Report

Small Family, Smart Family? Family Size and the IQ Scores of Young Men

Author(s) / Creator(s)

Black, Sandra E.
Devereux, Paul J.
Salvanes, Kjell G.

Abstract / Description

How do families influence the ability of children? Cognitive skills have been shown to be a strong predictor of educational attainment and future labor market success; as a result, understanding the determinants of cognitive skills can lead to a better understanding of children's long run outcomes. This paper uses a large dataset on the male population of Norway and focuses on one family characteristic: the effect of family size on IQ. Because of the endogeneity of family size, we instrument for family size using twin births and sex composition. IV estimates using sex composition as an instrument show no negative effect of family size; however, IV estimates using twins imply that family size has a negative effect on IQ. Our results suggest that effect of family size depends on the type of family size intervention. We conclude that there are no important negative effects of expected increases in family size on IQ but that unexpected shocks to family size resulting from twin births have negative effects on the IQ of existing children.

Keyword(s)

Familiengröße Kind Intelligenzquotient Familiengröße Kind Intelligenzquotient family size IQ

Persistent Identifier

Date of first publication

2007

Is part of series

Forschungsinstitut zur Zukunft der Arbeit/ Institute for the Study of Labor: IZA Discussion Paper Series;3011

Citation

  • Author(s) / Creator(s)
    Black, Sandra E.
  • Author(s) / Creator(s)
    Devereux, Paul J.
  • Author(s) / Creator(s)
    Salvanes, Kjell G.
  • PsychArchives acquisition timestamp
    2022-11-17T11:01:20Z
  • Made available on
    2008-06-03
  • Made available on
    2015-12-01T10:32:09Z
  • Made available on
    2022-11-17T11:01:20Z
  • Date of first publication
    2007
  • Abstract / Description
    How do families influence the ability of children? Cognitive skills have been shown to be a strong predictor of educational attainment and future labor market success; as a result, understanding the determinants of cognitive skills can lead to a better understanding of children's long run outcomes. This paper uses a large dataset on the male population of Norway and focuses on one family characteristic: the effect of family size on IQ. Because of the endogeneity of family size, we instrument for family size using twin births and sex composition. IV estimates using sex composition as an instrument show no negative effect of family size; however, IV estimates using twins imply that family size has a negative effect on IQ. Our results suggest that effect of family size depends on the type of family size intervention. We conclude that there are no important negative effects of expected increases in family size on IQ but that unexpected shocks to family size resulting from twin births have negative effects on the IQ of existing children.
    en
  • Persistent Identifier
    https://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:291-psydok-16286
  • Persistent Identifier
    https://hdl.handle.net/20.500.11780/1087
  • Persistent Identifier
    https://doi.org/10.23668/psycharchives.8871
  • Language of content
    eng
  • Is part of
    IZA Discussion Paper Series No. 3011
  • Is part of series
    Forschungsinstitut zur Zukunft der Arbeit/ Institute for the Study of Labor: IZA Discussion Paper Series;3011
  • Keyword(s)
    Familiengröße
    de
  • Keyword(s)
    Kind
    de
  • Keyword(s)
    Intelligenzquotient
    de
  • Keyword(s)
    Familiengröße
    de
  • Keyword(s)
    Kind
    de
  • Keyword(s)
    Intelligenzquotient
    de
  • Keyword(s)
    family size
    en
  • Keyword(s)
    IQ
    en
  • Dewey Decimal Classification number(s)
    150
  • Title
    Small Family, Smart Family? Family Size and the IQ Scores of Young Men
    de
  • DRO type
    report
  • Visible tag(s)
    PsyDok