Evidence-based policies require data and information on determinants, trends, and consequences of ongoing development processes. This data and information must be conveyed to policy makers. Thus a mechanism is needed to reach them and equip them with arguments for or against specific policy options. This mechanism is to be incorporated into the system of monitoring, analyzing, planning, and managing development processes. This article presents a brief outline of how the project “Development Trends of Mazovian Region” (DTMR) implemented in the years 2009-20014 related to regional policy formulation in terms of building an information base for diagnostic purposes, preparing instruments for modeling and scenario building, networking and lobbying for institutional arrangements that would foster cooperation among researchers and practitioners, both planners and policy makers. The DTRM project was co-financed by the European Union under the European Social Fund and managed by the Mazovian Office for Regional Planning.