Assessing the Maintainability Benefits of Design Restructuring Using Dependency Analysis

Software developers and project managers often have to assess the quality of software design. A commonly adopted hypothesis is that a good design should cost less to maintain than a poor design. In this paper, we propose a model for quantifying the quality of a design from a maintainability perspective. Based on this model, we propose a novel strategy for predicting the “Return on Investment” (ROI) for possible design restructurings using procedure-level dependency analysis. We demonstrate this approach with two exploratory Java case studies. Our results show that common low-level source code transformations change the system dependency structure in a beneficial way, allowing recovery of the initial refactoring investment over a number of maintenance activities.