"I got here through my own effort": dental students' attribution of their own success and their judgements about a socio-economically disadvantaged applicant

This is the preregistration of a secondary analysis of existing survey data. The analysis plan was locked on 1 November 2026 and deposited here before any analysis relating the exposure to the outcomes was carried out. The study uses an online survey of 500 undergraduate dental students from seven Korean dental schools, conducted in May 2024 (Institutional Review Board of the Seoul National University School of Dentistry, S-D20240015). It asks whether students who attribute their admission to dental school mainly to their own effort or talent (internal attribution), rather than to support from society, school or family, are less likely to favour a socio-economically disadvantaged applicant in two vignette questions: who should receive an admission place, and who will later become a dentist who advocates for oral health rights. The primary analysis is a proportional-odds model of the number of times the disadvantaged applicant is chosen (0–2), adjusted for school, year of study, sex, age and grade point average. The two vignette items are co-primary outcomes, with Holm adjustment. The document specifies the hypotheses, variables with their original Korean wording, exclusions, sensitivity analyses, exploratory moderators and inference criteria. It also discloses all information the analysts had seen beforehand, which was limited to univariate distributions and permuted-outcome code checks.