Because developers significantly impact software development projects, many researchers have studied developers as a means to improve the quality of software. However, most works have examined developers in a single project, and research involving multiple projects has yet to be published. Herein we propose an analysis method which investigates whether an evaluation of developers based on individual experience is feasible when targeting more than one project by the same organization transversely. Our method deals with the logs of the version control system and the bug tracking system. To support this method, we also propose two models to evaluate developer, the defect removal overhead rate (DROR) and developer's experience point (EXP). The results reveal the following. 1) DROR cannot be used to compare different projects in the same organization. 2) There is certainly a difference in DROR's between experienced and inexperienced developers. 3) EXP should be a useful model to evaluate developers as the number of projects increases. The data obtained from our method should propose the personnel distribution measures within the development framework for future developments, which might lead to improve the quality of software.