Peer Code Review in Research Software: Practices, Improvements, and Implementation Challenges from Interviews of RSEs
The quality of research software directly impacts the quality of the research results. Peer code review can identify defects, improve design, and facilitate knowledge sharing. Previously, we conducted a survey to understand how Research Software Engineers (RSEs) view and use code review. Because the prior survey did not examine how RSEs implement code review or the challenges they face, we study here how RSEs implement code review improvement practices, the challenges that limit adoption, and the additional strategies they propose. To gather this insight, we conducted 20 semi-structured interviews of RSEs. The results show that RSEs most often improved code review by using pull requests, defining review expectations, adding lightweight process steps, and using tools and automation (e.g., CI checks) to reduce effort and increase consistency. Key challenges included limited reviewer capacity and time, gaps in Git and software engineering skills, social and authority barriers to setting norms, and weak documentation or enforcement of standards. They also proposed lightweight training, clearer reviewer guidance (e.g., checklists), and better recognition of review and mentoring work. To ease peer code review adoption in research software, teams should begin with lightweight pull-request workflows, document a few clear review rules, use CI to enforce basics, and support reviewers with simple guidance, training, and recognition.