Financial investment in undergraduate tuition and institutional performance on the National Medical Examination in Metropolitan Lima, Peru: an ecological correlational study

Objectives Medical faculties in Metropolitan Lima operate under heterogeneous pricing structures, raising questions as to whether higher tuition expenditure correlates with superior standardized clinical competence. This study evaluated the association between cumulative financial investment in undergraduate tuition and institutional performance on the National Medical Examination (ENAM) between 2021 and 2024. Methods An ecological, cross-sectional, institutional-level correlational study was conducted across all 11 licensed medical faculties in Metropolitan Lima participating continuously in the ENAM (2021–2024). Data were retrieved from official registries of SUNEDU and DIGEP-MINSA. Bivariate associations between cumulative 7-year tuition costs and consolidated ENAM scores were evaluated using Pearson's r and Spearman's rank correlation ( ρ ). Stratified analyses restricted to the private sector ( n = 9) and sensitivity analyses excluding truncated cohorts ( n = 10) were performed. Results Cumulative tuition costs ranged from S/ 509.60 ($135.89 USD) in public universities to S/ 430,780 ($114,875 USD) in the private sector. Across the total institutional census ( N = 11), cumulative tuition exhibited a moderate monotonic association with consolidated ENAM performance ( ρ 0.655, p = 0.029), while parametric linearity was non-significant (r = 0.596, p = 0.053) due to state-funded institutions (notably UNMSM: 14.49 ± 1.45 points; S/ 2,604) achieving top-tier scores at marginal direct costs. Within the private sector ( n = 9 ), the association strengthened markedly ( ρ = 0.850 , 95% CI [0.43, 0.97], p = 0.004 ; Pearson r = 0.887 , p = 0.001 ). Sensitivity analysis excluding truncated cohorts confirmed consistent rank correspondence ( ρ = 0.952 , 95% CI [0.75, 0.99], p < 0.001 ). Conclusions Cumulative financial investment in private medical education in Metropolitan Lima is positively associated with institutional performance on the ENAM, whereas the public sector achieves high standardized outcomes through state subsidization and rigorous admission selectivity. These findings provide preliminary exploratory evidence to promote financial transparency in higher education and inform policy discussions regarding institutional accountability and educational quality oversight.