Enayat A. Moallemi , Fateme Zare, Aniek Hebinck, Katrina Szetey, Edmundo Molina-Perez, Romy Zyngier, Michalis Hadjikakou , Jan Kwakkel, Marjolijn Haasnoot, Kelly K. Miller, David Groves, Brett A. Bryan

Decision-making under uncertainty is important for managing human-natural systems in a changing world. A major source of uncertainty that challenges decisions is rooted in their multi-actor settings, i.e., the poorly understood societal actors with diverse values, complex relationships, and conflicting management approaches. Despite general agreement across disciplines on co-producing knowledge for viable and inclusive outcomes in multi-actor settings, there is still limited conceptual clarity and no systematic understanding on what co-production means in decision-making under uncertainty and how it can be achieved. Here, we use content analysis and clustering to systematically analyse 50 decision-making cases with multiple time and spatial scales across 26 countries and in 9 different sectors in the last decade to serve two aims. The first is to synthesise the key recurring approaches that underpin high quality decision co-production across many cases of diverse features. The second is to identify important deficits and opportunities to leverage existing approaches towards flourishing co-production in supporting decision-making. We find that four general approaches emerge centred around: promoting innovation for robust and equitable decisions; broadening the span of co-production across interacting systems; fostering social learning and inclusive participation; and improving pathways to impact. Additionally, five key areas that should be addressed to improve decision co-production are identified in relation to: participation diversity; social learning; power relationships; governance inclusivity; and transformative change. Characterising the emergent approaches and their key areas for improvement can help guide future works towards more pluralistic and integrated science and practice.