This report sets out a conceptual map for potential elements of a science-for-policy advisory ecosystem. The aim of this map is not to propose an ideal system, but rather to highlight how elements need to connect with each other at multiple levels; to allow us to ask how all involved in evidence production, mobilisation and use can act to support more effective system functioning. This paper assumes that the goal of a science-for-policy system is the delivery of relevant, robust evidence to people with the capacity to absorb and fully understand it, in order that it might inform their decision-making. The proposed indicators therefore help identify opportunities for support, intervention, and more strategic use of resources to improve supply and demand of evidence.