8.25 There is no single way to undertake process evaluations, action research or case studies.They are very broad types of evaluation design in which analysts, in consultation with policy makers, can choose a variety of methods to answer the particular research questions, considering the timescales, resources and data available. As well as considering the immediate questions that a policy maker might want to answer about the implementation and delivery of a policy, it will also be important to consider whether an impact and/or economic evaluation will also be conducted. If so, then in the planning stage, consideration should also be given to what data might be required to inform, and explain the results of, the impact evaluation and how the delivery and implementation evaluation could collect relevant data.