Function Point Analysis (FPA) is a sizing measure of clear business significance. First made public by Allan Albrecht of IBM in 1979, the FPA technique quantifies the functions contained within software in terms that are meaningful to the software users. The measure relates directly to the business requirements that the software is intended to address. It can therefore be readily applied across a wide range of development environments and throughout the life of a development project, from early requirements definition to full operational use. Other business measures, such as the productivity of the development process and the cost per unit to support the software, can also be readily derived.The function point measure itself is derived in a number of stages. Using a standardized set of basic criteria, each of the business functions is a numeric index according to its type and complexity. These indices are totaled to give an initial measure of size which is then normalized by incorporating a number of factors relating to the software as a whole. The end result is a single number called the Function Point index which measures the size and complexity of the software product.
In summary, the function point technique provides an objective, comparative measure that assists in the evaluation, planning, management and control of software production.