Older and Wiser? Birth Order and IQ of Young Men

26 Pages Posted: 9 Jul 2007 Last revised: 3 Sep 2010

See all articles by Sandra E. Black

Sandra E. Black

University of Texas at Austin - Center for Law, Business, and Economics; National Bureau of Economic Research (NBER); IZA Institute of Labor Economics; Norwegian School of Economics (NHH) - Department of Economics

Paul J. Devereux

University College Dublin - Department of Economics; IZA Institute of Labor Economics

Kjell G. Salvanes

Norwegian School of Economics (NHH) - Department of Economics; IZA Institute of Labor Economics

Multiple version iconThere are 3 versions of this paper

Date Written: July 2007

Abstract

While recent research finds strong evidence that birth order affects children's outcomes such as education and earnings, the evidence on the effects of birth order on IQ is decidedly mixed. This paper uses a large dataset on the population of Norway that allows us to precisely measure birth order effects on IQ using both cross-sectional and within-family methods. Importantly, irrespective of method, we find a strong and significant effect of birth order on IQ, and our results suggest that earlier born children have higher IQs. Our preferred estimates suggest differences between first-borns and second-borns of about one fifth of a standard deviation or approximately 3 IQ points. Despite these large average effects, birth order only explains about 3% of the within-family variance of IQ. When we control for birth endowments, the estimated birth order effects increase. Thus, our analysis suggests that birth order effects are not biologically determined. Also, there is no evidence that birth order effects occur because later-born children are more affected by family breakdown.

Suggested Citation

Black, Sandra E. and Devereux, Paul J. and Salvanes, Kjell G., Older and Wiser? Birth Order and IQ of Young Men (July 2007). NBER Working Paper No. w13237. Available at SSRN: https://ssrn.com/abstract=999032

Sandra E. Black (Contact Author)

University of Texas at Austin - Center for Law, Business, and Economics ( email )

Austin, TX
United States

National Bureau of Economic Research (NBER) ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

IZA Institute of Labor Economics

P.O. Box 7240
Bonn, D-53072
Germany

Norwegian School of Economics (NHH) - Department of Economics

Helleveien 30
N-5035 Bergen
Norway

Paul J. Devereux

University College Dublin - Department of Economics ( email )

Dublin 4, 4
Ireland

IZA Institute of Labor Economics

P.O. Box 7240
Bonn, D-53072
Germany

Kjell G. Salvanes

Norwegian School of Economics (NHH) - Department of Economics ( email )

Helleveien 30
N-5035 Bergen
Norway
+47 5 595 9315 (Phone)
+47 5 595 9543 (Fax)

IZA Institute of Labor Economics

P.O. Box 7240
Bonn, D-53072
Germany

Here is the Coronavirus
related research on SSRN

Paper statistics

Downloads
35
Abstract Views
967
PlumX Metrics