Nobel Prize winner: Heckman (Self-selection Heckman (Heckman correction…
Nobel Prize winner: Heckman
James j. Heckman (1944-present)
Professor University of Chicago since 1973
Nobel Prize in 2000 :
"for his development of theory and methods for analyzing selective samples”
B.A. Colorado College (1951), Ph.D. Princeton (1971)
Empirical program evaluation, despite the fact that U of Chicago generally had a theoretical bias against government intervention
1. Effect Title VII of Civil rights act:
--> Prohibits discrimination based on race, color, religion, sex
and national origin.
“I truly did want to show that the government didn’t have an impact”, but the data showed “it had a huge effect”.
2. Review of The Bell Curve (Murray and Herrnstein):
Authors argued that
IQ was a good predictor for academic and economic success, as well as criminal activity
Whites had on average higher IQ than blacks, largely due to genetic differences (!)
Intelligence is product of nature and nurture, which are hard to distinguish empirically
Ability is unevenly distributed, but it is not primarily driven by genetics.
--> Perry Preschool evaluation: importance of investments in young children
Nobel Prize research
Applying econometric analysis in order to test econometric models.
Mostly known "for his development of theory and methods for analyzing selective samples”
--> Self-selection bias
Problematic: if characteristics are difficult to measure (unobserved data) E.g. Motivation, attitude, reliability, etc.
Random assignment experiments, though not always possible
Self-selection bias: if groups were different from the beginning
Heckman correction procedure:
Define the problem and ensure that researchers understand limitations of
Developed statistical techniques to correct for bias
(Earnings_CollegeGrad – Earnings_HighSchoolGrad) = return to college?