8.2 A number of different evaluation designs can be used to understand the implementation and/ or delivery of a policy. As discussed in Chapter 5, choosing the most appropriate design will be dependent on a number of factors including the types of research question that need to be answered, how a policy has been delivered (e.g. national roll out or pilot) and practical issues such as when evidence is needed and what resources are available. The most common types of research that might be used to evaluate the implementation and delivery of policy are process evaluations, action research and case studies.