Fondamenti teorici della rigidità' salariale nell'ambito dei “Non Market Clearing Models”

The paper analyses the labour market in a framework of New Keynesian Economics (NKE). The aim of the NKE is to provide micro foundations to the main result of the Keynesian model, that is the rigidity of prices and wages as well as the presence of non market clearing equilibria. In the first part it is shown how rigidity determines involuntary unemployment having distinct characteristics and policy implications weather it comes from price rigidity in the good market (keynesian unemployment) or from wage rigidity in the labour market (classical unemployment). In the second part two labour market models are developed: the insider-outsider model and the efficiency wage model. These tray to meet the objection that non market clearing equilibria do not derive from a rational behaviour of economic agents in the labour market. It can be demonstrated, on the contrary, that involuntary unemployment is consistent with the first postulate of the neoclassical model that is the identity between the real wage and labour marginal productivity (expressed in efficiency units), even if the second postulate, the identity between marginal utility of wage and the marginal disutility of leisure time, can be rejected.