The Usability (or Not) of Refactoring Tools

Although software developers typically have access to numerous refactoring tools, most developers avoid using these tools despite their benefits. Researchers have identified many reasons for the disuse of refactoring tools, including a lack of awareness by the developers, a lack of predictability of the tools, and a lack of need for the tools. In this paper, we build on this earlier work and employ the ISO 9241-11 definition of usability to develop a theory of usability for refactoring tools. We investigate existing refactoring tools using this theory by analyzing how 17 developers experience refactoring tools in three software change tasks we asked them to perform. We analyze qualitatively the resulting interview transcripts based on our theory and report on a number of observations that can inform tool designers interested in improving the usability of refactoring tools. For instance, we found a desire for developers to guide how a refactoring tool changes the code and a need for refactoring tools to describe changes made to developers. Refactoring tools are currently expected to preserve program behavior. These observations indicate that it may be necessary to give developers more control over this property, including the ability to relax it, for the tools to be usable; that is, for the tools to be effective, efficient and satisfying for the developer to employ.