Measuring the maintainability of open-source software

An editorial in Empirical Software Engineering suggested that open-source software projects offer a great deal of data that can be used for experimenta-tion. These data include artifacts such as source code and defect reports. In this paper we show that sources of open-source maintenance data, such as defect-tracking systems, change logs, and source code, can-not, in general, be used for measuring maintainability. We further show that approaches such as using defect distributions and the average lag time to fix a defect can be equally unusable. We conclude that, despite the plethora of open-source maintenance data, it is ex-tremely hard to find data for determining the main-tainability of open-source software. 1