What factors affect the quality of medical students' doctoral theses? A comparative study in affiliated hospitals of a Chinese university.

Background: The quality of doctoral theses decides whether medical PhD and MD candidates could get their doctoral degree successfully. Good quality theses could be rewarded by Peking University which is a great honor for both doctoral candidates and for mentors. The present study aims to determine factors affecting the quality of medical doctoral theses. Methods: Honored theses and nonhonored theses were matched 1:3 randomly by specialty and submission year. Conditional logistic regressions were utilized. Results: Five domains comprising 17 indicators were put forward to evaluate the quality of doctoral theses. 41 honored theses and 119 matched nonhonored theses from years 2012-2016 were analyzed by univariate and multivariate conditional logistic regression. Degree type (OR: 107.56, 95%CI: 1.20-9632.70, P=0.041), first author impact factor (OR:1.24, 95%CI: 1.01-1.53, P=0.040) and correctly reported statistic results (OR: 43.18, 95%CI: 1.88-991.61, P=0.019) are independent factors influencing the quality of a doctoral thesis. Conclusions: The present study indicates that there is a significant gap between PhD and MD students on quality of thesis. The rewarded theses have a feature of high first author impact factor. However, most medical students need more training on statistics to improve the quality of their doctoral theses.