Searching for the Archimedes' Lever:Is Quarter-of-Birth Really A Weak Instrumental Variable?

Using the 1% population sample survey data newly collected in 2005,this paper answers a theoretical question that attracts labor economists and micro-econometricians:is quarter-of-birth really a weak instrumental variable? In developed countries where very few individuals do not finish high school,the effect of quarter-of-birth on the variation of education is very small.Thus,the problem of quarter-of-birth being a weak instrument appears.However,in developing countries,more than half of the population do not enter high school.As a result,quarter-of-birth does significantly affect the variation in educational attainments and serves as a strong instrumental variable.