In this last article in the series the authors focus on the issue of researching and evaluating pharmaceutical policy. The past five articles made an argument for why pharmaceutical policy is important and why it is different from health policy. The evidence base needed for pharmaceutical policymaking is also somewhat specialized in relation to health policy. Taking these differences into consideration the authors provide their definition of pharmaceutical policy. The knowledge base for good pharmaceutical policymaking needs to be broad and include approaches and methodologies ranging from the highly quantitative and experimental to the purely qualitative. Other policy questions such as those concerned with rational use of medicines and economics illustrate that pharmaceutical policy needs more varied approaches than randomized clinical trials alone can provide. The importance of gaining a thorough overview and understanding of the available design and methodological options for policy analysis is emphasized. Research into pharmaceutical policy has many commonalities with evaluation and policy analysis. Some of the main pitfalls that policymakers, researchers and analysts can fall into when formulating and evaluating pharmaceutical policy are discussed and include: using too narrow evaluation questions; choosing inappropriate methods/designs; and the problem of bias and self-censorship. The authors conclude this series by advocating a strong focus on research and an international evaluation culture around pharmaceutical policy. They emphasize the importance of pharmaceutical specialists' (i.e., pharmacists') involvement in pharmaceutical policy analysis and the policy consultative process.