Metrics Function Points
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A function point is a unit of measurement to express the amount of business functionality an information system provides to a user. The cost (in dollars or hours) of a single unit is calculated from past projects [1]. As of 2012, there are five recognized ISO standards for functionally sizing software:
- COSMIC-FFP [2]: ISO/IEC 19761:2003 Software engineering. A functional size measurement method.
- FiSMA FSM: ISO/IEC 29881:2008 Information technology - Software and systems engineering - FiSMA 1.1 functional size measurement method.
- IFPUG FSM Method [3]: ISO/IEC 20926:2009 Software and systems engineering - Software measurement - IFPUG functional size measurement method
- Mk II Function Point Analysis: ISO/IEC 20968:2002 Software engineering - Ml II Function Point Analysis - Counting Practices Manual
- NESMA FPA Method [4]: ISO/IEC 24570:2005 Software engineering - NESMA function size measurement method version 2.1 - Definitions and counting guidelines for the application of Function Point Analysis
BackFiring FPA
Function point analysis is a well known established method to estimate the size of software systems and software projects. Originally the method was used in the early phases of the waterfall model such that the implementation effort was estimated on the basis of the I/O-behavior as defined in the functional documentation. Later, one was able to obtain a first order estimation of the size of a software system, based on the number of lines of code of the system (LOC). This method is known as backfiring [5].
Recent research has shown that just by different programming styles of individual programmers to large fluctuations in this factor.
Not to mention the type of application.
If we all would make use of backfiring, then only for large applications (so that the "law of large numbers" may apply),
and even then the results should be handled with great caution.
In this subject also the term 'gearing factor'is mentioned, from FP to LoC, which is the opposite of backfire function points , from LoC to FP.
See also
References
- ↑ Wikipedia Function point, definitions and links.
- ↑ COSMIC, COmmon Software Measurement International Consortium ffp Cosmic ISO 19761]
- ↑ IFPUG, The International Function Point Users Group.
- ↑ NESMA, the NEderlanths Software Metrics users Association.
- ↑ Source-Code-FPA, Source Code Based Function Point Analysis for Enhancement Projects, Steven Klusener, Software Improvement Group, Kruislaan 419, NL-1098 SJ Amsterdam, Vrije Universiteit, De Boelelaan 1081a, NL-1081 HV Amsterdam, Email: steven@software-improvers.com
