An Overview of Function Point Analysis - Rating and Ranking the Components
(Page 3 of 4 )

Once all the components in the application have been classified as one of the five major components mentioned above, they have to be rated as either Low, Average, or High.

Ranking is commonly based on File Types Referenced, Data Element Types and Record Element Types.

File Types Referenced (FTRs) represents the total number of internal logical files (ILFs) maintained, read, or referenced, and the external interface files read or referenced by the EI/EO transaction.

Data Element Type (DET) can be defined as unique user-recognizable non-recursive fields including foreign key attributes that are maintained on ILF/EIF.

Record Element Type (RET) is a subgroup of data elements within an ILF/EIF.

For each of the components belonging to Transactional functions, the ranking is based on:

1. Number of files updated or referenced (FTRs) and
2. Number of data element types (DETs)

For the data components viz., Internal Logical Files (ILF) and External Interface Files (EIF), ranking is based on:

1. Number of Data Element Types (DETs) and
2. Number of Record Element Types (RETs)

The tables given below provide an example of rankings and ratings given to each component.

External Inputs

FTRs	Data Elements
	1-4	5-15	>15
0-1	Low	Low	Average
2	Low	Average	High
>=3	Average	High	High

External Output/External Inquiries

FTRs	Data Elements
	1-5	6-19	>19
0-1	Low	Low	Average
2-3	Low	Average	High
>3	Average	High	High

Values or Ratings for Transactions

Ranking	Data Elements
	External Input	External Output	External Inquiry
Low	3	4	3
Average	4	5	4
High	6	7	6

In the above example, if an external input component updates 2 FTRs and references around 16 data elements then the ranking would be HIGH and the associated rating would be 6.

Rankings for ILFs and EIFs

Record Elements	Data Elements
	1-19	20-50	>50
1	Low	Low	Average
2-5	Low	Average	High
>5	Average	High	High

Values or Ratings

Ranking	Data Elements
	Internal Logical File	External Interface File
Low	7	5
Average	10	7
High	15	10

Next: Unadjusted Function Points >>
 

More Practices Articles
More By Nandini Venugopalan

Comments On: An Overview of Function Point Analysis

>>> Be the FIRST to comment on this article!