A mathematical model used to establish optimal locations. The model takes account of the location and demand of the customers, the capacity of the facilities, and operational and transport costs. Rushton (1988) Econ. Geo. 64, 2 provides an easily comprehensible discussion of the use of a location-allocation model to provide ‘an explicit framework for diagnosing accessibility problems, measuring the efficiency of location decisions and the current levels of settlement efficiency [and the] generation of viable alternatives for action by decision makers’. A more technical, but still admirably clear, report on the use of location-allocation models in planning health care in Ghana is provided by Møller-Jensen and Kofie (2001) Geografisk Tidsskrift 101. See Hodgson (1988) Soc. Sci Med. 26, 1, 153 on an hierarchical location-allocation model for primary health care delivery in Goa.