The Pushback Effects of Race, Ethnicity, Gender, and Age in Code Review

Code review is a common practice in software organizations, where software engineers give each other feedback about a code change. As in other human decision-making processes, code review is susceptible to human biases, where reviewers’ feedback to the author may depend on how reviewers perceive the author’s demographic identity, whether consciously or unconsciously. Through the lens of role congruity theory, we show that the amount of pushback that code authors receive varies based on their gender, race/ethnicity, and age. Furthermore, we estimate that such pushback costs Google more than 1000 extra engineer hours every day, or about 4% of the estimated time engineers spend responding to reviewer comments, a cost borne by non-White and non-male engineers.

• Human-Computer Interaction and Visualization

• Software Engineering