Economic approaches to the third sector: The contributions and limitationsof neo-classical analyses.

The third sector has intrigued, and still does, economists who have used th e neo-classical theory to conduct studies of it. Various approaches in the literature in English are discussed. From a viewpoint initially adopted to explain market phenomena, they try to account for the presence and relative efficiency of non-profit organizations in the service sector. Two major ty pes of approaches are distinguished: a) demand theories (the theory of soci al efficiency and the theory of organizations) that inquire into the reason s why actors - consumers or public authorities, for example - resort to non -profit organizations; b) supply theories that try to justify recourse to n on-profit organizations as a 'mode of productive organization' by raising q uestions about information, the opportunism of actors and the specific natu re of 'collective goods'. The scope of these approaches is assessed; and th e limitations and contradictions of an analytical framework stretched far b eyond the bounds of market relations (for which it was initially developed) are pointed out. (C) 2000 Editions scientifiques et medicales Elsevier SAS .