Well chosen and well implemented methods for data collection and analysis are essential for all types of evaluations. This brief provides an overview of the issues involved in choosing and using methods for impact evaluations – that is, evaluations that provide information about the intended and unintended long term effects produced by programmes or policies.
Main points Data collection and analysis methods should be chosen to match the particular evaluation in terms of its key evaluation questions (KEQs) and the resources available. Impact evaluations should make maximum use of existing data and then fill gaps with new data. Data collection and analysis methods should be chosen to complement each other’s strengths and weaknesses.