De-identified dataset: Impostor phenomenon in pre-clinical medical students — severity and association with academic achievement

De-identified data underlying a cross-sectional study of impostor phenomenon among 100 pre-clinical medical students (Year 1 and Year 2) at a medical college in Islamabad, Pakistan. The dataset contains item-level responses to the Clance Impostor Phenomenon Scale, total scores, severity categories, year of study, academic achievement group, and self-reported gender. Students were sampled using a purposive, criterion-based approach: within each year, the top 25 and bottom 25 students by overall examination percentage were classified as high and low achievers respectively. Students in the middle of each class were not sampled, so these data support comparison between predefined achievement groups but cannot be used to estimate prevalence in the wider student population. Clance Impostor Phenomenon Scale item wording is copyrighted and is not reproduced; variables are labelled generically. Raw examination percentages are withheld to prevent re-identification of individual students. See the accompanying codebook for full variable documentation.