This paper proposes a new application of Stochastic Frontier Analysis (SFA) for estimating the student performance gap and how this can be used to assess changes of teaching quality at the individual unit-of-study level (module-level). Although there have been other examples in the literature that assess 'efficiency' in student outcomes, this is the first study that proposes the use of SFA specifically at the module level and with the goal of creating an aggregate measure of 'quality', thus avoiding the known issue of the statistical inconsistency of unit-specific SFA estimates. A case study is presented on how the approach can be applied in practice, with discussion on potential implementation issues. This paper is targeted to academics and policy makers that are interested in the quantitative assessment of student outcomes and specifically to those who want to assess how changes in module structure and/or delivery have affected said student outcomes.