Software Non-functional Assessment Process (SNAP) Assessment Practices Manual, Release 2.4

Having both functional size and non-functional size provides a complete picture of software product development. The functional size is quantifiable and represents a good measure of the functional project/application size. Providing a quantifiable measure for the Non-Functional Requirements (NFR) allows organizations to build historical data repositories that can be referenced to assist in decision making for the technical and/or quality aspects of applications.

A non-functional assessment will assist Information Technology (IT) organizations in multiple ways. It will provide insight into projects and applications to assist in estimating and in the analysis of quality and productivity. Used in conjunction with function point analysis, the non-functional assessment provides information that can identify items impacting quality and productivity in a positive or negative way. Having this information enables software professionals to:

  • better plan, schedule and estimate projects,
  • identify areas of process improvement,
  • assist in determining future technical strategies,
  • quantify the impacts of the current technical strategies, and
  • provide specific data when communicating non-functional issues to various audiences.

The primary objectives of the IFPUG Assessment Practices Manual are to:

  • provide a clear and detailed description of Non-functional Assessment;
  • ensure that assessments are consistent;
  • provide guidance to allow a non-functional assessment to be applied to popular methodologies and techniques; and
  • provide a common understanding to allow tool vendors to provide automated support for non-functional assessment.

The standard in this manual should be applied by anyone to assess non-functional product size. The manual was designed for use by persons new to assessment as well as those who were trained and users with intermediate and advanced experience.


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