IntroductionI. What Is Open Data?II. The Case StudiesMethodologyThe 19 CasesIII. What Is the Impact of Open Data on People’s Lives?Taxonomy of Open-Data ImpactIV. What Are the Enabling Conditions that Significantly Enhance the Impact of Open Data?V. What Are the Challenges to Open Data Making an Impact?The Eight Premises that Determine the Impact of Open DataVI. Recommendations: Toward a Next Generation Open-Data RoadmapRecommendation 1:Focus on and Define Key Problem Areas for Which Open Data Can Add ValueRecommendation 2:Encourage Collaborations Across Sectors (Especially Between Government, Private Sector, and Civil Society) to Better Match the Supply and Demand of Open DataRecommendation 3:Approach and Treat Data as a Form of Vital 21st-Century Public InfrastructureRecommendation 4:Create Clear Open-Data Policies That Are Measurable and Allow for Agile EvolutionRecommendation 5:Take Steps to Increase the Capacity of Public and Private Actors to Make Meaningful Use of Open DataRecommendation 6:Identify and Manage Risks Associated with the Release and Use of Open DataRecommendation 7:Be Responsive to the Needs, Demands, and Questions Generated from the Use of Open DataRecommendation 8:Allocate and Identify Adequate Resources to Sustain and Expand the Necessary Open-Data Infrastructure in a Participatory MannerRecommendation 9:Develop a Common Research Agenda to Move Toward Evidence-Based Open Data Policies and PracticesRecommendation 10:Keep InnovatingKey Remaining Questions