The primary business of interaction-oriented policy research within the framework of actor-centered institutionalism is to explain policy choices and to produce systematic knowledge that may be useful for developing politically feasible policy recommendations or for designing institutions. The implication is that interaction-oriented policy research is more dependent on empirical data that must be collected specifically for each case than might be the case in neoclassical economics. In policy research, the authors dealing mainly with collective and corporate actors, such as political parties, labor unions, government ministries, central banks, or international organizations, rather than with individuals acting on their own account. Institutional design may influence the problem-solving effectiveness of policy processes through rules determining the constitution of actors and their institutional capabilities—which also affect their inclusion, and their strategic options, in the policy-relevant actor constellations. But the actor constellation still describes a static picture rather than the actual interactions producing policy outcomes.