Differences in the Definition and Calculation of the LOC Metric in Free Tools∗

The software metric LOC (Lines of Code) is probably one of the most controversial metrics in software engineering practice. It is relatively easy to calculate, understand and use by the different stakeholders for a variety of purposes; LOC is the most frequently applied measure in software estimation, quality assurance and many other fields. Yet, there is a high level of variability in the definition and calculation methods of the metric which makes it difficult to use it as a base for important decisions. Furthermore, there are cases when its usage is highly questionable – such as programmer productivity assessment. In this paper, we investigate how LOC is usually defined and calculated by today’s free LOC calculator tools. We used a set of tools to compute LOC metrics on a variety of open source systems in order to measure the actual differences between results and investigate the possible causes of the deviation.