Large studies reveal how reference bias limits policy applications of self-report measures.

There is growing policy interest in identifying contexts that cultivate self-regulation. Doing so often entails comparing groups of individuals (e.g., from different schools). We show that self-report questionnaires-the most prevalent modality for assessing self-regulation-are prone to reference bias, defined as systematic error arising from differences in the implicit standards by which individuals evaluate behavior. In three studies, adolescents (N = 229,685) whose peers performed better academically rated themselves lower in self-regulation and held higher standards for self-regulation. This effect was not observed for task measures of self-regulation and led to paradoxical predictions of college persistence 6 years later. These findings suggest that standards for self-regulation vary by social group, limiting the policy applications of self-report questionnaires.