This report synthesizes key findings and insights from the Compendium of Evidence on the Effectiveness of Innovation Policy Intervention Project. The Compendium compiles and appraises available evidence about the impacts of a range of innovation policies. The purpose of this report is twofold. First, it pulls together overall lessons regarding the effectiveness and impacts of the innovation support measures covered in the Compendium. Second, the report offers observations and insights about the state of evidence and its production on the effectiveness of policies in this domain, including a consideration of evaluation methods, approaches and gaps. This provides a basis for deliberation on improved policy design and implementation as well as the production of evidence to support innovation policy making in the future.