The systematic analysis on wages data for individuals and enterprises, more and more frequent in the studies of empirical labour economy, shows invariably this finding: there are important wage differences (and, in a more general sense, differences of labour cThe systematic analysis on wages data for individuals and enterprises, more and more frequent in the studies of empirical labour economy, shows invariably this finding: there are important wage differences (and, in a more general sense, differences of labour cost) which may not be explained through the competitive model of labour market functioning. This article makes a
brief review of the forecasts of the competitive modelo It al so examines the main non-competitive advanced reasons for the existence of cost differentials (wages negociation models and efficiency wages theory), describes the evidence obtained -in a recent research- on the presence and magnitude of these differentials in the Spanish manufacture to finally compare it with the evidence obtained in other researches.[+][-]