs an 

opportunity for career progression and to apply for DHS law 

enforcement positions. Through this program, TSA has implemented 

new pay bands that broaden TSO career opportunities and include 

“technical” and “leadership” career track options for the TSOs. 

Performance-based pay In April 2006, TSA deployed a pay-for-performance system.

Retention incentive payments During fiscal year 2006, TSA offered bonus payments in installments 

to TSOs who stay with the agency for a certain period of time. TSA is 

also providing a $500 separate retention incentive for full-time TSOs

at 22 hard-to-hire airports. TSA made the first of these payments in 

May 2006. 

Full-time to par

conversion b

t-time 

onus 

In fiscal year 2006, TSA provided bonus payments in May and 

September to full-time TSOs who decided to convert to part-time 

status by May 1, 2006. 

TSO Incentive Awards In fiscal year 2006, TSA provided monetary support to FSDs to assist 

them in retaining TSOs with good performance records. During the 

year, FSDs received $20 million to be paid to TSOs’ to reward 

superior performance. 

Part-time health benefits pilot TSA has implemented a pilot program at 6 airports providing parttime TSOs with the same benefits as full-time TSOs . 

Career co

inventory 

aching/skills TSOs can speak one-on-one with a career counselor and complete a 

self-assessment to determine their needs for advancement. 

Hiring and retention of 

adequate numbers of TSO

staff (including part-time) 

Lifecare TSA offers this service, free-of-charge, to TSOs to assist them with 

eldercare, daycare, or other issues that can affect their work life and 

keep them from performing effectively. 

Absenteeism Performance-based pay TSO pay based, in part, on attendance. 

TSO

Program 

 Career Progression By enhancing the motivation of TSOs, TSA believes this program will

help improve attendance. 

Nurse case

program 

 management TSA acknowledged that TSO injuries were a significant drain in its 

workforce and responded by creating an agencywide nurse case 

management program based on the recommendations of the TSO

Injury Task Force. This program assists TSOs in getting the medical

attention they need to return to work as soon as possible. 

Injuries 

Industria

problem airp

could significantly reduce injury rates. 

l engineer visits to 

orts 

TSA Headquarters is in the process of sending teams of industrial 

engineers to evaluate the 25 airports with the worst injury rates and 

make recommendations for improvements, including simple

configuration changes and small equipment purchases (like roller 

tables and floor mats) that

Source: TSA. 

Page 56 GAO-07-299 
In addition to these workforce initiatives, TSA also continues to use

from the national screening force to address short-term needs at individu

airports nationwide. According to TSA, the national screening force is 

generally deployed only to those airports experiencing significant staffing

shortfalls associated with increased seasonal traffic or when a spe

event—such as a Super Bowl or a large national conference—occu

requiring an immediate influx of additional, though temporary, TSO 

support. Of the 14 FSDs we interviewed, 6 stated that they had used the 

national screening force at least once. All but one of these FSDs told us 

that the national scree

TSOs

al 

cial

rs

ning force was used to meet short-term screening 

demand associated with special events and unexpected circumstances, 

a.

ause

to

s

e

t

me

its.

s include (1) parking allowances, (2) child care, (3) elder care, and 

(4) tuition assistance. 

r TSOs

such as heavy passenger loads stemming from hurricanes Katrina and Rit

In the other instance, at a category X airport, the FSD stated that, bec

of challenges in hiring and retaining TSOs for this airport, he has had

rely on about 60 members of the National Screening Force deployed to his 

airport since 2004. However, in November 2006, TSA officials stated that

as of November 1, 2006, there were no National Screening Force TSO

assigned to this airport, which they attributed to TSA’s local hiring 

initiative. 

TSA officials stated that they are examining methods for addressing hiring

and retention challenges at specific airports where these problems ar

particularly acute. For example, as shown in table 4 above, TSA has 

implemented a $500 retention incentive for TSOs at 22 “hard-to-hire” 

airports who were on-board as of April 15, 2006. As also shown in the 

table, to help with hiring and retention of part-time TSOs, TSA is piloting a

program that offers full health benefits to part-time TSOs at six airports. A

these airports, part-time TSOs receive the same health benefits as full-ti

TSOs. At all other airports, part-time TSOs do not receive health benef

In addition to incentives and expanding health benefits, TSA is considering

other options for attracting and retaining TSOs. For example, these 

option

In addition to the national initiatives underway, several FSDs at the 14 

airports we visited were implementing their own local initiatives to 

address some of the staffing challenges they faced at their airports. For 

example, after receiving local hiring authority under the nationwide local

hiring initiative, one FSD we spoke to stated that he puts brand-new TSO 

hires out on the passenger lanes as “helpers” so that they may better 

understand what the job entails. He expects that this will cut down on 

attrition at his airport and help reduce wasted training resources fo

who leave within short periods of being hired. Regarding absenteeism, all 

Page 57 GAO-07-299 TSA Staffing Standards
the FSDs we spoke to stated that they monitored unscheduled absences 

and counseled TSOs as needed. To help reduce the number of on the job

injuries, 6 of the 14 FSDs we interviewed said they had local initiatives, 

such as injury prevention committees and detailed instruction on safe 

lifting techniques. To help mitigate inadequate numbers of part-time TSOs

two TSA managers we interviewed said that they asked some of their fu

time TSOs to work “split” shifts to cover demands in peak periods tha

would normally go to part-time TSOs, one of whom might work the first 

peak period shift and another who might work the second peak period 

shift. The result was that it eliminated the staffing of full-time TSOs

non-peak periods when they were most likely to be idle. The experience

these managers illustrates an attempt at an efficient use of TSOs and also 

the primary reason that TSA has tried to achieve a mix of 20 percent parttime to 80 percent full-time TSOs. Specifically, using part-time TSOs can 

help to permit adequate staffing during peak periods while avoiding the 

consequent overstaffing stemming from having the same number of TSOs

on duty during non-peak periods. Additionally, to maximize the flexibi

in staffing passenger and checked baggage screening checkpoints, 3 of the 

10 FSDs whose TSOs were not all dual-trained stated that they were 

working to increase the number of dual-trained TSOs—TSOs trained and 

certified in both pass

,

llt

during

of 

lity

enger and checked baggage screening. Four of the 

14 airports we visited already had dual-trained TSOs at the time of our 

isits.

ent 

nite TSO 

has

tablished several mechanisms to monitor the sufficiency of 

the model’s outputs and make adjustments in key model assumptions, for 

specific airports, that are not accurate for those airports. We also 

recognize that TSA has reviewed and changed several key assumptions for 

fiscal year 2007 that affect all the nation’s airports. While TSA has taken 

Conclusions 

v

Given that many of TSA’s workforce initiatives were only recently

implemented or are in the planning stages, we could not assess the ext

to which these initiatives achieved the intended results. TSA human 

capital officials told us that they plan to establish performance metrics to 

use in evaluating their workforce initiatives and use the results of the 

evaluations to make any needed changes to their approach. 

TSA’s use of a staffing allocation model to help allocate its fi

resources in a manner that ensures security and minimizes wait times

helped guide its allocation of resources. While we recognize the difficulty

in developing precise assumptions given the dynamic nature of the 

aviation industry, the assumptions used in the staffing allocation model 

should reasonably reflect actual operating conditions. We are encouraged 

that TSA has es

Page 58 GAO-07-299 TSA Staffing Standards
steps in the right direction, wit

and prioritizing which assumptions to 

hout a management control for selecting 

systematically review each year and

for assuring that all assumptions are periodically reviewed—a particular 

concern considering the dynamic nature of the aviation industry and the 

ongoi el changes experienced by the agency—TSA is missing an

opportunity to increase its assurance that the model reflects actual 

oper tions over time.

Given the extent to which TSOs hav

support functions at airports, TSA h

first taffing allocati e 

that FSDs may have to rely on TSOs ties

at some times. However, overrelian

limits the availability of TSOs to pe

perform, contributes to challenges i

number of TSOs are at the right che

the investment TSA has made in tra

could over time limit on-the-job trai

important for TSA to determine under what circumstances it is 

appr se TSOs to perf

provide F s with guidance on whe can be used this way. 

To as its efforts to id

reflect the operating conditions at i

that TSOs are effectively utilized, we recommend that the Secretary of 

Homeland Security direct the Assis

Security to take the following two a

• Estab a formal, documented

assumptions in the Staffing Allo

ensur he assumptions res staffing allocations that

accur eflect operating conditions that may change over time. 

• Es olicy for when T

support. 

We p draft of this repo

February 7, we received written comments on the draf

which are reproduced in full in appendix III. DHS concurred with our 

findings and recommendations and stated that the findings and 

recommendations are constructive and useful. 

Recommendations for 

ng personn

ating condi

e been used to perform operational

as directly accounted for this for the

time in the s on model for fiscal year 2007. We recogniz

to perform operational support du

ce on TSOs for operational support

rform the functions they were hired to

n scheduling TSOs so that the right 

ckpoints at the right times, undermines

ining them in screening functions, and 

ning opportunities. Therefore, it is

opriate to u

SD

orm operational support functions and to 

n TSOs

sist TSA in entify TSO staffing levels that reasonably

ndividual airports and to help ensure

tant Secretary for Transportation 

ctions:

lish

e that t

ately r

plan for reviewing all of the 

cation Model on a periodic basis to 

ult in TSO

tablish a p SOs can be used to provide operational

rovided a

26, 200

rt to DHS for review and comment. On

t report, 

Executive Action 

Agency Comments 

and Our Evaluation 

Page 59 GAO-07-299 TSA Staffing Standards
TSA also provided comments on our draft report, which are also 

reproduced in full in appendix III. In its comments, TSA stated that the 

conclusions of our study are valuable, but TSA wants to ensure that a full 

and current picture of the state of its workforce management is portrayed.

TSA of the w as

implemented. These initiatives wer

provided and TSA for comm

Rega r recommendation

plan for reviewing all of the assump

on a periodic basis, DHS concurred

implementing this recommendation as part of its review of the Staffing 

Alloc el assumptions f that

TSA has developing a formal and systematic process that would 

identify a . 

We a ed that, as part al

studies a irical data to valida s—

methods that should enhance the v A’s efforts. TSA also plans

to document this new assumption validation process and have it approved 

by senior leadership. 

DHS also rred with our recom

when TS be used to provide t

TSA’s Offices of Security Operation

together to develop a policy that wo

to provide operational support. DH xpects that the 

final ll provide a greate

FSDs concerning the use of TSOs in

We will s pies of this report t

the Assistant Secretary of Homeland Security for 

interested congressional committees as appropriate. 

highlighted several 

to DHS

orkforce management initiatives it h

e already discussed in the draft report 

ent.

rding ou that TSA establish a formal, documented 

tions in the Staffing Allocation Model

and stated that TSA has already begun

ation Mod

begun

nd prioritize the staffing model assumptions for periodic review

or fiscal year 2007. DHS also stated

re encourag

nd emp

of this process, TSA plans to use form

te the staffing model’s assumption

alidity of TS

concu

Os can

mendation to establish a policy for

operational support. DHS stated tha

s and Human Capital are working 

uld define when TSOs might be used

S also stated that TSA e

policy wi

end co

r degree of structure and guidance to 

operational support positions. 

o the Secretary of Homeland Security; 

Transportation; and 

Page 60 GAO-07-299 TSA Staffing Standards
If you or your staff have any questions about this report, please contact m

at (202) 512-4523 or leporeb@gao.gov. Contact points for our Offices of 

Congressional Relations and Public Affairs may be found on the last page 

of this report. GAO staff that made major contributions to this report are 

listed in appendix IV. 

e

Brian J. Lepore 

Acting Director 

Homeland Security and Justice 

Page 61 GAO-07-299 TSA Staffing Standards
Appendix I: Objectives, Scope, and 

Methodology 

The Intelligence Reform and Terrorism Prevention Act of 2004, enacted in

December 2004, required the Transportation Security Administration 

(TSA) to develop and submit to the Senate Committee on Commerce, 

Science, and Transportation, and the House of Representatives Committee

on Transportation and Infrastructure, standards for determining the 

aviation security staffing for all airports at which TSA provides or overse

screening services by March 2005.

es

’s

nced by passengers is minimized, we addressed the following 

questions: 

rform

• How does TSA deploy its TSO allocation and what factors affect the 

model’s effectiveness in helping TSA accomplish this deployment? 

SA

staff at

 

1

 These standards are to provide the 

necessary levels of aviation security and ensure that the average aviation

security-related delay experienced by passengers is minimized. This 

provision of the act also mandated that we conduct an analysis of TSA

staffing standards. To assess TSA’s efforts in developing a staffing 

allocation model that ensures that it provides the necessary levels of 

aviation security and that the average aviation security-related delay

experie

• How does TSA ensure its Staffing Allocation Model provides a 

sufficient number of Transportation Security Officers (TSO) to pe

passenger and checked baggage screening at each airport and what 

challenges has it faced while implementing the model? 

Our work generally focused on the two major components of TSA’s 

determination of TSO staffing at the nation’s airports. First, at the T

headquarters level, we interviewed (and reviewed documentation 

provided by) officials responsible for the development, implementation, 

and ongoing monitoring of the Staffing Allocation Model and its 

determination of the annual allocation of TSOs to each of the nation’s 

commercial airports. Second, at the field level, we interviewed TSA

selected airports who were responsible for working within their allocation 

to deploy sufficient TSO staff to their airports’ passenger and checked

baggage screening operations. 

1

 Pub. L. No. 108-458, § 4023, 118 Stat. 3638, 3723-24 (2004). 

Appendix I: Objectives, Scope, and 

Methodology 

Objectives 

Scope and 

Methodology 

Page 62 GAO-07-299 TSA Staffing Standards
Appendix I: Objectives, Scope, and 

Methodology 

During our design phase, we visited six airports selected based on 

location, airport category,

2

 and participation in TSA’s Screening 

Partnership Program.3

 Table 5 provides information on the airports we 

visited during the design phase. 

Table 5: Airports Visited during Design Phase 

Geographic location 

Airport 

category 

Screening

Partnership 

Program 

participation

Texas: 

• Dallas/Ft. Worth International Airport 

• William P. Hobby Airport 

X 

I 

No 

No 

• Waco Regional Airport III No 

Washington, D.C. (Metro): 

• Washington-Dulles International 

Airport 

• Washington-Regan National Airport 

X 

X 

No 

No 

California: 

• San Francisco International Airport Yes Yes 

Sou ce: GAO review of TSA data. 

er completing the design phase of our study, we visited eight additio

ports, shown in table 6, representing a geographic mix of large and 

r

Aft nal

air

small airports. We select

np ,

4

 but which have significantly different passenger wait times 

 

ed these airports by choosing two airports in each 

of categories X, I, and II with a similar number of annual passenger 

e lanements

 sk

of

7 (2001), 

f building a federal workforce to 

conduct screening of airline passengers and their checked baggage. See 49 U.S.C. §§ 114(a), 

SA to

ter

 boarding planes. 

2

 TSA classifies the commercial airports in the United States into one of five security ri

categories (X, I, II, III, and IV). In general, category X airports have the largest number

passenger boardings, and category IV airports have the smallest. 

3

The Aviation and Transportation Security Act, Pub. L. No. 107-71, 115 Stat. 59

established TSA and assigned TSA with the responsibility o

44901(a). The act also required that TSA allow commercial airports to apply to T

transition from a federal to a private screener workforce. See § 44920. To support this

effort, TSA created the Screening Partnership Program to allow all commercial airports an

opportunity to apply to TSA for permission to use qualified private screening contractors 

and private screeners. There are currently six airports participating in the Screening 

Partnership Program, including Jackson Hole, Kansas City International, Greater Roches

International, San Francisco International, Sioux Falls Regional, and Tupelo Regional.

4

 Enplanements are the number of airplane passengers

Page 63 GAO-07-299 TSA Staffing Standards
Appendix I: Objectives, Scope, and 

Methodology 

and full time equivalent allocations under the Screening Allocation Model.

We also selected two additional airports in category III based solely on 

their geographic proximity to two of the airports we visited in the larger 

airport categories. All of the nation’s airports in the categories we select

(categories X, I, II, and III) to visit collectively comprise more than 90

percent of TSA’s total TSO allocation nationwide.

Phase 

ed

Table 6: Airports Visited after the Design

Geographic location Airport category

2005 total 

enplanements

2006 

 SAM allocation 

2006 average

 peak wait time

Florida: 

Orlando International X 16,502,499 925.1 16.98

Michigan: 

Detroit Metro Wayne County X 17,433,663 733.9 7.85

Indiana: 

Indianapolis International I 4,211,461 292.1 8.27

California: 

John Wayne I 4,791,100 217.4 17.99

South Carolina: 

Columbia Metropolitan II 725,267 58.9 16.18

Maine:

Portland International II 734,084 101.4 7.49

Georgia: 

Augusta Bush Field MBS III 155,146 24.9 7.22

Michigan: 

Saginaw International III 213,595 21.0 3.08

Source: GAO based on review of TSA data. 

In total, since we selected a limited nonprobability sample of 14 airports, 

the information and results obtained cannot be generalized to all airports 

nationwide. Rather, the results from our airport visits were designed to 

help identify aspects of the Screening Allocation Model that may not be 

adequately addressing unique airport characteristics. Also, on a year-toyear basis, TSA may change the data inputs and assumptions used to 

calculate TSO allocations nationwide and at individual airports. 

In reviewing TSA’s Staffing Allocation Model, we did not (1) review the 

statistical algorithm used in the model, (2) verify the model’s computer 

programming, or (3) run test data through the model. 

Page 64 GAO-07-299 TSA Staffing Standards
Appendix I: Objectives, Scope, and 

Methodology 

More details about the scope and methodology of our work regarding each 

of the objectives are presented in the following sections, respectively.

To determine how TSA ensures its Staffing Allocation Model provides a 

sufficient number of Transportation Security Officers (TSO) to perform 

btain an understanding of how the Staffing Allocation Model works to 

provide the appropriate number of TSO staff at the nation’s airports. We 

terviewed key officials in TSA headquarters responsible for the 

development and implementation of the model about the inputs and 

he model and how these elements are used to determine 

staffing levels. We also reviewed documentation, 

e design and operation of the model.

Additionally, we interviewed Federal Security Directors (FSD) and their 

staff at the 14 airports about how the Staffing Allocation Model considers 

factors unique to their airports in determining the allocation of TSOs to 

perform passenger and baggage screening functions. In addition, we asked 

FSDs and staff about the adequacy of their allocation and their ability to 

make changes to the model input, for their airport, if necessary. During the 

visits to category X, I, and II airports, we also interviewed representatives 

of each airport’s governing authority and one or more of each airport’s 

significant airline operators, to obtain their perspectives on the adequacy

of TSA’s staffing allocations and TSO scheduling practices at the 

respective airports. In addition, we interviewed representatives of two 

airline industry associations—the Air Transport Association and the 

Regional Airline Association—about their perspectives on TSO staffing 

levels at the nation’s commercial airports. 

We also met with TSA headquarters officials to ascertain the methodology 

used in developing the Screening Allocation Model—including the extent 

of input from FSDs and other airport stakeholders—and 

compared/contrasted the model to previous staffing models and methods 

used by TSA for allocating TSOs to the nation’s airports. We interviewed 

these same officials to determine details on the functioning of the 

Screening Allocation Model, the various data inputs and assumptions built 

into the model, how the model uses these factors to determine specific 

TSO staffing at individual airports, and what feedback, if any, is obtained 

from FSDs regarding their allocations. In addition, we reviewed relevant 

documentation from TSA regarding the Screening Allocation Model’s 

assumptions, requirements, and components, along with TSA’s policies 

and procedures guiding the allocation of TSO staff at airport passenger 

Objective One: Use of the 

Staffing Allocation Model 

to Provide a Sufficient 

Number of TSOs to 

Perform Passenger and 

Checked Baggage 

Screening at Each Airport 

and Challenges Faced 

While Implementing the 

Model 

passenger and checked baggage screening at each airport and what 

challenges it has faced while implementing the model, we first sought to 

o

in

assumptions to t

appropriate TSO

provided by these officials, on th

Page 65 GAO-07-299 TSA Staffing Standards
Appendix I: 

Methodology 

Objectives, Scope, and 

Page 66 GAO-07-299 

checkpoints and checked baggage screening areas. We also obtained data

on the changes in nationwide TSO allocations since 2004 and examine

how TSA, using the model, ensures that it has a sufficient number of T

to perform passenger and checked baggage screening. 

We also examined how TSA ensures the model complies with statutory 

requirements—specifically, whether the model (1) provides the necessa

levels of passenger and baggage security, (2) minimizes average passenger

wait times, and (3) ensures that TSA remains in compliance with the 

congressionally mandated full-time-equivalent TSO cap. To that end, we 

interviewed TSA headquarters officials and reviewed Screening Allo

Model-related documentation to ascertain TSA’s approach to monitor

performance of the model. We also analyzed TSA’s airport-specific 

performance data to determine how, if at all, various workforce indica

have chang

d

SOs

ry

cation 

ing

tors

ed since the model was implemented. These indicators include 

passenger wait times, TSO absenteeism rates, TSO attrition rates, TSO 

adm

Na

t the 14 airports, we met with FSDs and other TSA officials to determine 

e

Sta al

SO allocation process. During our discussions with the FSDs, we 

iscussed how well the airport’s allocation, as determined by the model, 

SO

n 

s in

ning areas in order to better understand 

any unique situations or airport characteristics that affect screening 

operations and assessed the impact of these situations on the model’s 

allocation of TSOs to the airport. 

During the visits to the two similar airports in each of categories X, I, and

II, we attempted to determine (1) why one airport received a larger TSO 

under the Screening Allocation Model, (2) reasons for 

he SAM allocations at

overtime usage, TSO injury rates, number of TSOs devoted to

inistrative duties, level of usage of part-time TSOs, and use of the 

tional TSO force.

A

details on the extent to which they participated in the development of th

ffing Allocation Model and their level of input into the model’s annu

T

d

takes into account the unique characteristics of the airport and the T

workforce. These characteristics include airport layout, passenger 

checkpoint configuration, and passenger and baggage screening 

procedures and equipment. We also examined how the Staffing Allocatio

Model addresses changes in air traffic and airport layout, change

security screening procedures, and changes in screening equipment. 

In addition to the discussions with FSDs and other TSA officials, during 

our airport visits we also physically observed the airport’s passenger 

checkpoints and baggage scree

allocation 

differences in passenger wait times, and (3) how t

TSA Staffing Standards
Appendix I: Objectives, Scope, and 

Methodology 

these two airports affected the FSD’s ability to schedule TSOs to pe

required security screening activities.

rform

To determine how TSA deploys its allocation of TSOs at individual airports

and addresses other factors affecting the deployment, we interviewed TSA 

staff at headquarters and at the airports we visited, regarding TSO 

scheduling and workforce-related factors that can affect these efforts. We 

also obtained and reviewed various TSO workforce-related data from TSA 

headquarters pertaining to these factors than can affect TSA’s scheduling 

efforts at individual airports. These data include airport-specific 

information on the number of part-time TSOs, absenteeism rates, attrition,

overtime, workman’s compensation injury claims, and number of TSOs 

being used for operational support. In addition, we interviewed TSA 

headquarters officials, and FSDs at individual airports, about various 

human capital initiatives TSA is implementing to address TSO workforce 

issues (e.g., TSO attrition, lack of sufficient part-time staff, TSO 

absenteeism, injuries, etc.) that affect the deployment of TSOs allocated to

individual airports. 

At the 14 airports we visited, we met with FSDs and other TSA officials to 

determine details on their methods for scheduling TSOs allocated to them

by the model and their use of the model for this purpose. During our 

discussions with the FSDs, we discussed challenges they face in 

scheduling the required number of TSOs to perform screening functions. 

These challenges include airport layout and associated physical 

infrastructure limitations, type of passenger and baggage screening 

procedures employed and type of equipment available, number and mix of 

available full-time/part-time TSOs, number of TSOs unavailable for work 

(including those on leave, absent, injured, in training, or performing 

administrative duties), and experience level of TSOs. We also examined 

how each airport’s scheduling operation addresses changes in air traffic 

5

and airport layout, changes in security screening procedures, and changes

in screening equipment. 

We also analyzed certain TSA airport-specific performance data to 

determine how these factors impact FSDs’ ability to effectively schedule 

 

Objective Two: TSA’s 

Deployment of Its TSO 

Allocation at Individual 

Airports and Factors That 

Impact the Allocation 

Model’s Effectiveness in 

Helping TSA Accomplish 

This Deployment 

5

 We excluded category IV airports from our study because they make up less than 3 

percent of TSOs allocated nationwide under the SAM and passenger boardings at these 

airports are much more limited and sporadic. 

Page 67 GAO-07-299 TSA Staffing Standards
Appendix I: Objectives, Scope, and 

Methodology 

their TSO allocation. Finally, we interviewed TSA airport and human 

capital officials to determine workforce actions TSA has taken to improve 

or enhance the Screening Allocation Model’s ability to effectively allocate

TSOs to the nation’s airports and what other efforts, if any, TSA has 

underway to enhance its ability to deploy TSOs—specifically with respect 

to the indicators noted above. 

In addressing our objectives, we obtained the following data from TSA: 

• Staffing by airport, in full-time equivalents, as of September 30, 2006. 

• TSO staffing allocation, by airport, for fiscal years 2004, 2005, and 2006.

• TSO full-time and part-time full-time equivalents levels for fiscal years 

2004, 2005, and 2006. 

• TSO absenteeism for fiscal years 2004, 2005, and 2006. 

• Workman’s compensation historical claims activity for calendar years 

2004, 2005, and first half of 2006. 

• TSO attrition data for fiscal years 2004, 2005, and 2006. 

• TSO overtime rates for fiscal years 2004, 2005, and 2006. 

• Number and percentage of TSOs used for operational support for 

2-week period ending September 30, 2006. 

• Deployment of the National Screening Force TSOs as of 

October 10, 2006. 

• Airport passenger wait times for fiscal years 2004, 2005, and 2006. 

We discussed the sources of the data with the appropriate TSA officials 

and obtained written responses to questions about TSA data quality 

control efforts for several of these data sets. We determined that the data

for all were sufficiently reliable for the purposes of this report. 

We d January 2006 through January 2007 in 

acco a ccepted government auditin standards. 

Data Reliability 

con ucted our work from

rd nce with generally a g

Page 68 GAO-07-299 TSA Staffing Standards
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

The Aviation and Transportation Security Act, enacted in November 2001,

significantly changed how passenger and checked baggage screening is 

conducted in the United States.1

 ATSA removed screening responsibility 

from air carriers and the contractors who conducted screening for them, 

and placed this responsibility with TSA. As a result, TSA hired and 

deployed approximately 55,000 federal passenger and baggage 

Transportation Security Officers (TSO) (formerly known as screeners) to 

more than 400 airports nationwide. This initial deployment was based on 

input from a contract consultant and the number of private sector 

screeners that had been in place prior to TSA. After this initial roll-out of 

TSOs, TSA developed a demand-driven staffing model called the “GRA” 

model in order to improve screening operations and make them more 

efficient. To derive a TSO staffing allocation for each airport, the GRA 

model used flight schedules, load factors2

 and connecting flight data, 

passenger arrival distribution curves, and the number of passenger 

baggage. However, according to TSA, the GRA model did not provide 

flexibility to react to dynamic changes in the transportation industry. An 

initial run of the GRA model in 2003 called for an overall staffing level of 

49,600 despite a congressionally imposed 45,000 full-time-equivalent cap 

on the number of TSOs TSA could hire. As a result, TSA had to impose a 

7 percent TSO reduction across the board to comply with the 

congressional cap by the end of the year. TSA decided it needed to 

improve its existing demand-driven staffing model—the GRA model—to

create a more dynamic model that takes into account information about 

each airport’s configuration,3

 as well as assumptions about passenger and 

baggage processing. 

TSA developed its new model, the Staffing Allocation Model (SAM), with 

the assistance of a contractor, Regal Decisions (the model was originally 

called the “Regal” model). As part of the contract requirements, Regal staff

and TSA industrial engineers visited airports and met with their Federal 

Security Directors (FSD) to collect baseline information such as number 

of lanes, and number of checked baggage processing nodes, along with 

unique characte uration) of the airports. FSDs had 

some input (mostly verification of th c to their 

 

Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

TSA’s Development of 

Its Staffing Allocation 

Model 

ristics (physical config

e model input data specifi

 1

 Pub. L. No. 107-71, 115 Stat. 597 (2001). 

2

 The percentage of seats filled on a plane. For example, a plane with a load factor of 0.831 

has 8 p

3

 An airport’s configuration entails the layout, design, and number of its checked baggage 

screening areas and passenger screening checkpoints and lanes.

3.1 ercent of its seats filled.

Page 69 GAO-07-299 TSA Staffing Standards
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

airports) into the process, but were not directly involved in creating the 

fing

07

erent components. The 

first is the “GRA” flight data, which provides information to the model on

chedules and passenger and baggage volume. These data are fed 

into the “Regal” software (from Regal Decision Systems), which is a 

simulation model that replicates each airpor nfiguration and 

screening process. Finally, the “Sabre” software is a scheduling tool that 

takes the Regal output, expressed in numbers of TSOs needed to staff 

security checkpoints in 5-minute increments during the day, and produces 

an FTE requirement and corresponding TSO work schedules for each 

airport. Below is a detailed description of the three components that 

combine to make up TSA’s Staffing Allocation Model. 

 

model.4

 Overall, it took Regal and TSA almost a year to get the new 

Staffing Allocation Model stabilized and ready for initial roll-out. TSA 

obtained data for,5

 developed, and began deploying the model for testing in 

the summer of 2004 and first used it for the fiscal year 2005 TSO staf

allocation for the nation’s airports. The latest TSO staffing numbers based 

on the model (for fiscal year 2006) were sent out to the field in October 

2005. TSA was in the process of developing allocations for fiscal year 20

at the time of our report. 

The Staffing Allocation Model consists of three diff

TSA Staffing Standards

flight s

t’s co

 

l.

4

FSDs we interviewed had mixed views on the extent to which they were provided an

opportunity to provide input to th nitial development of the staffing allocation mode

Nine of the 14 FSDs we interviewed stated that they provid d little, if any, input to the 

Staffing Allocation Model’s ntal assumptions a id not know how their 

allocations were derived. H 10 FSDs said TSA uarters did give them an

opportunity to provide input specifically on their airports’ configuration. TSA officials

responsible for the Staffing Allocation Model acknowledged that all FSDs were not directly 

involved in creating the model. Officials stated that industrial engineers were responsible 

for visiting the airports to w y are assigned and ting with FSDs, or their 

designated staff member, to ormation a screening operations and any

unique aspects of their airports. 

5

 During this period, TSA officials at individual airports provided data input to the model

regarding their airports’ profiles—including number of checkpoints, number of lanes, and

number of checked baggage processing nodes. 

Staffing Allocation 

e i

e

fundame

owever,

nd d

headq

hich the

 obtain basic inf

mee

bout

Model Components 

Page 70 GAO-07-299 
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

The GRA flight data uses historical data6 to determine screening demand at

each airport. These historical data include baggage volume, flight and 

passenger distribution curves, size/type of aircraft, and load factors. The 

GRA firm obtains these data mainly from the various airport authorities 

and from published sources such as the Official Airlines Guide. The 

guide’s flight schedules are provided to the airports 60-90 days in advance. 

This allows airports enough time to react to potential changes in their 

passenger flow, and for the FSDs to make any needed changes to the flight

schedules listed in the model, so as to account for last minute scheduling

changes or added flights that were not originally published in the guide.

The updated flight schedules and passenger loads (which represent the

screening demand) from the GRA model serve as the input for the Regal

software, which determines the number of open lanes and the amount of

baggage equipment needed.

The annual staffing allocation for each airport is based on the peak month

demand level (derived by reviewing historical flight and 

passenger/baggage load data available from the GRA software) input into 

the Regal software, to ith data on air configurations and 

assumptions about passenger and baggage processing (that were not a 

part of the old GRA demand-driven model). The Regal software uses these 

input data to simulate the actual flow of passengers and baggage through 

the airport. The final o each airport’s requirements (in number

TSO staff for all passenger lanes and baggage pods, expressed in 5 minute 

increments throughout the day)—is determined based on the various 

assumptions outlined in table 7 and discussed as follows: 

• Nonpassenger screening demand

TSA Staffing Standards

gether w port

utput— of

—This is the additional demand for 

personnel screening checkpoints created by nonpassengers (e.g., 

airline crews, concession staff, and airport vendors). Based on 

discussions with TSA leadership and estim s by industrial engine

the model constant for nonpassenger screening demand was set at 4 

percent of passenger lane volume. 

• Passenger processing wait time

ate ers,

—This is the amount of time passengers 

have to wait to undergo reening at the security checkpoint. The 

 

sc

 

GRA Flight Data 

Regal Software

6

 The GRA consulting firm engages in an ongoing data collection effort. It gathers future 

flight schedules, historical passenger loads, and connecting percentages—all of which can

be adjusted with appropriate approval. Passenger loads and baggage counts are purely

historical data that can’t be routinely adjusted. 

Page 71 GAO-07-299 
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

model sets a threshold of a 10-minute wait before opening additional

lanes, if available, based on passenger volumes. 

• Peak month screening demand—TSA derives the Staffing Allocation 

Model’s allocations based on originating passenger load factors for the 

ad data for each 

month in the airport’s year. According to TSA industrial engineers, 

demand data are not reported by the airlines (and, is therefore, not 

y

e

r

g

e

ned.

y

s

ssenger 

leave

is

staffing capacity to respond to 

85th percentile day of each airport’s peak month. In determining the 

85th percentile day, TSA must first determine each airport’s peak 

month by reviewing historical monthly passenger lo

selection of the peak month is based on the average demand day 

(based on passenger load) for each month with the peak month being

the month with the highest average demand day. Since daily screening 

available) TSA must approximate each month’s average demand day b

dividing the monthly passenger load data by the number of days in th

month. This assumption is linked to TSA’s 10-minute wait time goal fo

processing passengers and baggage through security. That is, accordin

to TSA industrial engineers, basing the Staffing Allocation Model on th

average peak demand day is intended to ensure that, on an annual 

basis, 85 percent or more of the total passengers screened in U.S. 

airports will not have to wait more than 10 minutes to be scree

Further, based on TSA’s analysis, basing the model on this level of

demand may result in TSA taking longer than 10 minutes to screen 

passengers during 7 percent of an airport’s days during the year.

According to TSA, these 25 to 30 days are typically the exceptionall

high travel days such as the days before the Thanksgiving and

Christmas holidays. Conversely, for purposes of the annual allocation, 

TSA industrial engineers added that basing the model’s demand level

on the average peak demand day may result in TSA screening 

passengers in 10 minutes or less during 93 percent of the airport’s day

during the year (approximately 335 to 340 travel days over the airport’s 

year). Lastly, when determining the annual allocation, TSA officials run

the model on a representative week during the peak month.7

By basing airports’ staffing allocations on their peak month pa

volume, TSA intends to ensure that airports will have some staff to 

accommodate nonscreening activities such as training and annual

during off-peak periods. In addition, the peak month-based allocation

intended to provide airports with excess

 7

 TSA officials stated that, for the annual allocation run, they must run the model based on 

a full week (as if trying to schedule for that week) since it is not practi

based on only 1 day. 

cal to run the model 

Page 72 GAO-07-299 TSA Staffing Standards
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

unforeseen events such as changes in flight schedules, injuries, and 

sick leave. In addition to nonpassenger screening demand, pass

processing wait time, and the calculation of demand, the following 

assumptions were included in the fiscal year 2007 model: 

•

enger

Line item full-time-equivalent allocation for TSO time paid but not 

worked—In fiscal year 2007, TSA, for the first time, provided a sep

line item allocation for the various categories of TSO time paid not 

worked. These categories include vacation, sick, comp, injury, and 

military leave. Prior to fiscal year 2007, TSO time paid not worked was 

indirectly accounted for within the peak month screening demand/85

percentile day assumption. 

arate

th

• Part-time staff—TSA sets the SAM to run at a staffing mix of full-time 

and part-time TSO full-time equivalents based on each airport’s 

individual part-time to full-time TSO ratio. Prior to fiscal year 2007, TSA

assumed the same part-time goal for all category X, I, and II airports—

regardless of their actual ratios. 

• Passenger checkpoint throughput—The passenger checkpoint 

throughput is the number of passengers that are processed per security 

checkpoint lane, per hour. The model assumes this to be 200. 

• Checked baggage processing rates—The checked baggage processing 

rate is the number of bags that various types of screening equipment 

will process per hour. Table 7 shows baggage processing rates based

on type of screening equipment and whether the baggage sc

system is in-line

reening 

Baggage staffing requirements

8

 or stand-alone.9

• —This is the number of TSO FTEs 

required to adequately staff screening equipment. As with checked 

baggage processing rates, baggage staffing requirements vary by 

screening equipment, whether the equipment is stand-alone or inline, 

and by airport category.

• Staffing per lane by airport category—The model allocates staffing by

airport category and by lane type. A standard checkpoint lane is

 

a lane

 d out 8

 A bag screening methodology that employs the automated movement of a bag in an

of an explosive detection system machine.

9

 A bag screening methodology that employs a manual (as opposed to an automated) 

movement of bag in and out of an explosive detection system machine. 

Page 73 GAO-07-299 TSA Staffing Standards
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

that processes only passengers who are not selectees (i.e., those 

passengers selected for more intense screening). An integrated 

checkpoint lane is a lane that processes both standard passengers a

selectees. A dedicated checkpo

nd

int lane is a lane that processes only 

passengers who are selectees. 

• Standard alarm rates—The model assumes specific rates for alarms o

screening equipment used at both passenger checkpoints and

check areas. The model also assumes a selectee rate for passenger 

checkpoints.

n

baggage

Table 7: Staffing Allocation Model Assumptions for Fiscal Year 2007

Assumption Value or description

Nonpassenger demand (percent) 4

Passenger processing time (in minutes) 10

Peak month demand Based on 95th percentile day 

Annual leave allocation 14.5

Sick leave 3.7

Comp time 0.4

Injury time off 0.2

Full-time-equivalent credits for time paid

worked (in percent) 

not 

Military leave 0.1

Full-time-equivalent credit for training 

(percent) 

 2.0

Full-time-equivalent credit for collateral dutie

(percent) 

s 5.0

Part-time staff full time-equivalent level

(percent) 

Variable by airport

Passenger checkpoint throughput (passengers 

per lane, per hour) 

 200

Passenger checkpoint throughput for ETP 

machine 

 175

EDS Equipment 

Type

Stand-Alone In-Line

Invision CTX 9000 160 350

Invision CTX 5500 200 210

Invision CTX 2500 115 N/A

Examiner 6000 L3 160 350

Checked baggage processing rates (bags pe

machine, per hour) 

CT80 80 N/A

r 

Page 74 GAO-07-299 TSA Staffing Standards
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

Page 75 GAO-07-299 

Assumption Value or description

Airport category Equipment type Stand-alone In-line In-line (with OSR)

X, I, II, & III EDS 2 0.625 0.625

(ETD only) ETD 1.25 1.25 1.25

Baggage staffing 

requirementsa

IV

Airport category Staff per lane Per lane selecteebLand type credit

Standard 4.25 0.9

Integrated 4.25 0.9

X, I, & II 

Dedicated 2.5 0.9

III All lanes 3.5 0

Staffing per lane by 

airport category

a

IV All lanes 2.0 0

Standard 

passenger 

Checkpoint Staffing sufficient up to 6 percent selectee alarm 

passenger 

Selectee Staffing sufficient up to 6 percent selectee alarm 

Standard alarm rates 

Baggage EDS Staffing sufficient up to 15 percent alarm 

Source: TSA. 

Legend: EDS = explosive detection system; ETD = explosive trace detection; ETP = explosive trace 

portal; OSR = on-screen resolution; N/A = not available. 

a

Staffing is number of TSO staff per piece of equipment or passenger checkpoint lane. 

e is a passenger who meets certain criteria based on the Computer Assisted Passenger bA selecte

Preaddition to the model assumptions shown in table 7, the Regal software 

s or decreases),

ariable arrival patterns, and each airport’s configuration including making

e t from the GRA software, when TSA 

irp

r of TSOs

va

to

ha data if it is believed they

e

b

f

ool has three features—Staff Admin, Staff Manager, and Staff 

Plan. (TSA did not purchase the Staff Manager component.) Staff Admin 

Sabre Software 

Screening System or some other TSA-approved process and is, therefore, subject to more 

intense screening such as wanding and bag checks. 

In

also incorporates adjustments to flight schedules (increase

v

any allowances for projected expansions to the airport’s configuration. 

R gal also determines, based on inpu

a ort officials need to open more passenger processing lanes in response 

to increased passenger flow (not to exceed the total numbe

a ilable). An individual airport FSD cannot change either the model 

assumptions or the baseline configuration for their assigned airport

without TSA headquarters approval, but can petition TSA headquarters

c nge assumptions and baseline configuration

ar not reflective of his/her airport. 

Sa re Airline Solutions, Inc., provides the commercial, off-the-shelf 

so tware for the staffing allocation model’s scheduling tool. The Sabre 

scheduling t

TSA Staffing Standards
Appendix II: Development and Description of 

TSA’s Staffing Allocation Model 

rosters an airport’s employee group in a database (shifts, schedules, 

personal information, training, etc.) while Staff Plan recommends a m

full-time and part-time TSOs and generates a daily work schedule based on

the Regal software’s staffing requirement output. Sabre takes th

ix of

e Regal

output and converts it into an full-time-equivalent figure and it determines 

, I,

and II airports. 

TSA uses the Staffing Allocation Model in three different ways—first, it is 

run once a year to determine the staffing allocation for all airports (annual 

allocation run). Second, it is run at other times to perform capacity 

analysis for both lanes required and number and types of baggage

equipment required. Third, it is run at other times of the year where 

airports can tweak certain aspects of the model for scheduling runs 

without approval from TSA headquarters—for example, to conduct “whatif” scheduling scenarios by changing different inputs, such as passenger 

flow, or flight schedules. However, they cannot do so for an annual 

allocation run unless TSA headquarters grants approval to change an 

assumption for a specific airport. The baseline for an annual allocation run 

always stays the same and cannot be changed by an airport without TSA 

headquarters approval. TSA models each airport according to its unique 

configuration—that is, no two airports are modeled the same because no

two airports look the same (nor do they have the same airline traffic 

profile). FSDs and their staffs typically meet with airline carriers on a 

continuing basis to obtain updated flight schedules. The scheduling runs to 

determine TSO schedules incorporate these updated flight schedules 

whereas, the fiscal runs to determine overall full-time-equivalent 

allocation, using peak month passenger volumes from historical flight 

data. If the historical flight schedule used for an annual allocation run is 

significantly different from current flight schedules at an airport (e.g., a 

new airline carrier joins the airport), the FSD can submit an appeal to TSA 

headquarters to re-run the model using the current flight schedule in order 

to obtain a more accurate staffing allocation for his or her airport. (This 

has been done on an annual basis or when a significant change in the

airport’s flight schedule occurs.) Unlike for annual allocation runs, 

updated flight schedules are used more frequently for scheduling runs at

the local airports without headquarters intervention. 

The Staffing Allocation Model can be adjusted to account for the 

uniqueness of a particular airport’s security checkpoints and airline traffic 

patterns. However, FSDs are responsible for ensuring that all data 

TSA’s Use of the 

scheduling plans based on that figure (if the airport uses Sabre for 

scheduling) using the 80/20 full-time/part-time TSO mix for category X

Staffing Allocation 

Model 

Page 76 GAO-07-299 TSA Staffing Standards
Appendix II: De

TSA

velopment and Description of 

’s Staffing Allocation Model 

Page 77 GAO-07-299 

elements and assumptions are accurate for their airports and bringing to 

headquarters’ attention any factors that should be reviewed to determine

changes to the model for their airports may be appropriate. 

if 

TSA Staffing Standards
Appendix III: Comments from the Department 

of Homeland Security

Page 78 GAO-07-299 TSA Staffi TSA Staffing Standards

Appendix III: Comments from the Department 

of Homeland Security

Page 78 GAO-07-299 

Appendix III: Comments from the 

Department of Homeland Security 
Appendix III: Comments from the Department 

of Homeland Security

Page 79 GAO-07-299 TSA Staffing Standards
Appendix III: Comments from the Department 

of Homeland Security

Page 80 GAO-07-299 TSA Staffing Standards
Appendix III: Comments from the Department 

of Homeland Security

Page 81 GAO-07-299 TSA Staffing Standards
Appendix III: Comments from the Department 

of Homeland Security

Page 82 GAO-07-299 TSA Staffing Standards
Appendix III: Comments from the Department 

of Homeland Security

Page 83 GAO-07-299 TSA Staffing Standards
Appendix IV: GAO Contact and Staff 

Acknowledgments 

Brian J. Lepore (202) 512-4523 or leporeb@gao.gov. 

In addition to those named above, Maria Strudwick, Assistant Director; 

David Alexander; Richard Ascarate; Philip Caramia; Kathryn Godfrey; 

Michael Harmond; Thomas Lombardi; Enemencio Sanchez; Edith S

Pamela Valentine; Vaughn Williams; and Greg Wilmoth made key 

contributions to

ohna;

this report.

Appendix IV: GAO Contact and Staff 

Acknowledgments 

GAO Contact 

Acknowledgments 

Page 84 GAO-07-299 TSA Staffing Standards
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Page 85 GAO-07-299 TSA Staffing Standards
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Page 86 GAO-07-299 TSA Staffing Standards
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July 25, 2002.

Aviation Security: Information Concerning the Arming of Commercial

Pilots. GAO-02-822R. Washington, D.C.: June 28, 2002. 

Aviation Security: Vulnerabilities in, and Alternatives for, Preboard 

Screening Security Operations. GAO-01-1171T. Washington, D.C.: 

September 25, 2001. 

Aviation Security: Weaknesses in Airport Security and Options for 

Assigning Screening Responsibilities. GAO-01-1165T. Washington, D.C.: 

September 21, 2001. 

Homeland Security: A Framework for Addressing the Nation’s 

Efforts. GAO-01-1158T. Washington, D.C.: September 21, 2001. 

Aviation Security: Terrorist Acts Demonstrate Urgent Need to Improve 

Security at the Nation’s Airports. GAO-01-1162T. Washington, D.C.: 

September 20, 2001. 

Page 89 GAO-07-299 TSA Staffing Standards
Related GAO Products 

Page 90 GAO-07-299 TSA Staffing Standards

Aviation Security: Terrorist Acts Illustrate Severe Weaknesses in 

Aviation Security. GAO-01-1166T. Washington, D.C.: September 20, 2001. 

(440474) 
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