This chapter is a critical questioning on the philosophical basis and implication of measuring justice on the basis of social indicators. It tackles the ontological, epistemological, and normative issues of translating complicated moral values into quantitative versions. Presenting an argument holding that justice is a qualitatively thick and second-order value, the chapter discusses the dangers of reification, epistemic exclusion, and depoliticization inherent in indicator-centric governance. It builds on the examples of Amartya Sen, Nancy Fraser, and Nancy Cartwright, suggesting a normative practical theory of justice metrics in terms of pluralism, reflexivity, contestability, and epistemic humility. It also promotes the observation that criteria should be subordinate to the democratic procedures of public reasoning and moral imagination; the indicators should be seen as tools of democratic deliberation and not technocratic closure. By so doing, the chapter retrieves measurement as a potentially transformative, not at all reductive, exercise in public ethics, preparing the ground on which the last chapter can be built: justice-making measures of future societies.