Measuring refactoring benefits: a survey of the evidence

Refactoring has become a standard technique for software developers to use when trying to improve or evolve the design of a program. It is a key component of Agile methods, the most popular family of software development methodologies in industrial practice. Refactoring has also been the subject of much attention from researchers and many practitioner textbooks have been written on the topic. It would be natural to assume then that the benefits of refactoring would be easy agree upon, and easy to measure. In this position paper we review a selection of the empirical studies that have attempted to measure the benefits of refactoring and find the situation to be quite unclear. The evidence suggests that what motivates developers to refactor, and what benefits accrue from refactoring, are open issues that require further research.