[3] Function points were defined in 1979 in Measuring Application Development Productivity by Allan J. Albrecht at IBM.
[4] The functional user requirements of the software are identified and each one is categorized into one of five types: outputs, inquiries, inputs, internal files, and external interfaces.
Recently there have been different approaches proposed to deal with this perceived weakness, implemented in several commercial software products.
In addition, there have been multiple attempts to address perceived shortcomings with the measure by augmenting the counting regimen.
[10][11][12][13][14][15] Others have offered solutions to circumvent the challenges by developing alternative methods which create a proxy for the amount of functionality delivered.