- Research-based knowledge: Scientific knowledge is perceived as highly credible and therefore used to underline certain positions in the policy process, it has however some shortcomings:
- It may take too long for the pace of policy design
- Scope and coverage may be too small
- Project and policy implementation knowledge: Knowledge generated during the implementation of policy implementation projects and programmes are a very valuable source, because of its practical orientation.
- Statistics: Statistical information (as it is) plays an important role in the policy modelling process, because of its “objective” character. It is also a very important input for simulations and forecasts.