Team Activities Measurement Method for Open Source Software Development Using the Gini Coefficient

In recent years, open source software (OSS) has made remarkable contributions as social infrastructure. The model of the OSS development (OSSD) team, as seen in the case of GitHub, is becoming the de facto standard. The OSSD team develops source codes for realizing requirements and, further, test codes for testing the source codes. The present study measures the team activity in OSSD, and it includes aspects of software testing activity. Our previous research revealed the characteristic of the OSSD team, which was that the team consists of a small number of enthusiastic contributors (core members) and a large number of small contributors. This characteristic has some inequalities. The Gini coefficient is a well-known economic index used to measure inequality. This study proposes a method to estimate and use an Effort Person-Months metric as an object of the Gini coefficient for software development. In this method, the difference in team activity can be detected more precisely than by the Gini coefficient obtained from the number of commits and the modification amount. We believe that this method covers detecting software testing activities precisely.