“…Other studies regarding the wage effects of educational mismatch also highlight that, in a given job with a specific level of required education, over-(under-) educated workers earn more (less) than those who have just the required education for the job (Battu et al, 1999, Dolton and Vignoles, 2000, Duncan and Hoffman, 1981, Groot, 1996, Groot and Maassen van den Brink, 2000, Sicherman, 1991, van der Meer, 2006. Although part of this premium (penalty) may be explained by workers' unobserved heterogeneity (Bauer, 2002, Chevalier, 2003, Dolton and Silles, 2008, Frenette, 2004, Lamo and Messina, 2010, McGuinness, 2003, McGuinness and Sloane, 2011, current evidence on the basis of human capital theory thus suggests that over-(under-) education increases (reduces) workers' productivity. 2 Another strand of the literature examines the impact of educational mismatch on job satisfaction and other correlates of workers' productivity (such as absenteeism, shirking, turnover or training).…”