**APPENDIX A**

**DEFINITIONS OF ESTIMATING TERMINOLOGY**

**APPENDIX A**

**DEFINITIONS OF ESTIMATING TERMINOLOGY**

**[Algorithmic Models]{.underline}** - (also known as Parametric models)
produce a cost estimate using one or more mathematical algorithms using
a number of variables considered to be the major cost drivers. These
models estimate effort or cost based primarily on the Hardware/Software
size, and other productivity factors known as cost driver attributes.

**[Analogy]{.underline}** - A method of estimating developed on the
basis of similarities between two or more programs, systems, items, etc.

**[Analogy Models]{.underline}** - use a method of estimating that
involves comparing a proposed project with one or more similar and
completed projects where costs and schedules are known. Then,
extrapolating from the actual costs of completed projects, the model(s)
estimates the cost of a proposed project.

**[Analometric]{.underline}** - A recent term meaning a method of
combining the analogy and parametric estimating methods to form a cost
estimate when only 2 relevant data points are available. It is usually
combined with the \"D\" Factor to adjust (up or down) complexity from
the 2 point CER regression line.

**[Analysis]{.underline}** - decision making context involving time
horizons extending into the future. A concrete set of specifications are
not usually available. There could be many major uncertainties, and a
wide range of alternatives, each having several configurations. Analysis
is usually concerned with new equipment proposals and new methods of
operation of systems never produced before. Analysis Objectives are to
find significant differences in resource requirements among
alternatives; and, how will resource requirements for any alternative
change as key configuration characteristics vary over their relevant
ranges. It is often a \"sensitivity\" type of investigation.

**[Analysis]{.underline}** (NES Dictionary) - a systematic approach to
problem solving. Complex problems are simplified by separating them into
more understandable elements.

**[Annual Change Traffic (ACT)]{.underline}** - the fraction of a
software product\'s source instructions which undergoes change during a
year, either through addition or modification. The ACT is the quantity
used to determine the product size for software maintenance effort
estimation.

**[Anomalies]{.underline}** - variances in cost related data caused by
an unusual event(s) not expected to recur in the future.

**[As Spent Dollars]{.underline}** - the cost, in real year dollars, of
a project recorded as the dollars were spent without normalization for
inflation.

**[Audit]{.underline}** - the systematic examination of records and
documents and the securing of evidence by confirmation, physical
inspection, or examination.

**[Audit Trail]{.underline}** - information allowing the data being used
in an estimate to be tracked back to the original source for
verification.

**[Benefit]{.underline}** (NES Dictionary) - Result(s) attained in terms
of the goal or objective rather than in terms of output.

**[Benefit Cost Analysis]{.underline}** (NES Dictionary) - an analytical
approach to solving problems of choice. It requires: (a) the definition
of objectives; (b) identification of alternative ways of achieving each
objective; and (c) the identification for each objective or alternative
which yields the required level of benefits at the lowest cost. It is
often referred to as cost-effectiveness analysis when the benefits of
the alternatives cannot be quantified in terms of dollars.

**[Benefits]{.underline}** (NES Dictionary) - advantages which may be
quantifiable or non-quantifiable. For example, lowest cost is a benefit,
so is the best accuracy and longest range.

**[Bottom-Up Models]{.underline}** - use a method of estimation that
estimates each component of the project separately, and the results are
combined (\"Rolled Up\") to produce an estimate of the entire project.

**[Calibration]{.underline}** - in terms of a cost model, a technique
used to allow application of a general model to a specific set of data.
This is accomplished by calculating adjustment factor(s) to compensate
for differences between the referenced historical costs and the costs
predicted by the cost model using default values.

**[Computer-Aided Software Engineering: CASE]{.underline}** - identifies
a sector of the computer software industry concerned with producing
software development environments and tools. The main components of a
CASE product are individual tools which aid the software developer or
project manager during one or more phases of software development (or
maintenance). Other features are a common user interface;
interoperability of tools; and a repository or encyclopedia to provide a
common tool base and central project database. CASE may also provide for
code generation.

**[Configuration Item]{.underline}** - hardware or software, or an
aggregate of both, which is designated by the project configuration
manager (or contracting agency) for configuration management.

**[Configuration Management]{.underline}** - a discipline applying
technical and administrative controls to (1) identification and
documentation of physical and functional characteristics of
configuration items; (2) any changes to characteristics of those
configuration items; and (3) recording and reporting of change
processing and implementation of the system.

**[Constant Dollars]{.underline}** - Computed values which remove the
effect of price changes over time (inflation). An estimate is said to be
in constant dollars if costs for all work are adjusted to reflect the
level of prices of a base year.

**[Contract Work Breakdown Structure]{.underline}** - Contract work
breakdown structure is defined as the complete work breakdown structure
for a contract, i.e., the DoD approved work breakdown structure for
reporting purposes and its discretionary extension to the lower levels
by the contractor, in accordance with this standard and the contract
work statement.

**[Cost]{.underline}** (Fisher) - \"Economic costs\" are benefits lost.
It is for this reason that economic costs are often referred to as
\"alternative costs\" or \"opportunity costs.\" It is in alternatives,
it is in foregone opportunities, that the real meaning of \"cost\" must
always be found. The only reason you hesitate to spend a dollar,
incidentally, is because of the alternative things that it could buy.
Some use the word \"cost\" when referring to resources. Cost of
something is measured by the resources used to attain it. Cost of
attaining an objective at some point in time is measured by the
resources not available for use in attaining alternative objectives.
Costs are a measure of other defense capabilities foregone. Money cost
is not necessarily the same as economic cost. \"Economic cost\" implies
the use of resources - manpower, raw materials, etc. Dollars are used
merely as a convenient common denominator for aggregating numerous
heterogeneous physical quantities into meaningful \"packages\" for
purposes of analysis and decision mating.

**[Cost]{.underline}** (NES Dictionary) - the amount paid or payable for
the acquisition of materials, property, or services. In contract and
proposal usage, denotes dollars and amounts exclusive of fee or profit.
Also used with descriptive adjectives such as "acquisition cost,\" or
\"product cost,\" etc. Although dollars normally are used as the unit of
measure, the broad definition of cost equates to economic resources,
i.e., manpower, equipment, real facilities, supplies, and all other
resources necessary for weapon, project, program, or agency support
systems and activities.

**[Cost Analysis]{.underline}** (NES Dictionary) - the accumulation and
analysis of actual costs, statistical data, and other information on
current and completed contracts or groups of contracts (programs). Cost
analysis also includes the extrapolation of these cost data to
completion, comparisons and analyses of these data, and cost
extrapolations on a current contract with the cost data in the contract
value for reports to customers, program and functional managers, and
price estimators. In the procurement organizations of the Department of
Defense, cost analysis is the review and evaluation of a contractor\'s
cost or pricing data and of the judgmental factors applied projecting
from the data to the estimated costs, in order to form an opinion on the
degree to which the contractor\'s proposed costs represent what
performance of the contract should cost, assuming reasonable economy and
efficiency.

**[Cost Analysis]{.underline}** (Large) - the primary purpose of cost
analysis is comparison - to provide estimates of the comparative or
relative costs of competing systems, not to forecast precisely accurate
costs suitable for budget administration. In this context consistency of
method is just as important, perhaps more so, as accuracy in some
absolute sense. In comparing the costs of military systems, we prefer to
speak of \"cost analysis\" rather than \"cost estimation,\" because the
identification of the appropriate elements of cost \-- the analytical
breakdown of many complex interrelated activities and equipment \-- is
so important a part of the method. Weapon system cost analysis is much
more than an estimate of the cost of the weapon itself. Weapon
procurement costs may be relatively small compared to other necessary
costs, such as base facilities, training of personnel, and operating
expenses; and these other costs may vary greatly from system to system.

**[Cost Benefit Analysis]{.underline}** (NES Dictionary) - a technique
for assessing the range of costs and benefits associated with a given
option, usually to determine feasibility. Costs are generally in
monetary terms.

**[Cost Driver Attributes]{.underline}** - productivity factors in the
software product development process that include software product
attributes, computer attributes, personnel attributes, and project
attributes.

**[Cost Drivers]{.underline}** - The controllable system design or
planning characteristics that have a predominant effect on the system\'s
costs. Those few items, using Pareto\'s law, that have the most
significant cost impact.

**[Cost Effectiveness]{.underline}** (NES Dictionary) - the measure of
the benefits to be derived from a system with cost as a primary or one
of the primary measures.

**[Cost Effectiveness Analysis]{.underline}** (NES Dictionary) - a
method for examining alternative means of accomplishing a desired
military objective/mission for the purpose of selecting weapons and
forces which will provide the greatest military effectiveness for the
cost.

**[Cost Estimating]{.underline}** (Fisher) - \"making an estimate\" of
the cost of something implies taking a rather detailed set of
specifications and \"pricing them out.\"

**[Cost Estimating]{.underline}** (NES Dictionary) - cost and price
estimating is defined as the art of predetermining the lowest realistic
cost and price of an item or activity which assure a normal profit.

**[Cost Estimating Relationship]{.underline}** - An algorithm relating
the cost of an element to physical or functional characteristics of that
cost element or a separate cost element; or relating the cost of one
cost element to the cost of another element.

**[Cost Estimating Relationships: CER]{.underline}** - a mathematical
expression which describes, for predicative purposes, the cost of an
item or activity as a function of one or more independent variables.

**[Cost Factor]{.underline}** - a brief arithmetic expression wherein
cost is determined by the application of a factor as a proportion.

**[Cost Model]{.underline}** - an estimating tool consisting of one or
more cost estimating relationships, estimating methodologies, or
estimating techniques used to predict the cost of a system or one of its
lower level elements.

**[Cost/Schedule Control System Criteria: C/SCSC]{.underline}** - a set
of criteria specified by the Federal Government for reporting project
schedule and financial information.

**[Current Dollars]{.underline}** - Level of costs in the year actual
cost will be incurred. When prior costs are stated in current dollars,
the figures given are the actual amounts paid. When future costs are
stated in current dollars, the figures given are the actual amounts
expected to be paid including any amount due to future price changes.

**[Deflators]{.underline}** - The de-escalation factors used to adjust
current cost/price to an earlier base year for comparison purposes. A
deflator is the inverse of an escalator.

**[Delivered Source Instructions: DSIs]{.underline}** - the number of
source lines of code developed by the project. The number of DSIs is the
primary input to many software cost estimating tools. The term
*DELIVERED* is generally meant to exclude non-delivered support software
such as test drivers. The term *SOURCE INSTRUCTIONS* includes all
program instructions created by project personnel and proceed into
machine code by some combination of preprocessors, compilers, and
assemblers. It excludes comments and unmodified utility software. It
includes job control language, format statements, and data declarations.

**[Delphi Technique]{.underline}** - a group forecasting technique,
generally used for future events such as technological developments,
that uses estimates from experts and feedback summaries of these
estimates for additional estimates by these experts until a reasonable
consensus occurs. It has been used in various software cost-estimating
activities, including estimation of factors influencing software costs.

**[Detail Estimating: Grass Roots, Bottom-Up]{.underline}** - The
logical buildup of estimated hours and material by use of blue-prints,
production planning tickets, or other data whereby each operation is
assigned a time value.

**[Design to Cost: DTC]{.underline}** - An acquisition management
technique to achieve defense system designs that meet stated cost
requirements. Cost is addressed on a continuing basis as part of a
system\'s development and production process. The technique embodies
early establishment of realistic but rigorous cost objectives, goals,
and olds and thresholds and a determined effort to achieve them. Cost,
as a key design parameter, is addressed on a continuing basis and as an
inherent part of the development and production process. Cost goals are
established early in the development phase, which reflect the best
balance among life cycle cost, acceptable performance and schedule.

**[DOD-STD-2167A/498]{.underline}** - a US Department of Defense
standard that specifies the overall process for the development and
documentation of mission-critical software systems. DOD-STD-2167A/498
has direct connections to five other standards that are not software
specific. These five standards are as follows:

MIL-STD-1521 Technical Reviews and Audit for Systems, Equipments, and
Computer Software

MIL-STD-480 Configuration Control - Engineering Changes, Deviations, and
Waivers

MIL-STD-481 Configuration Control - Engineering Changes, Deviations, and
Waivers (Short Form)

MIL-STD-490 Specification Practices

MIL-STD-499 Engineering Management

MIL-STD-480 and 481 have been superseded by MIL-STD-973. MIL-STD-973
consolidates several earlier standards for configuration management and
resolves inconsistencies and ambiguities that existed between them. When
DOD-STD-2167A/498 is applied to contract, appropriate tailoring
instructions should be included to indicate that the contract is to
comply with the more recent MIL-STD-973.

**[Domain]{.underline}** - a specific phase or area of the software life
cycle in which a developer works. Domains define developers and users
areas of responsibility and the scope of possible relationships between
products. The work can be organized by domains such as Software
Engineering Environments, Documentation, Project Management, etc.

**[DTC Goals]{.underline}** - A cost bogey, in constant dollars, based
upon a specified production quantity and rate, established early during
system development as a management objective and design parameter for
subsequent phases of the acquisition cycle. (see DTC Target).

**[DTC Parameter]{.underline}** - Approved measurable values for
selected cost elements established during system development as design
considerations and management objectives for subsequent life cycle
phases. A DTC parameter may be an objective, goal, or threshold. Values
will be expressed it constant dollars, resources required, or other
measurable factor(s) that influences costs.

**[DTC Targets]{.underline}** - Approved DTC parameters divided into
smaller. identifiable tasks or areas of responsibility that serve as
requisites for contractors or government activities.

**[DTC Threshold]{.underline}** - Costs or values that, if exceeded,
will cause a program review.

**[Economics]{.underline}** (Hitch and McRean) - economics is concerned
with allocating resources. Economizing always means trying to make the
most efficient use of the resources available.

**[Economics Analysis]{.underline}** (Hitch and McRean) - economic
analysis - ranging from just straight thinking about alternative courses
of action to systematic quantitative comparisons, to identify or achieve
near \"optimal\" solutions.

**[Economic Analysis]{.underline}** (DoDI 7041.3) - a systematic
approach to the problem of choosing how to employ scarce resources and
an investigation of the full implications of achieving a given objective
in the most efficient and effective manner.

**[Economic Analysis]{.underline}** (NES Dictionary) - a systematic
approach to a given problem, designed to assist the manager in solving a
problem of choice. The full problem is investigated; objectives and
alternatives are searched out and compared in light of their benefits
and costs through the use of an appropriate analytical framework. Often
used to determine the best use of scarce resources.

**[Effectiveness]{.underline}** (DoDI 7041.3) - the performance or
output received from an approach or program.

**[Effort Adjustment Factor: EAF]{.underline}** - a term used in COCOMO
to calculate the cost driver attribute\'s effect on the project. It is
the product of the effort multipliers corresponding to each of the cost
drivers for the project.

**[Embedded Node]{.underline}** - a term used by COCOMO to describe a
project development that is characterized by tight, inflexible
constraints and interface requirements. The product must operate within
(is embedded in) a strongly coupled complex of hardware, software,
regulations and operational procedures. An embedded mode project will
require a great deal of innovation. An example would be a real-time
system with timing constraints and customized hardware.

**[Equivalent Units]{.underline}** - the number, or fraction, of
completed units at a given time.

**[Estimating]{.underline}** (NES Dictionary) - to predict costs.
Generation of detailed and realistic forecasts of hours, material costs,
or other requirements for a task, subtask, operation, or a part or
groups thereof - generally in response to a request for proposal or
specific statement of work. The art of approximating the probable worth
(or cost), extent, quantity, quality, or character of something based on
information available at the time. It also covers the generation of
forecasted costing rates and factors with which estimate numbers may be
converted to costs, and the application of these costing rates and
factors to \"estimate numbers\" to establish forecasted costs.

**[Expert Judgment Models]{.underline}** - use a method of software
estimation that is based on consultation with one or more experts that
have experience with similar projects. An expert-consensus mechanism
such as the *DELPHI TECHNIQUE* may be used to produce the estimate.

**[Fixed Year Dollars]{.underline}** - dollars that have been adjusted
for inflation to a specific year.

**[Historical Data]{.underline}** - a term used to describe a set of
data reflecting actual cost or past experience of a product or process.

**[Improvement Curve]{.underline}** - a graphical representation of
improvement curve theory that projects resource requirements versus the
number of units produced. Examples include labor hours, labor cost,
direct cost including labor and materials. When reflecting only labor
hours the curve is usually called a learning curve. When depicting cost,
it is normally referred to as a Cost Improvement Curve.

**[Inflation]{.underline}** - an increase in the level of prices for the
same item(s). Examples of indices that reflect inflation include
Consumer Price Index (CPI), Wholesale Price Index, and Producer Price
Index. When prices decline it is called deflation.

**[Knowledge Base]{.underline}** - the repository of knowledge in a
computer system or organization. The collection of data, rules, and
processes that are used to control a system, especially one using
artificial intelligence or expert system methods.

**[Life Cycle]{.underline}** - the stages and process through which
hardware or software passes during its development and operational use.
The useful life of a system. Its length depends on the nature and
volatility of the business, as well as the software development tools
used to generate the databases and applications.

**[Management Information Systems]{.underline}** - a computer based
system of processing and organizing information that provides different
levels of management within an organization with accurate and timely
information needed for supervising activities, tracking progress, making
decisions, and isolating and solving problems.

**[Metric]{.underline}** - Quantitative analysis values calculated
according to a precise definition and used to establish comparative
aspects of development progress, quality assessment or choice of
options.

**[Normalize]{.underline}** - to adjust data (normally cost data) for
effects like inflation, anomalies, seasonal patterns, technology
changes, accounting system changes, reorganizations, etc.

**[Operation]{.underline}** (Philip Morse: Notes on Operations Research,
MIT Press 1962) - an operation is a pattern of activity of men or of men
and machines, engaged in carrying out a cooperative and usually
repetitive task, with pre-set goals and according to specified rules of
operation.

**[Operational Research]{.underline}** (Operational Research Quarterly,
Vol. 13, No. 3, 282 (Sept. 1962)) - operational research is the attack
of modern science on complex problems arising in the direction and
management of large systems of men, machines, materials, and money in
industry, business, government, and defense. The distinctive approach is
to develop a scientific model of the system, incorporating measurements
of factors such as chance and risk, with which to predict and compare
the outcomes of alternative decisions, strategies, or controls. The
purpose is to help management determine its policies and actions
scientifically.

**[Operations Research]{.underline}** (Norse, same as above) - the
scientific study of operations.

**[Organic Mode]{.underline}** - a term used by COCOMO to describe a
project that is developed in a familiar, stable environment. The product
is similar to previously developed products. Most people connected with
the project have extensive experience in working with related systems
and have a thorough understanding of the project. The project contains a
minimum of innovative data processing architectures or algorithms. The
product requires little innovation and is relatively small, rarely
greater than 50,000 DSIs.

**[Paradigm]{.underline}** - a model, example, or pattern. A generally
accepted way of thinking.

**[Parametric Cost Estimate]{.underline}** - Estimate derived from
statistical correlation of historic system costs with performance and/or
physical attributes of the system.

**[Parametric Cost Estimating Methods]{.underline}** - Estimating
methods based on physical or performance characteristics and schedules
of the end items.

**[Parametric Cost Model]{.underline}** - A mathematical representation
of parametric cost estimating relationships that provides a logical and
predictable correlation between the physical or functional
characteristics of a system, and the resultant cost of the system. A
parametric cost model is an estimating system comprising cost estimating
relationships (CERs) and other parametric estimating functions, e.g.,
cost quantity relationships, inflation factors, staff skills, schedules,
etc. Parametric cost models yield product or service costs at designated
levels and may provide departmentalized breakdown of generic cost
elements. A parametric cost model provides a logical and repeatable
relationship between input variables and resultant costs.

**[Parametric Estimating]{.underline}** - a mathematical procedure where
product or service descriptors (parameters) and cost algorithms directly
yield consistent cost information.

**[Platform]{.underline}** - hardware or software architecture of a
particular model or family of computers. The term sometimes refers to
the hardware and its operating system.

**[Procedures]{.underline}** - manual procedures are human tasks.
Machine procedures are lists of routines or programs to be executed,
such as described by the Job Control Language (JCL) in a mini or
mainframe, or the batch processing language in a personal computer.

**[Process]{.underline}** - the sequence of activities (in software
development) described in terms of the user roles, user tasks, rules,
events, work products, resource use, and the relationships between them.
It may include the specific design methodology, language, documentation
standards, etc.

**[Production Rate]{.underline}** - the number of items produced in a
given time period (e.g., items/month).

**[Program Evaluation]{.underline}** (DoDI 7041.3) - is the economic
analysis of on-going actions to determine how best to improve an
approved program/project based on actual performance. Program evaluation
studies entail a comparison of actual performance with the approved
program/project.

**[Program Evaluation and Review Technique: PERT]{.underline}** - a
method used to size a software or hardware product and calculate the
Standard Deviation (SD) for risk assessment. For example, the PERT
equation (beta distribution) estimates the Equivalent Delivered Source
Instructions (EDBIs) and the SD based on the analyst\'s estimates of the
lowest possible size, the most likely size, and the highest possible
size of each Computer Program Component (CPC).

**[Program Work Breakdown Structure]{.underline}** - A program work
breakdown structure covers the entire acquisition cycle of a program,
consists of at least the first three levels of a work breakdown
structure, as prescribed by MIL-STD-881B, and its extension by the DoD
Component and/or contractor(s). The program work breakdown structure has
uniform element terminology, definition, and placement in the
family-tree structure.

**[Rapid Prototyping]{.underline}** - the creation of a working model of
a software module to demonstrate the feasibility of the function. The
prototype is later refined for inclusion in a final product.

**[Rayleigh Distribution]{.underline}** - a curve that yields a good
approximation to the actual labor curves on software projects.

**[Real-Time]{.underline}** - (1) Immediate response. The term may refer
to fast transaction processing systems in business; however, it is
normally used to refer to process control applications. For example, in
avionics and space flight, real-time computers must respond instantly to
signals sent to them.

\(2\) Any electronic operation that is performed in the same time frame
as its real-world counterpart. For example, it takes a fast computer to
simulate complex, solid models moving on screen at the same rate they
move in the real world. Real-time video transmission produces a live
broadcast.

**[Re-engineering]{.underline}** - process of restructuring and
redesigning an operational (or coded) hardware or software system or
process in order to make it meet certain style, structure, or
performance standards.

**[Resource Analysis]{.underline}** (Fisher) - systematically
determining the economic resource impact of alternative proposals for
future courses of action.

**[Resources]{.underline}** (Fisher) - raw materials, skilled personnel,
scarce materials or chemicals, etc.

**[Resources]{.underline}** (NES Dictionary) - consists of facilities,
equipment, management, personnel, laboratories, and scientific,
technical, and manufacturing capability.

**[Reusability]{.underline}** - ability to use all or the greater part
of the same programming code or system design in another application.

**[Reuse]{.underline}** - software development technique that allows the
design and construction of reusable modules, objects, or units, that are
stored in a library or database for future use in new applications.
Reuse can be applied to any methodology in the construction phase, but
is most effective when object oriented design methodologies are used.

**[Schedule]{.underline}** - a time display of the milestone events and
activities of a program or project.

**[Scope]{.underline}** - a definition of how, when, where, and what a
project is expected to include and accomplish.

**[Security]{.underline}** - the protection from accidental or malicious
access, use, modification, destruction, or disclosure. There are two
aspects to security, confidentiality and integrity.

**[Semi-detached Mode]{.underline}** - a term used by COCOMO to describe
a project that is developed somewhere between organic and embedded. The
team members have a mixture of experienced and inexperienced personnel.
The software to be developed has some characteristics of both organic
and embedded modes. Semi-detached software can be as large as 300K DSIs.

**[Should Cost Estimate]{.underline}** - An estimate of contract price
which reflects reasonably achievable economy and efficiency. It is
generally accomplished by a team of procurement, contract
administration, cost analysis, audit and engineering representatives
performing an in-depth analysis of cost and cost effects. Its purpose is
to develop realistic cost objectives.

**[Software Development Life Cycle]{.underline}** - the stages and
process through which software passes during its development. This
includes requirements definition, analysis, design, coding, testing, and
maintenance.

**[Software Development Life Cycle Methodology]{.underline}** -
application of methods, rules, and postulates to the software
development process to establish completeness criteria, assure an
efficient process, and develop a high quality product.

**[Software Method]{.underline}** - (or Software Methodology) - focuses
on how to navigate through each phase of the software process model
(determining data, control, or uses hierarchies; partitioning functions;
and allocating requirements) and how to represent phase products
(structure charts; stimulus-response threads; and state transition
diagrams).

**[Software Tool]{.underline}** - program that aids in the development
of other software programs. It may assist the programmer in the design,
code, compile, link, edit, or debug phases.

**[Systems Analysis]{.underline}** (Fisher) - Systems analysis may be
defined as inquiry to assist decisionmakers in choosing preferred future
courses of action by (1) systematically examining and reexamining the
relevant objectives and the alternative policies or strategies for
achieving them; and (2) comparing quantitatively where possible the
economic costs, effectiveness {benefits), and risks of alternatives.

**[Technical Non-Cost Data]{.underline}** - engineering variables that
describe the item, subsystem or system. The source of this data includes
engineering documents, engineering drawings and works of a technical
nature which are specified to be delivered pursuant to the contract.

**[Top-Down Models]{.underline}** - use a method of estimation that
estimates the overall cost and effort of the proposed project derived
from global properties of the project. The total cost and schedule is
partitioned into components for planning purposes.

**[Update]{.underline}** - to update an estimate or CER means to utilize
the most recent data to make it current, accurate and complete.

**[Validation]{.underline}** - in terms of a cost model, a process used
to determine whether the model selected for a particular estimate is a
reliable predictor of costs for the type of system being estimated.

**[Work Breakdown Structure]{.underline}** - A work breakdown structure
is a product-oriented family tree, composed of hardware, software,
services, data and facilities which results from system engineering
efforts during the development and production of a defense material
item, and which completely defines the program. A work breakdown
structure displays and defines the product(s) to be developed or
produced and relates the elements of work to be accomplished to each
other and to the end product. MIL-STD 881B is the modern standard for
developing a WBS. (See Appendix B for more information.)

**[Workstation]{.underline}** - high-performance, single user
microcomputer or minicomputer that has been specialized for graphics,
CAD, CAE, or scientific application.