Older and wiser? Birth order and IQ of young men

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Title: Older and wiser? Birth order and IQ of young men
Authors: Devereux, Paul J.
Black, Sandra E.
Salvanes, Kjell G.
Permanent link: http://hdl.handle.net/10197/740
Date: Aug-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.
Funding Details: National Science Foundation; California Center for Population Research (CCPR); The Research Council of Norway
Type of material: Working Paper
Publisher: Institute for the Study of Labor
Series/Report no.: IZA Discussion Paper Series; No. 3007
Copyright (published version): The Institute for the Study of Labor (IZA) 2007
Keywords: Birth orderIQ
Subject LCSH: Young men--Intelligence levels
Birth order--Norway
Intelligence levels--Norway
Other versions: http://ftp.iza.org/dp3007.pdf
Language: en
Status of Item: Not peer reviewed
Appears in Collections:Economics Research Collection

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