A replicated study on correlating agile team velocity measured in function and story points

Since the rapid growth of agile development methods for software engineering, more and more organizations measure the size of iterations, releases, and projects in both function points and story points. In 2011 Santana et al. performed a case study on the relation between function points and story points, from data collected in a Brazilian Government Agency. In this paper we replicate this study, using data collected in a Dutch banking organization. Based on a statistical correlation test we find that a comparison between function points and story points as measured in our repository indicates a moderate negative linear relation, where Santana et al. concluded a strong positive linear relation between both size metrics in their case study. Based on the outcome of our study we conclude that it appears too early to make generic claims on the relation between function points and story points; in fact FSM-theory seems to underpin that such a relationship is a spurious one.