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theorycomputation-theoryfunction-points

How to calculate function points

This is a question about theoretical computing. I have came through a question like below;

Consider a project with the following functional units :

  • Number of user inputs = 50
  • Number of user outputs = 40
  • Number of user enquiries = 35
  • Number of user files = 06
  • Number of external interfaces = 04

Assuming all complexity adjustment factors and weighing factors as average, the function points for the project will be;

The answer is 672. How is this calculated?

Solution

  • 1. Typical complexity averages are as follows:

    Table of function-points average

    AVERAGE complexity weights = {4, 5, 4, 10, 7} for the 5 complexities respectively.

    2. Typical Characteristic weights are as follows:

    Table of characteristics weights

    AVERAGE characteristic weight = 3.

    3. Function point = FP = UFP x VAF

    UFP = Sum of all the complexities i.e. the 5 parameters provided in the question,
    VAF = Value added Factor i.e. 0.65 + (0.01 * TDI),
    TDI = Total Degree of Influence of the 14 General System Characteristics.

    functional-points calculation

    Thus function points can be calculated as:

    = (200 + 200 + 140 + 60 + 28) x (0.65 + (0.01 x (14 x 3))
= 628 x (0.65 + 0.42)
= 628 x (1.07)
= 672

    Thus the function points for the project will be 672.

    Checkout this article for a detailed walk-through into function-point calculations.