Uganda's 2019 lower secondary curriculum reform repositioned geography as an optional subject, a decision justified by learner-centred pedagogy but contested on grounds of national coherence. the present analysis argues that the reform's most consequential effect may lie not in classroom practice but in the institutional accountability architecture that governs curriculum implementation. Drawing on principal-agent theory and the institutional logics perspective, the analysis theorises how subject optionality alters the information environment available to district education officers, school inspectors and head teachers, thereby reshaping their capacity to monitor curriculum fidelity. Because no empirical data are presently available, the contribution is theoretical and methodological: it specifies a causal mechanism, derives testable propositions, identifies necessary data sources and discusses threats to identification including spillover effects and selective enrolment. The proposed design offers a template for evaluating curriculum reforms as institutional interventions rather than purely pedagogical ones, with implications for education governance research in low-income contexts.