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The Effects of Closely Spaced and Widely Spaced Sibship on Intellectual Development


Guo, Guang & VanWey, Leah K. (1999). The Effects of Closely Spaced and Widely Spaced Sibship on Intellectual Development. American Sociological Review, 64(2), 199-206.


For too long, cross-sectional studies have been the basis for causal arguments concerning the effect of sibship size on intellectual development. What if the sibship size effects obtained from cross-sectional studies are wrong? If they are, the policy implications would be obvious and ominous, as one of our original paper's reviewers commented. Motivated by this concern, we have reexamined the sibship-size effects using longitudinal data and methods (Guo and VanWey 1999, henceforward G&V). The goal of this longitudinal approach is to control for potentially important confounding influences shared among siblings and among repeated measures of the same individuals. Keeping this goal in mind, we turn now to the issues raised by Phillips (1999) and Downey et al. (1999). Considering that we agree with most of Phillips' comments, we direct our reply mainly to the critique by Downey, Powell, Steelman, and Pribesh (henceforward DPS&P). In order to respond to each of DPS&P's main critiques directly and specifically, we divide our reply into five sections with each corresponding to a section in DPS&P's comment. We have kept DPS&P's original subtitles to help the reader follow the debate.


Reference Type

Journal Article

Year Published


Journal Title

American Sociological Review


Guo, Guang
VanWey, Leah K.