Assessing societal effects: Lessons from evaluation approaches in transdisciplinary research fields

Achieving societal effects is crucial for transdisciplinary research. In this article, we present key characteristics of impact evaluation of transdisciplinary research. We compare different approaches in sustainability, public health, and development research to advance joint learning and define common challenges.To address complex societal problems, transdisciplinary approaches are increasingly being employed in research to achieve both scientific and societal effects. Comparing experiences of different impact evaluation approaches enables mutual learning across research fields. We provide an overview of the key characteristics of different approaches to assess the impact of transdisciplinary research across the fields of public health, development, and sustainability; uncover commonalities and challenges in applying these approaches; and suggest how they can be overcome by drawing on examples from specific approaches and fields. We find commonalities in terms of conceptual framing as well as data collection and analysis from which we derive the following key challenges:1. evidencing causal claims, 2. including multiple perspectives on effects, and 3. sustaining continuous monitoring and evaluation. We conclude that impact evaluation of transdisciplinary research must capture the interplay and effects of multiple actors, processes, and impact pathways to promote learning and empirical rigour and suggest how funders can support this endeavour.