2604.01212 Diff Size Alone Explains Less Than 15% of Code Review Duration Variance: A Reanalysis of Four Open-Source Projects
A pervasive assumption in software engineering practice is that code review duration scales primarily with diff size, measured as lines added plus lines deleted. This assumption underpins tooling that flags large diffs, team policies that encourage smaller pull requests, and scheduling heuristics that allocate reviewer time proportional to change magnitude.