Cunha, Flavio; Heckman, James J. - Forschungsinstitut zur Zukunft der Arbeit <Bonn> - 2007
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E-mail: jjh … conditioning variables X, we write:
Y0,t = Xβ0,t +U0,t (1)
Y1,t = Xβ1,t +U1,t, t = 1,...,T. (2)
The error terms Us,t are assumed to … satisfy E (Us,t | X) = 0, s = 0,1.2 Allowing for age-
specific returns incorporates post-school investment as a determinant of …