Measuring prejudice and stereotypes: A systematic review of psychometric quality and conceptual foundations.

Prejudice and stereotypes are central constructs in social psychology, yet instruments used to measure them vary in conceptual clarity and psychometric evidence. This preregistered systematic review provides a comprehensive, cross-method synthesis of the psychometric properties and theoretical foundations of measures assessing racial and ethnic prejudice and stereotypes. Following PRISMA and COSMIN guidelines, we screened 13,363 records and included 263 studies published between 1951 and 2024. We evaluated reliability, validity, factor structure, measurement invariance and conceptual alignment across explicit, implicit and behavioural instruments. Findings indicate a methodologically diverse but psychometrically fragile field. Most measures were developed with US samples, rarely assessed temporal stability or predictive validity, and often provided limited evidence of theoretical-empirical coherence. Only 4% of instruments reached high-quality evidence under the GRADE framework, while most showed substantial inconsistency and risk of bias in the available evidence. Conceptually, only one-third of studies clearly defined prejudice, and most operationalized it narrowly at the cognitive, individual level, with less attention to affective and behavioural dimensions. Overall, conceptual ambiguity and uneven validation evidence complicate cumulative interpretation. We call for clearer definitions, multimethod integration and transparent practices to develop psychometrically rigorous, theoretically coherent and culturally sensitive tools for capturing prejudice as a dynamic, multidimensional phenomenon.