Weighting of Functional Components

Once the functional components have been identified and classified they are evaluated for their functional complexity using a set of prescribed attributes. The functions are categorised into low, average or high complexity.

Functional components are awarded Function Points according to their classification of type and categorisation of complexity.

E.g.:

Create Fault record

= External Input = High Complexity = 6 Function Points

Currency Conversion File

= Internal Logical File = Low Complexity = 7 Function Points

Once all functional components are identified, classified into type, assessed for complexity and awarded ‘points’ these points are accumulated into a total Function Point Count. NOTE: IFPUG 4.3 records this size as the Functional Size. Any further adjustment is not recommended.

Previous versions of the IFPUG Methodology had a final step is to adjust this count for quality and technical characteristics by using the value adjustment factor (range 0.65 – 1.35) for the Adjusted Function Point Count. This step is now an optional add-on for IFPUG and not recommended.