AbstractThis meta‐analysis tested a series of moderators of sex‐ and race‐based subgroup differences using assessment center (AC) field data. We found that sex‐based subgroup differences favoring female assessees were smaller among studies that reported: combining AC scores with other tests to compute overall assessment ratings, lower mean correlations between rating dimensions, using more than one assessor to rate assessees in exercises, and providing assessor training. In contrast, we found larger sex‐based subgroup differences favoring female assessees among studies that reported: lower proportions of females in assessee pools, conducting a job analysis to design the AC, and using multiple observations of AC dimensions across exercises. We also observed a polynomial effect showing that subgroup differences most strongly favored female assessees in jobs with the highest and lowest rates of female incumbents. We found race‐based subgroup differences favoring White assessees were smaller on less cognitively loaded rating dimensions and for jobs with lower rates of Black incumbents. Studies reporting greater overall methodological rigor also showed smaller subgroup differences favoring White assessees. Regarding specific rigor features, studies reporting use of highly qualified assessors and integrating dimension ratings from separate exercises into overall dimension scores showed significantly lower differences favoring White assessees.