The third paragraph presents the definitions of earning function and of rate of return of investments in education. The Mincer's formulation is here rewritten:
[12] ln y b0 b1s b2x b3x2 u
where
ln y = logarithm of labor income13,
s = years of schooling,
x = years of experience calculated as x = t-s-6 (where t is the age).
In the [12], the rate of return of education is supposed to be constant for every level of schooling and experience and it is given by the coefficient of s, (b1).
This work estimates the [12] using individual data integrated with family information from
Canada, US (1994) and Italy (1995), kindly provided by the Luxembourg Income Study (LIS)14 and acquired from national official survey sources15.