Purpose: Education is a key institution of modern society, long recognized for its central role in the reproduction of inequities and with the potential to challenge them. Schools behave as their systems are designed. Achieving equity and excellence is not possible through attempts to fix "the school" or educators. Principles of systemic design that incorporate equity and excellence are needed to increase the likelihood of desirable outcomes. Design/methodology/approach: Using the social contract as a design principle, this paper systematically builds an empirical model of school provision aimed at equitable excellence. Findings: Equitable excellence in school provision is possible if choice is available across geolocation and socio-educational (dis)advantage, schools have autonomy over fiscal, personnel and curricular matters, public accountability is linked to academic outcomes and social impact, all moderated by the quality of teaching. Research limitations/implications: Data-driven empirical modelling is particularly attractive to policy makers, systemic authorities and researchers when theory (of all varieties) does not yield the necessary insights to support the functionality and effectiveness of systems to deliver equitable outcomes at scale. Empirical examples can be used to test the explanatory power of the novel model -- and refine it when necessary. Practical implications: The empirical model and threshold question are the genesis of a common language for assessing relevant costs and benefits of initiatives for government and system designers. Significantly, establishing a threshold question and tests of legitimacy and strength to accompany the novel model provides a more principled way of prioritizing the competing demands on public investment in education. Originality/value: Establishing a threshold question and tests for legitimacy and strength to accompany the novel model provides a more principled way of prioritizing the competing demands to accompany.