Planning and policy-making for the development of the post-harvest fisheries sector has been hampered by the lack of practical tools to understand post-harvest fish losses. The Questionnaire Loss Assessment Method (QLAM) is based on a formal questionnaire survey approach to post-harvest loss assessment. Enumerators interview a population sample using a questionnaire focused on post-harvest losses. Data are analysed and presented using appropriate biometric principles. The method produces quantitative data on key aspects of loss such as the type of loss incurred, reasons for loss and the variables which affect loss (such as fishing gear or processing method). It is also used to validate the results of the associated tools Informal Fish Loss Assessment Method (IFLAM) and Load Tracking, over a wide geographical area or within a number of communities.