The document discusses different theories of how evidence informs policy processes. The traditional linear model of research directly leading to policy changes is now recognized as oversimplified, as it ignores political contexts and competing demands. A more realistic iterative model sees policymakers using research to expand options rather than passively receiving information. A third approach focuses on interactions between actors and networks. The document also notes that identifying the target policy process stage and understanding differing notions of evidence between researchers and policymakers are important practical considerations for researchers seeking to inform policy.