The Promotion Wall: Efficiency-Equity Trade-offs of Direct Promotion Regimes in Engineering Education

Progression and assessment rules are often treated as administrative details, yet they fundamentally shape who is allowed to remain in higher education, and on what terms. This article uses a calibrated agent-based model to examine how alternative progression regimes reconfigure dropout, time-to-degree, equity and students' psychological experience in a long, tightly sequenced engineering programme. Building on a leakage-aware longitudinal dataset of 1,343 students and a Kaplan-Meier survival analysis of time-to-dropout, we simulate three policy scenarios: (A) a historical "regularity + finals" regime, where students accumulate exam debt; (B) a direct-promotion regime that removes regularity and finals but requires full course completion each term; and (C) a direct-promotion regime complemented by a capacity-limited remedial "safety net" for marginal failures in bottleneck courses. The model is empirically calibrated to reproduce the observed dropout curve under Scenario A and then used to explore counterfactuals. Results show that direct promotion creates a "promotion wall": attrition becomes sharply front-loaded in the first two years, overall dropout rises, and equity gaps between low- and high-resilience students widen, even as exam debt disappears. The safety-net scenario partially dismantles this wall: it reduces dropout and equity gaps relative to pure direct promotion and yields the lowest final stress levels, at the cost of additional, targeted teaching capacity. These findings position progression rules as central objects of assessment policy rather than neutral background. The article argues that claims of improved efficiency are incomplete unless they are evaluated jointly with inclusion, equity and students' psychological wellbeing, and it illustrates how simulation-based decision support can help institutions rehearse assessment reforms before implementing them.