NCPA - National Center for Policy Analysis

SIBLING RIVALRY

October 24, 2005

Does the socioeconomic status of siblings diverge or converge across the life course? Do siblings from demographic groups that putatively differ on the degree of opportunity they enjoy vary with respect to how similar they turn out? According to new research by the National Bureau of Economic Research (NBER), sibling incomes tend to converge over the course their lifetimes.

In their study, NBER researchers discovered three new findings:

  • Sibling resemblance in occupational prestige is explained almost entirely by shared education, and sibling resemblance in family income is explained almost entirely by the combination of shared education, occupational prestige and earnings.
  • Across the life course, siblings converge in earnings and income and maintain stable correlations in education, occupational prestige, and wealth.
  • Black siblings have significantly lower correlations on earnings and income than non-black overall, but black siblings dramatically converge in income across the life course -- in their 20s, black siblings have a .181 correlation in income and about age 40, they have a .826 correlation in income -- suggesting almost complete social reproduction in income by the fifth decade of life for African Americans.

Furthermore, even when factors relating to a shared background - similarities in education and occupational prestige - are taken in account, roughly 60 percent of the phenomenon is unexplained, and may be genetically based, says NBER.

Source: Dalton Conley and Rebecca Glauber, "Sibling Similarity and Difference in Socioeconomic Status: Life Course and Family Resource Effects," National Bureau of Economic Research, May 2005; based upon: Dalton Conley and Rebecca Glauber, "Sibling Similarity and Difference in Socioeconomic Status: Life Course and Family Resource Effects," Working Paper 11320, National Bureau of Economic Research, May 2005.

For abstract:

http://www.nber.org/papers/W11320

For study text:

http://papers.nber.org/papers/w11320.pdf

 

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