Since 1984, the idea of health equity has proliferated throughout public health discourse with little mainstream critique for its variability and distance from its original articulation signifying social transformation and a commitment to social justice. In the years since health equity’s emergence and proliferation, it has taken on a seemingly endless range of invocations and deployments, but it most often translates into proactive and apolitical discourse and practice. In Margaret Whitehead’s influential characterization (1991), achieving health equity requires determining what is inequitable by examining and judging the causes of inequalities in the context of what is going on in the rest of society. However, it also remains unclear how or if public health actors examine and judge the causes of health inequality. In this article, we take the concept of health equity itself as an object of study and consider the ways in which its widespread deployment has entailed a considerable emptying of its semantic and political content. We point toward equity’s own discursive productivity as well as the quantifying imperative embedded within evidentiary norms that govern knowledge making, and performance management regimes that govern public health practices. Under current conditions of knowledge making and performance evaluation, a range of legitimate action and inaction is produced at the same time that more socially transformative action is legitimately curtailed—not merely by politics, but by the rules of the field in which public health actors work. Ultimately, meaningful progress on a normative ethical idea like health equity will require both substantial philosophical content and an analysis of what is going on in the rest of society.

Since its arrival in 1984, the idea of health equity has proliferated throughout public health discourse with little mainstream critique for its variability and distance from its original definition signifying social transformation and a commitment to social justice. Few researchers have taken the concept itself as an object of study, and no one has analysed how or why health equity has been able to travel so far from its originator, Margaret Whitehead's definition. In Whitehead's words, achieving health equity requires determining what is inequitable by examining and judging the causes of inequalities 'in the context of what is going on in the rest of society'. In the years since health equity's emergence and proliferation, it has taken on a seemingly endless range of invocations and deployments, but it most often translates into proactive and apolitical discourse and practice. This thesis examines the highly variable deployment of health equity in Canadian public health discourse and practice, but it also provides a theoretical account for its successful journey from its original commitment to social justice vis-à-vis injustice. By theorizing health equity as an empty signifier and as a vehicular idea, I show how the concept is invoked within an infinitely extendable field of discourse and practice. Secondly, I analyse how health equity-as an empirical phenomenon and practice-is made knowable through modes of measurement and representation used in Canadian public health organizations. I argue that possibilities for understanding and acting upon health (in)equity are shaped and limited by evidentiary norms embedded in the rules of institutional fields. I historicise these evidentiary norms-which include both imperatives and practices-as mechanisms of government which date back to the enlightenment. By legitimizing and deploying action according to scientific evidentiary productivity rather than normative-political reasoning, government can efface itself. This thesis examines the relationship between precise but incomplete knowledges and justice. However precise our knowledge is, if we do not engage with its incompleteness, we will always miss the mark, and inequities will persist.