Function Point Modeler creates three types of function point counts, which are specified by IFPUG.
The fallowing dialog shows all three types of function point counts in the Function Point Modeler Project Explorer.
The fallowing picture shows the relation between the software life cycle and all three types of function point counts.
The development project function point is used for the new development projects. The development project function point calculation consists of three components of functionality:
Function Point Formula
Use the following formula to calculate the development project function point count.
DFP = (UFP + CFP) * VAF
Where:
DFP is the development project function point count
UFP is the unadjusted function point count for the functions that will be available after installation
CFP is the unadjusted function points added by the conversion unadjusted function point count
VAF is the value adjustment factor
Note: After software installation, the application function point count is calculated using components of the development project function point count.
The enhancement project function point calculation consists of three components of functionality:
Application Functionality
Application functionality consists of:
• Function points identified from the functionality that is added by the enhancements
• Function points counted because existing functionality is changed during the enhancement project
• Function points counted for functionality deleted during the enhancement projectFunction Point Formula
Use the following formula to calculate the enhancement project function point count.
Note: Data conversion requirements are included in this count.
EFP = [(ADD + CHGA + CFP) * VAFA] + (DEL* VAFB)
Where:
EFP is the enhancement project function point count.
ADD is the unadjusted function point count of those functions that were or will be added by the enhancement project.
CHGA is the unadjusted function point count of those functions that were or will be modified by the enhancement project. This number reflects the size of the functions after the modifications.
CFP is the function point count of those functions added by the conversion
VAFA is the value adjustment factor of the application after the enhancement project is complete.
DEL is the unadjusted function point count of those functions that were or will be deleted by the enhancement project.
VAFB is the value adjustment factor of the application before the enhancement project begins.
Note: When an enhancement project is installed, the application function point count must be updated to reflect changes in the application's functionality.
This section provides the formulas to calculate the application function point count. There are two variations of this formula:
Formula to Establish the Initial Count
Use the formula in this section to establish the initial function point count for an application. Initially, the user is receiving new functionality. There are no changes to the existing functionality or deletions of obsolete or unneeded functionality. The application function point count does not include conversion requirements.
AFP = ADD * VAF
Where:
AFP is the initial application function point count.
ADD is the unadjusted function point count of those functions that were installed by the development project.
VAF is the value adjustment factor of the application.Formula to Reflect Enhancement Projects
When an enhancement project is installed, the existing application function point count must be updated to reflect modifications to the application. The functionality for the application can be altered in one or more ways:
• Added (new) functionality increases the size of the application
• Changed functionality increases, decreases, or has no effect on the size of the application
• Deleted functionality decreases the application size
• Changes to the value adjustment factor increase or decrease the application size
Note: Because conversion functionality does not affect the application function point count, any conversion functionality associated with an enhancement project is omitted entirely from the application function point calculation.
Use the following formula to calculate the application function point count after an enhancement project:AFP = [(UFPB + ADD + CHGA) - (CHGB + DEL)] * VAFA
Where:
AFP is the application's adjusted function point count.
UFPB is the application's unadjusted function point count before the enhancement project begins.
Note: If this count is unavailable, it can be calculated using the formula UFBP = AFPB/VAFB; where AFPB is the adjusted application function point count before the enhancement project. VAFB is the value adjustment factor of the application before the enhancement project.
ADD is the unadjusted function point count of those functions that were added by the enhancement project.
CHGA is the unadjusted function point count of those functions that were changed by the enhancement project. This number reflects the size of the functions after the changes.
CHGB is the unadjusted function point count of those functions that were changed by the enhancement project. This number reflects the size of the functions before the changes were made.
DEL is the unadjusted function point count of those functions that were deleted by the enhancement project.
VAFA is the value adjustment factor of the application after the enhancement project is complete.
Refer to IFPUG document Function Point Counting Practices Manual for additional information about the function point analysis, or see the IFPUG web site at http://www.ifpug.org for additional information.
Create a copy from
Create an application count from
Create an enhancement project count from
Create a new count from an existing count
