Why we should use function points [software metrics]

Function point analysis helps developers and users quantify the size and complexity of software application functions in a way that is useful to software users. Are function points a perfect metric? No. Are they a useful metric? In the author's experience, yes. Function points are technologically independent, consistent, repeatable, and help normalize data, enable comparisons, and set project scope and client expectations. The author addresses these issues from the perspective of a practitioner who uses the International Function Point Users Group's Counting Practices Manual, Release 4.0 rules for counting function points. Of course, other function point standards exist, including Mark II and Albrecht's original rules.