Survival Analysis of Time-to-Completion for Postgraduate Students in Nigerian Universities Using Competing Risks Models

Postgraduate student attrition and delayed programme completion impose significant costs on Nigerian universities and individual students, yet survival analysis of time-to-completion accounting for competing risks (graduation versus dropout) has not been applied to Nigerian university data. This study applies competing risks survival analysis to model time-to-completion among Masters and PhD students in five Nigerian universities spanning the South West (University of Lagos), North West (Bayero University Kano), South East (University of Nigeria Nsukka), North Central (University of Abuja), and South South (University of Port Harcourt) zones. Administrative records for 820 postgraduate students who enrolled from 2015 to 2018 and were tracked to 2023 were used. Cause-specific hazard models and Fine-Gray subdistribution hazard models estimated graduation and dropout hazards separately. Cumulative incidence functions were compared across student and institution characteristics. Median time to completion was 5.2 years for Masters and 7.8 years for PhD students. Seven-year completion rates were 54 percent for Masters and 41 percent for PhD. Fine-Gray subdistribution hazard regression showed that studentship funding significantly increased graduation hazard (SHR = 2.1, p < 0.001) while reducing dropout (SHR = 0.38). Programme supervision ratio below 1:10 was associated with faster graduation. Public university affiliation compared to private was associated with longer median completion time. The study provides competing risk evidence for Nigerian postgraduate programme improvement and recommends funding expansion, supervision ratio standards, and annual doctoral progress review mandates. Keywords: competing risks survival analysis, postgraduate completion, Nigerian universities, Fine-Gray model, time-to-degree