More than policy neutral: Justifying the power of science-policy interfaces through legitimacy

Science-policy interfaces are influential institutions that support policymakers in addressing complex environmental challenges. However, the power that SPIs wield in this capacity has been largely overlooked by the existing literature, which has primarily focused on the effectiveness of SPIs, often portraying them as apolitical and policy-neutral institutions. Drawing on an integrative literature review, this article proposes a shift from effectiveness towards justifying the power of SPIs through assessing their legitimacy. We develop a framework for enhancing the democratic and epistemic quality of SPIs that comprises 12 criteria across the three dimensions of input, throughput, and output legitimacy. Input legitimacy criteria include inclusivity, consideration of multiple knowledge systems, and transdisciplinarity. Throughput legitimacy criteria address process accessibility, transparency, reflexivity, conflict management, and accountability. Output legitimacy criteria cover efficacy, accessibility, understandability, and dissemination. The article provides a pathway for SPIs to foster both knowledge-based and participatory decision-making, by providing scholars and practitioners an evaluative tool to bridge the potential tensions between expertise and democratic representation in environmental governance.