• Decisions documented to different levels of detail
• Results within different bounds of accuracy.

The metrics consulting company, Total Metrics, has documented this concept and developed a way of describing the different levels of function point counting. Total Metrics has allowed the ISBSG to use the contents of a paper on this subject that Pam Morris presented at the IFPUG and ACOSM conferences. A PDF version of the complete paper can be downloaded. The paper details the contents, attributes, issues and pre-requisites for each of the levels. Other organisations have adopted their own counting level definitions. The ISBSG welcomes comments on this paper with a view to eventually establishing an accepted industry approach to counting levels.

Abstract

The level of detail for a particular count will depend on the purpose for which the count will be used. Different purposes will require different degrees of accuracy and detail in the documentation and consequently different counting rates. The optimal level of counting may not always be able to be achieved in a particular situation, since the level actually selected may be constrained by:

• the quality of project or application documentation available,
• the time in which the count must be completed,

The paper describes a number of levels of function point counting that could be used to suit different uses. The suggestion is that you should choose a particular counting level based on how the results will be used and your assessment of the quality of the information available to provide background on the count.
A particular function point count may be conducted at one of the following levels of detail:

• Detailed Linked and Labeled Count
• Detailed Linked Count
• Detailed Count
• Default Complexity Count
• Rough Count
• Size Approximation.

The paper that details the contents, attributes, issues and pre-requisites for each of the levels listed can be downloaded here.