Lundborg, Petter; Nilsson, Anton; Rooth, Dan-Olof - Institute for the Study of Labor (IZA) - 2011
A large number of studies in labor economics estimate the returns to schooling using data on monozygotic twins, under the assumption that educational attainment is random within twin pairs. This exogeneity assumption has been commonly questioned, however, but there is to date little evidence on...