The role and impact of diversity in higher education has permeated conversations about student access and achievement for many years. Language articulated by various courts suggests that higher education policies should reflect a broad conceptualisation of diversity beyond that of the magnitude and proportion of race and ethnicity, yet institutions struggle to measure diversity in a manner that effectively supports the management of diversity goals and meets the legal requirements for targeted strategies. Building on methodologies from biology and political science, this paper proposes a new way of conceptualising and measuring diversity that addresses the limitations of traditional diversity metrics and accounts for race and race-neutral attributes within a single model. Using data from over 1500 colleges and universities, the development of a composite diversity index is demonstrated as a strategy for meeting organisational need to account for and measure multiple diversity attributes.