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Function Point Analysis: Introduction and Basic Overview as an Alternative to SLOC-based Estimation

Software & IT Track

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When analyzing and estimating the costs for a software application, most cost estimators inherently rely on problematic, “SLOC-centric” estimation techniques. Cost analysts typically strive for concrete, tangible numbers to work with in order to produce relationships and parametric trends in historical and future cost data.

However, the use of SLOC-based techniques often poses several problems. When an estimator relies on code counts and programming languages, the initial estimate is rarely on-par with the actual code count, usually due to creep, different code writing abilities, and/or lack of fluidity in individual code packages. Programmers also tend to adhere to the “programmer-use” view when designing an application rather than the end user. Different programmers write code in different styles, and different languages require different lengths of code for similar processing logic. Furthermore, many programs are written in multiple languages, making it difficult to estimate an accurate SLOC count.

A solution to these innate and, in most cases, eminent problems with SLOC estimation is the employment of Function Point Analysis. Function Point Analysis quantifies the actual functionality within a software application as identified by the end-user. Simply speaking, function points are the user – identified aspects of an application that are integral in that application’s execution. The function point estimation technique is independent of programming language and is unchanged by expanded or decreased lines of code. This presentation introduces the inherent problems associated with SLOC estimation, introduces the Function Point Analysis solution, reviews the benefits and criticisms, and provides recommendations for future usage. It also utilizes a simple customer billing system example to explain the methodology associated with function point analysis.


Tucker Moore
TASC, Inc.
Tucker S. Moore is an Operations Research Analyst for the Analytical Solutions Unit at TASC Inc.
(formerly Northrop Grumman Corp). He is currently responsible for creating and analyzing life cycle cost estimates and logistics funding summaries for various programs within the Department of Defense at United States Marine Corp Base Quantico. Mr. Moore is also experienced with facilities cost estimates for commercial and federal projects, has participated in internal independent cost estimates for several TASC / Northrop Grumman contracts, and is a trained function point counter. He has supported various agencies within the Department of Defense (DoD), the Federal Aviation Administration (FAA), and the New York City government. Mr. Moore is a graduate of the University of Virginia School of Engineering and Applied Sciences, holding a Bachelors Degree in Mechanical Engineering as well as a Minor in Aerospace Engineering.