Demystifying Function Points

Clarifying Common Terminology

This list of commonly misunderstood words is not exhaustive, and other words and acronyms can form barriers to understanding of function points.

Table 1 summarizes the terms covered in this article:


Meaning in IT

Meaning in Function Point Counting


Typically includes both conceptual and design considerations. Even logical data models often contain physical components.

Refers to logical functions and logical user requirements. Conceptual, from a user business perspective. Does not include design or quality considerations. Reflects what the software must do, not how.


Physical person who uses or specifies requirements for the software.

Person, thing, other application, department, etc. that provides functional user requirements for the software.

Application (system)

Physical implementation of software. The boundary of an application or system often coincides with physical hardware or software boundaries.

A cohesive collection of automated procedures and data supporting a business objective.


Depending on the organization, can include new development, changes, or enhancements to multiple applications.

Pertains to the work product done on a single application:

·         Development: The specification, construction, testing, and delivery of a new information system.

·         Enhancement: The modification of an existing application.

Enhancement (enhancement project)

Any modification to the software including functional, non-functional, technical, cosmetic, data administration, or design changes that increase the business value of the software.

Functional modifications to the elementary processes of the application (e.g., new/ modified/removed functions: EI, EO, EQ, ILF or EIF).


Dataset, or physical assemblage of data, as in output file, input file, data file, research file, etc.

A logically related group of data, not the physical implementation of those groups of data.

Functional size measurement and function points are not rocket science; they simply provide an objective, repeatable process for assessing the logical size of software based on functional user requirements. By understanding some of the terminology that can trip up developers and novice counters, this article will, hopefully, demystify the perceived complexities involved in function point counting.

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