Authors: Droste, Nils; D'Amato, Dalia ;Ekström, Hanna;Iliev, Bogomil Emilov ;Thomsen, Marianne;

To inform the design of policies that effectively reach sustainable development goals, reliable knowledge about both the status quo and potential pathways of transition is required. A comprehensive evidence-based policy advice thus needs to capture dynamics of complex socio-ecological systems, including biophysical mechanisms and diverse human-nature relationships. We present a conceptual framework for a transdisciplinary, co-productive approach for evaluating outcomes of land-use governance through an integrated policy assessment. The case of Nordic forest policies is used to elaborate on the role of theory, model integration, and knowledge co-production. Here, we argue that three main components are needed: 1) a comprehensive theory about causal mechanisms in the system, 2) a modular architecture that operationalizes data flows between various models, and 3) a procedure to integrate values and knowledge from multiple stakeholders. The general idea of such a modular model architecture for integrated policy assessments can in principle be applied to any land use policy nexus.