The need for decisions on health policies, programmes and practice to be informed by evidence is indisputable. The current debates are around types and grades of evidence, techniques for knowledge appraisal, management and uptake, and on the varying needs of different decision making purposes and contexts. What is clear is that to inform decision-making the best available evidence must be found and then applied. This evidence review acknowledges three main types of knowledge, and the wealth of experiential knowledge from country programmes.