Evaluation of Convertibility Issues between IFPUG and COSMIC Function Points

Software industry has matured with time, from small application of few lines of codes to software application of millions of lines of code. In the past few years, the concern of the industry regarding software size estimation has been the convertibility issue between the International Function Point User Group (IFPUG) and the COmmon Software Measurement International Consortium (COSMIC) in order to leverage their huge investment on the IFPUG. Since there is still no cost and effort estimation tool for COSMIC function points. IFPUG is one of the early estimation methods, however, with the introduction of a more scientific method like COSMIC which has a wider applicability than the IFPUG and both method using the same measuring unit and principle, the continued relevancy of the IFPUG is called to question. Due to similar underlining principle of the two methods and for organizations that have invested so much in the IFPUG not to lose all their investment because of migrating to using COSMIC, researchers have been trying to explore the possibility of converting the output of one method to the other. This paper review some of the popular conversion formulas that have been suggested so far to see a trend or how related, consistent and reliable the formulas could be. We estimate the function point of two case studies using the COSMIC and IFPUG. Then we insert our estimation result into the formulas to see how close or diverse the output will be in comparison with our calculation. The result varied widely and nothing conclusive can be said, though, two of the formulas give closer estimation range than others. We also highlight why COSMIC may be more desirable today than the IFPUG and presented the progress level on trying to establish a convertible relationship between the two methods.