This article develops the current international research examining the role of think tanks and analytical communities in policy making, led by Research Committees of the International Political Science Association “Comparative public policy”. In this article the authors propose methodology of analytical communities’ policy impact assessment. This methodology is based on the study of International and Russian experience. The Methodology was tested on the example of sectoral centers of scientific and technological forecasting developed currently in Russia. These centers have developed a unique expertise and materials in the field of science, technology and innovation policy. The further development of the centers of scientific and technological forecasting will fill the gap of the lack of expertanalytical support of both public authorities responsible for lementation of STI policy, and scientists engaged in innovative scientific discoveries. An important component of an effective development of the activities of the analytical community is to develop their own autonomy and consolidated action on innovation. The proposed methodology can be applied on a regular basis to assess the effectiveness of the centers of scientific and technological forecasting network, to monitor their activities, and to assess the impact on policy changes of other public policy actors.