Twins are more different than commonly believed, but made less different by compensating behaviors

Jin young Choi, Myoung-jae Lee

Research output: Contribution to journalArticle

Abstract

Twin studies are popular, because twins are believed to be the same/similar in genes and environmental exposures. It is well documented, however, that the firstborns are healthier at birth. We use the entire U.S. record of twin births during 1995–2000 to show that the survival duration parameters differ between twins depending on the birth order. We also find that wiser (i.e., older or educated) or married (i.e., resource-richer) mothers take more care of the weaker, which is a “compensating” behavior reducing the twin difference, as opposed to “reinforcing (the twin difference)” behavior. The systematic survival pattern difference and the mother's intervention against nature send cautions to twin studies that regard twins homogeneous to interpret their findings accordingly. Since the survival duration in our data is 97% right-censored in one year, we devise a quantile-based ‘fixed-effect’ semiparametric estimator that can handle heavy censoring, which is our methodological contribution.

Original languageEnglish
Pages (from-to)18-31
Number of pages14
JournalEconomics and Human Biology
Volume35
DOIs
Publication statusPublished - 2019 Dec 1

Fingerprint

twin studies
birth order
reproductive behavior
Twin Studies
Mothers
resources
Birth Certificates
Birth Order
Environmental Exposure
Parturition
Genes

Keywords

  • Birth-order effect
  • Compensating behavior
  • Heavy censoring
  • Quantiles
  • Twin study

ASJC Scopus subject areas

  • Health(social science)

Cite this

Twins are more different than commonly believed, but made less different by compensating behaviors. / Choi, Jin young; Lee, Myoung-jae.

In: Economics and Human Biology, Vol. 35, 01.12.2019, p. 18-31.

Research output: Contribution to journalArticle

@article{d6b47e00603a43989eef2605c83b8e82,
title = "Twins are more different than commonly believed, but made less different by compensating behaviors",
abstract = "Twin studies are popular, because twins are believed to be the same/similar in genes and environmental exposures. It is well documented, however, that the firstborns are healthier at birth. We use the entire U.S. record of twin births during 1995–2000 to show that the survival duration parameters differ between twins depending on the birth order. We also find that wiser (i.e., older or educated) or married (i.e., resource-richer) mothers take more care of the weaker, which is a “compensating” behavior reducing the twin difference, as opposed to “reinforcing (the twin difference)” behavior. The systematic survival pattern difference and the mother's intervention against nature send cautions to twin studies that regard twins homogeneous to interpret their findings accordingly. Since the survival duration in our data is 97{\%} right-censored in one year, we devise a quantile-based ‘fixed-effect’ semiparametric estimator that can handle heavy censoring, which is our methodological contribution.",
keywords = "Birth-order effect, Compensating behavior, Heavy censoring, Quantiles, Twin study",
author = "Choi, {Jin young} and Myoung-jae Lee",
year = "2019",
month = "12",
day = "1",
doi = "10.1016/j.ehb.2019.03.007",
language = "English",
volume = "35",
pages = "18--31",
journal = "Economics and Human Biology",
issn = "1570-677X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Twins are more different than commonly believed, but made less different by compensating behaviors

AU - Choi, Jin young

AU - Lee, Myoung-jae

PY - 2019/12/1

Y1 - 2019/12/1

N2 - Twin studies are popular, because twins are believed to be the same/similar in genes and environmental exposures. It is well documented, however, that the firstborns are healthier at birth. We use the entire U.S. record of twin births during 1995–2000 to show that the survival duration parameters differ between twins depending on the birth order. We also find that wiser (i.e., older or educated) or married (i.e., resource-richer) mothers take more care of the weaker, which is a “compensating” behavior reducing the twin difference, as opposed to “reinforcing (the twin difference)” behavior. The systematic survival pattern difference and the mother's intervention against nature send cautions to twin studies that regard twins homogeneous to interpret their findings accordingly. Since the survival duration in our data is 97% right-censored in one year, we devise a quantile-based ‘fixed-effect’ semiparametric estimator that can handle heavy censoring, which is our methodological contribution.

AB - Twin studies are popular, because twins are believed to be the same/similar in genes and environmental exposures. It is well documented, however, that the firstborns are healthier at birth. We use the entire U.S. record of twin births during 1995–2000 to show that the survival duration parameters differ between twins depending on the birth order. We also find that wiser (i.e., older or educated) or married (i.e., resource-richer) mothers take more care of the weaker, which is a “compensating” behavior reducing the twin difference, as opposed to “reinforcing (the twin difference)” behavior. The systematic survival pattern difference and the mother's intervention against nature send cautions to twin studies that regard twins homogeneous to interpret their findings accordingly. Since the survival duration in our data is 97% right-censored in one year, we devise a quantile-based ‘fixed-effect’ semiparametric estimator that can handle heavy censoring, which is our methodological contribution.

KW - Birth-order effect

KW - Compensating behavior

KW - Heavy censoring

KW - Quantiles

KW - Twin study

UR - http://www.scopus.com/inward/record.url?scp=85064680287&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064680287&partnerID=8YFLogxK

U2 - 10.1016/j.ehb.2019.03.007

DO - 10.1016/j.ehb.2019.03.007

M3 - Article

VL - 35

SP - 18

EP - 31

JO - Economics and Human Biology

JF - Economics and Human Biology

SN - 1570-677X

ER -