Sustainability transitions require shifts in multiple social systems, practices, and institutions. Different innovation perspectives are essential for achieving and understanding transitions. They range from actor-oriented (organizational innovation management, regional innovation ecosystems) to mode-oriented (responsible innovation, mission-driven innovation) to process-oriented (social innovation) perspectives. For sustainability transitions to be governed, we need a better understanding of how the relevant contributions of innovations can be measured. In this article, we review the status of measurement across the different innovation perspectives. We find that measurement status becomes weaker as we move from actor-oriented to process-oriented innovations. To address this shortcoming, we then develop a conceptual approach for measuring social innovation. Thereby, we integrate organizational innovation capacities and regional contexts with the transformational elements of social innovation. We discuss how such an integrated and multi-level approach to measurement enhances our understanding of social innovations and, in particular, their contributions to sustainability transitions. We contribute to the sustainability transitions literature by tying it to different innovation perspectives and by conceptualizing new innovation mechanisms that drive transformations. We add to social innovation theory by specifying its role in change toward sustainability and advancing it to a measurable construct relevant to governance and policymaking.
