Complexity Weights

The complexity weights for the different functions are given as follows:

		LOW	AVERAGE	HIGH
Internal Logical File	ILF	7	10	15
External Interface File	EIF	5	7	10
External Input	EI	3	4	6
External Output	EO	4	5	7
External Inquiry	EQ	3	4	6

Value Adjustment Factor and Adjusted Function Points

The unadjusted function point count is adjusted by multiplying it by the Value Adjustment Factor (VAF) to produce the final adjusted function point count. The Value Adjustment Factor is determined from the ratings of 14 “General System Characteristics” (GSC) that are intended to take into account special requirements placed on the application.

The 14 General System Characteristics are as follows:

Trait	Description
Data Communications	The degree to which communication facilities are required for the application
Distributed Functions	The existence of distributed functions in the application
Performance	The degree to which performance is a critical issue
Heavily Used Configuration	The installation of the application on current equipment that is heavily used
Transaction Rate	The measurement of the transaction rate
On-line Data Entry	The complexity of on-line data transactions with consideration to the number of screens and functions
End User Efficiency	The degree to which on-line functions promote end user efficiency
On-line Update	The use of on-line updates to master files
Complex Processing	The amount of complex processing. Complex processing may have many control interactions and decision points, a significant number of logical and mathematical equations, or extensive exception processing
Reusability	The evaluation of code in terms of reusability
Installation Ease	The degree to which the application is easily installed
Operational Ease	The proficiency of the application's general operations such as startup, backup, recovery, and shutdown
Multiple Sites	The number of installations of the application across diverse organizations or sites
Facilitate Change	The appraisal of the application in terms of how easily it accommodates user modifications such as providing a flexible query facility or functions for setting and maintaining user-defined parameters

Each of these are rated numerically from 0 (not present or no influence) to 5 (strong influence throughout). The scores of all 14 GSCs are summed to produce a “Total Degree of Influence” (TDI). The Value Adjustment Factor is obtained by dividing the Total Degree of Influence by 100 and adding the result to 0.65. Thus the VAF will have a value from 0.65 to 1.35.

The adjusted function point count is the product of the unadjusted count and the value adjustment factor. The adjusted function point count can be used to produce an estimate of source lines of code by using the Backfire Method.