Mining effort data from the OSS repository of developer's bug fix activity
During the evolution of any software, efforts are made to fix bugs or to add new features in software. In software engineering, previous history of effort data is required to build an effort estimation model, which estimates the cost and complexity of any software. Therefore, the role of effort data is indispensable to build state of the art effort estimation models. Most of the Open Source Software does not maintain any effort related information. Consequently there is no state of the art effort estimation model for Open Source Software, whereas most of the existing effort models are for commercial software. In this paper we present an approach to build an effort estimation model for Open Source Software. For this purpose we suggest to mine effort data from the history of the developer's bug fix activities. Our approach determines the actual time spend to fix a bug, and considers it as an estimated effort. Initially, we use the developer's bug fix activity data to construct the developer's activity log book. The log book is used to store the actual time elapsed to fix a bug. Subsequently, the log book information is used to mine the bug fix effort data. Furthermore, the developer's bug fix activity data is used to define three different measures for the developer's contribution or expertise level. Finally, we used the bug fix activity data to visualize the developer's collaborations and the involved source files. In order to perform an experiment we selected the Mozilla open source project and downloaded 93,607 bug reports from the Mozilla project bug tracking system i.e. Bugzilla. We also downloaded the available CVS log data from the Mozilla project repository. In this study we reveal that in case of Mozilla only 4.9% developers have been involved in fixing 71.5% of the reported bugs.