Effects of explicit feature traceability on program comprehension

Developers spend a substantial amount of their time with program comprehension. To improve their comprehension and refresh their memory, developers need to communicate with other developers, read the documentation, and analyze the source code. Many studies show that developers focus primarily on the source code and that small improvements can have a strong impact. As such, it is crucial to bring the code itself into a more comprehensible form. A particular technique for this purpose are explicit feature traces to easily identify a program’s functionalities. To improve our empirical understanding about the effects of feature traces, we report an online experiment with 49 professional software developers. We studied the impact of explicit feature traces, namely annotations and decomposition, on program comprehension and compared them to the same code without traces. Besides this experiment, we also asked our participants about their opinions in order to combine quantitative and qualitative data. Our results indicate that, as opposed to purely object-oriented code: (1) annotations can have positive effects on program comprehension; (2) decomposition can have a negative impact on bug localization; and (3) our participants perceive both techniques as beneficial. Moreover, none of the three code versions yields significant improvements on task completion time. Overall, our results indicate that lightweight traceability, such as using annotations, provides immediate benefits to developers during software development and maintenance without extensive training or tooling; and can improve current industrial practices that rely on heavyweight traceability tools (e.g., DOORS) and retroactive fulfillment of standards (e.g., ISO-26262, DO-178B).