Older and Wiser? Birth Order and IQ of Young Men

Sandra Black, Paul Devereux and Kjell G Salvanes

No 3007, IZA Discussion Papers from Institute of Labor Economics (IZA)

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.

Keywords: birth order; IQ (search for similar items in EconPapers)
JEL-codes: I2 J1 (search for similar items in EconPapers)
Pages: 27 pages
Date: 2007-08
New Economics Papers: this item is included in nep-edu
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (23)

Published - published in: CESifo Economic Studies, 2011, 57 (1), 103-120

Downloads: (external link)
https://docs.iza.org/dp3007.pdf (application/pdf)

Related works:
Journal Article: Older and Wiser? Birth Order and IQ of Young Men (2011)
Working Paper: Older and Wiser? Birth Order and IQ of Young Men (2007)
Working Paper: Older and Wiser? Birth Order and IQ of Young Men (2007)
Working Paper: Older and wiser? Birth order and IQ of young men (2007)
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:iza:izadps:dp3007

Ordering information: This working paper can be ordered from
IZA, Margard Ody, P.O. Box 7240, D-53072 Bonn, Germany

Access Statistics for this paper

More papers in IZA Discussion Papers from Institute of Labor Economics (IZA) IZA, P.O. Box 7240, D-53072 Bonn, Germany. Contact information at EDIRC.
Bibliographic data for series maintained by Holger Hinte ().