Adjust for What You Don t Know


Adjust for What You Don't Know

You are counting function points during the requirements activity. You may not have all the data you need for a completely accurate function point count. In the preceding sections, we showed how you count function points using inputs, outputs, inquiries, internal files, and external files. However, even if you do not have all five of these parameters, you can still count function points. The count is simply adjusted according to how many of these parameters are available.

Table C.6 gives the range of uncertainty depending on the number of parameters used in your count. For example, if you used only three parameterssay, the inputs, outputs, and inquiries (these are the easiest to use because they are the data flows on the context model)then your function point count would be accurate within a range of ±15%.

Table C.6. Uncertainty Ranges Based on the Number of Parameters Used in Function Point Counting

Number of Parameters Used

Range of Uncertainty

1

±40%

2

±20%

3

±15%

4

±10%

5

±5%

Source: Capers Jones





Mastering the Requirements Process
Mastering the Requirements Process (2nd Edition)
ISBN: 0321419499
EAN: 2147483647
Year: 2006
Pages: 371

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