Cross-cultural validation and standardization of the Impostor-Profile 30

Abstract The impostor phenomenon describes a maladaptive personality style marked by persistent self-doubt and fear of being exposed as a fraud despite evident success. Despite its global relevance, the construct’s cross-cultural measurement invariance has not yet been empirically established. This study assessed the measurement invariance of the Impostor-Profile 30 across six European countries ( N = 2472; 60.0% female; M age = 31.34, SD = 13.36), and standardized the instrument by deriving normative values. Multi-group confirmatory factor analyses supported partial scalar invariance across five countries (excluding Italy; CFI = 0.897, RMSEA = 0.060, SRMR = 0.090), strict invariance across genders (CFI = 0.932, RMSEA = 0.051, SRMR = 0.057), and metric invariance across age groups (CFI = 0.915, RMSEA = 0.055, SRMR = 0.070). Age-specific percentile ranks were derived to enable norm-based interpretation. These results confirm the cross-cultural equivalence of the IPP across five European countries, supporting its standardized use in psychological research and practice.