uTips (Usage Tips) provide insight into potential uses of function points to support an organization’s business needs. While uTips provide insight on usage opportunities, they do not provide detailed direction on the application of the IFPUG FPA method in a particularsituation. When necessary, the uTip may be followed by additional content on the topic providing specific how-to guidance. uTips are not rules, but rather interpretation and application of the rules, and provide guidance using a realistic example to explain the topic being covered.

This uTip is focused on describing the IFPUG FPA method as it applies to sizing and cost estimating in the early stages of the software development lifecycle, as well as sizing in a fast way. This document presents three methods for approximating FPA: High Level FPA, Indicative FPA and Simple Function points. This uTip is not an exhaustive examination of the subject. At the end of the document, suggestions for further reading are provided.

Myths

·     “You cannot apply FPA in early stages of the software development process, so in the practice of budgeting software development FPA is useless.”

·     “You need a high level of detail of the functional user requirements before you can successfully apply FPA.”

·     “Cost estimating and budgeting using FPA takes lots of time. It’s not worth the effort”.

No! No! No! These three widespread misunderstandings prevent people from benefiting from FPA at virtually any moment!

The CPM [1] states that FPA estimates are possible by making assumptions about unknown functions and/or their complexity in order to determine an approximate functional size (part 2, page 3-8).

Moreover, in 2019 IFPUG acquired a lightweight functional measurement method, compliant with the ISO14143-1 standard, to increase the acceptance of functional sizing in all communities of software developers: the Simple Function Point method. An IFPUG Task Force, including members of the FSSC and NFSSC, spent two years analyzing and experimenting with the method, and completed its task producing Version 2.1 of the Simple Function Points Manual in October 2021[5].

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