Are degrees as "signals" about to be depreciated? Spence's model re-examined[Le diplôme, un "signal" en voie de dépréciation? Le modèle de Spence réexaminé]

The expansion of massive higher education is a difficult challenge for the economic system, which has to absorb the growing flow of graduates, according to the expectations of those most directly concerned (firms and students). In this context, the first aim of the paper is to get clear the notion of degrees "quantitative" depreciation, which is different from "qualitative" devaluation and broader than classical lowering of social class for the graduates. As the prevailing model of human capital cannot analyse degrees depreciation, a general and theoretical appraisal of this phenomen is then proposed through the use of Spence's theory of "signal" (1973): the foundations of skills signalling are therefore re-examined and lead to the definition of two "scenarios" of depreciation - "running" after degrees and "fleeing" from degress -. The end of the paper is devoted to the first indications of depreciation in the case of France and to an interpretation of the expansion of higher education, which is alternative of that generally prevailing.