Function Points

Function Points are units of measure for functional size as defined within the IFPUG Functional Size Measurement (FSM) Method and it is the major global functional sizing methodology.

FP is a standard method for quantifying the software deliverable based upon the user view, where:

  • User is any person or thing that communicates or interacts with the software at any time
  • User View is the Functional User Requirements as seen by the user
  • Functional user requirements describe what the software shall do, in terms of tasks and services.

It is also important to keep in mind that function points look at the logical view, not the physical. So things like coding algorithms, database structure, screenshots of transactions are not counted.

Things that are counted within the Function Points methodology:

  • Input files and input transactions (batch interfaces)
  • Screens (adds, changes, deletes)
  • Control Information
  • Internal Logical Files (tables, files with data, control files)
  • External tables and referenced files from other applications
  • Output files and transactions (batch interfaces)
  • Other outputs - reports, files, dvd's, views, notices, warnings

For the real-life use of FP and examples please refer to the Function Points in practice section on our pages.

The FunctionPoints portal

The portal provides articles, case studies and knowledge base on project esimation and functional size measurement methodologies based on Function Point Analysis.

We are constantly updating our resources base. If you have any software suggestions or would like to submit an article, please contact us.