AbstractThe Sustainable Development Goals (SDGs) purport to cleanly separate politics and technical matters, embodied by the political negotiation of goals and targets, and the technical creation of an indicator framework. This article analyses how this boundary between science and politics is managed in practice. The statisticians tasked with selecting indicators through the Inter‐agency and Expert Group on Sustainable Development Goal Indicators (IAEG‐SDGs) are seconded to a global process from national statistical offices. Boundary management requires acceptance of certain normative and political aspects of creating an indicator framework, such as claims to national relevance. Others, like overt national intervention, are however considered impermissible. Each statistician must manage their role as a boundary expert that experience irresolvable tensions due to representing specific countries while being mandated to propound scientific practices and norms. Building on this empirical inquiry, the article sketches out a new normative ideal for knowledge pluralism in the measurement of sustainable development. It argues that indicator processes would benefit from more pluralistic indicator bodies than the IAEG‐SDGs. Including diversified knowledge and perspectives from civil society and international organisations would explicate already existing political contestation. It would also contribute to capturing more of the complexities of sustainable development in future monitoring frameworks through consideration of a broader selection of methodologies.