Functional size measurement methods

"Functional Size Measurement (FSM) is a technique used to measure the size of software by quantifying the Functional User Requirements of the software" [1].

"Functional Size Measurement Method (FSMM) is a specific implementation of FSM defined by a set of rules, which conforms to the mandatory features of ISO/IEC 14143-1:2007" [1]
In 1979, Allan Albrecht published the first functional size measurement method known as Function Point Analysis. Afterwards, several extensions and variations of this method have been produced. The current functional size measurement (FSM) methods are [2-4]:

  •     ISO 20926:2009 IFPUG 4.1 functional size measurement method
  •     ISO 19761:2011 COSMIC functional size measurement method
  •     ISO 24570:2005 NESMA functional size measurement method
  •     ISO 20968:2002 MKII function point analysis
  •     ISO 29881:2010 FiSMA 1.1 functional size measurement method

The first two ISO FSM methods are the most commonly used [5, 6].