A widely used qualitative research technique, the semi-structured interview consists of a verbal interaction solicited by the interviewer from a respondent, based on a grid of questions used in a very flexible manner. The interview aims both to collect information and to give an account of the person's experience and view of the world, from a comprehensive perspective. It is useful for various types of public policy evaluations, including clarifying the objectives of a policy, analysing its implementation or studying its reception.