The COSMIC Functional Size Measurement Method – Advanced and Related Topics

Abran, A., Londeix, B., O’Neill M., Santillo L.,Vogelezang F.,

This ‘Advanced and Related Topics’ document has two purposes.
First, the document contains material on the COSMIC method v3.0 that is intended for advanced
practitioners, i.e. measurement specialists who have already mastered the concepts of the method as
described in the ‘Measurement Manual’ (see below). This first edition of this document mainly
addresses the topic of ensuring comparability of measurements made on functional user requirements
(‘FUR’) early in the life of a large software project, when the requirements may typically be in the
process of being sub-divided and worked out in more detail by different teams of requirements
engineers working in parallel. When such partially-developed statements of FUR are encountered, the
measurer must be aware of the verification checks that should be made to ensure that measurements
made on different parts of the FUR are comparable. The same verification checks may be needed
when measurements of FUR are received from different sources.
Second, the document contains material that is not part of the basic COSMIC method, but which is
highly relevant to its practical use. In this first edition of this document, two related topics are covered,
namely ‘early or rapid approximate sizing using the COSMIC method’ and ‘convertibility’ (i.e. methods
of converting sizes measured using the COSMIC method to or from sizes measured using ‘1st
generation’ functional size measurement (FSM) Methods). A basic mastery of the concepts of the
Measurement Manual is also necessary to understand both these topics.


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