8.1 As has been discussed earlier, evaluation is not something that happens only after a policy has been implemented. Evaluation can be used throughout the life of a policy to provide policy makers with timely feedback about whether a policy is being implemented as expected, whether important outputs are being delivered and if there are any parts of the policy which are not working or which are working particularly well. Process evaluation, action research and case studies provide evaluation evidence on the implementation and delivery of policy which provides policy makers with the opportunity to refine and improve policies to help them have the best chance of achieving their ultimate aims. This chapter will describe the three evaluation approaches, presenting their similarities and differences, and describe the range of research methods used in these approaches, and key principles to consider when deciding which method/s to use.