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Author: Wanstrom, Linda
Resulting in 3 citations.
1. Ang, Siew Ching
Rodgers, Joseph Lee
Wänström, Linda
The Flynn Effect Within Subgroups in the U.S.: Gender, Race, Income, Education, and Urbanization Differences in the NLSY-Children Data
Intelligence 38,4 (July-August 2010): 367-384.
Also: http://www.sciencedirect.com/science/article/pii/S0160289610000504
Cohort(s): Children of the NLSY79
Publisher: Elsevier
Keyword(s): Digit Span (also see Memory for Digit Span - WISC); Ethnic Studies; Flynn Effect; Gender; Household Income; I.Q.; Mothers, Education; Peabody Individual Achievement Test (PIAT- Math); Peabody Individual Achievement Test (PIAT- Reading); Racial Studies; Urbanization/Urban Living

Although the Flynn Effect has been studied widely across cultural, geographic, and intellectual domains, and many explanatory theories have been proposed, little past research attention has been paid to subgroup differences. Rodgers and Wanstrom (2007) identified an aggregate-level Flynn Effect (FE) at each age between 5 and 13 in the Children of the National Longitudinal Survey of Youth (NLSYC) PIAT-Math data. FE patterns were not obtained for Reading Recognition, Reading Comprehension, or Digit Span, consistent with past FE research suggesting a closer relationship to fluid intelligence measures of problem solving and analytic reasoning than to crystallized measures of verbal comprehension and memory. These prior findings suggest that the NLSYC data can be used as a natural laboratory to study more subtle FE patterns within various demographic subgroups. We test for subgroup Flynn Effect differences by gender, race/ethnicity, maternal education, household income, and urbanization. No subgroups differences emerged for three demographic categories. However, children with more educated (especially college educated) mothers and/or children born into higher income households had an accelerated Flynn Effect in their PIAT-M scores compared to cohort peers with lower educated mothers or lower income households. We interpret both the positive and the null findings in relation to previous theoretical explanations. [Copyright Elsevier]
Bibliography Citation
Ang, Siew Ching, Joseph Lee Rodgers and Linda Wänström. "The Flynn Effect Within Subgroups in the U.S.: Gender, Race, Income, Education, and Urbanization Differences in the NLSY-Children Data." Intelligence 38,4 (July-August 2010): 367-384.
2. Ghilagaber, Gebrenegus
Wänström, Linda
Adjusting for Selection Bias in Assessing the Relationship between Sibship Size and Cognitive Performance
Journal of the Royal Statistical Society: Series A (Statistics in Society) 178,4 (October 2015): 925-944.
Also: http://onlinelibrary.wiley.com/doi/10.1111/rssa.12098/abstract
Cohort(s): Children of the NLSY79, NLSY79
Publisher: Wiley Online
Keyword(s): Age at First Birth; Armed Forces Qualifications Test (AFQT); Cognitive Development; Family Size; Modeling, Multilevel; Mothers, Education; Peabody Individual Achievement Test (PIAT- Math); Sample Selection; Selectivity Bias/Selection Bias; Siblings

Permission to reprint the abstract has not been received from the publisher.

Consistent negative correlations between sibship size and cognitive performance (as measured by intelligence quotient and other mental aptitude tests) have been observed in past empirical studies. However, parental decisions on family size may correlate with variables affecting child cognitive performance. The aim of this study is to demonstrate how selection bias in studies of sibship size effects can be adjusted for. We extend existing knowledge in two aspects: as factors affecting decisions to increase family size may vary across the number and composition of current family size, we propose a sequential probit model (as opposed to binary or ordered models) for the propensity to increase family size; to disentangle selection and causality we propose multilevel multiprocess modelling where a continuous model for performance is estimated jointly with a sequential probit model for family size decisions. This allows us to estimate and adjust for the correlation between unmeasured heterogeneity affecting both family size decisions and child cognitive performance. The issues are illustrated through analyses of scores on Peabody individual achievement tests among children of the US National Longitudinal Survey of Youth 1979. We find substantial between-family heterogeneity in the propensity to increase family size. Ignoring such selection led to overestimation of the negative effects of sibship size on cognitive performance for families with 1-3 children, when known sources of selection were accounted for. However, the multiprocess modelling proposed could efficiently identify and control for such bias due to adverse selection.
Bibliography Citation
Ghilagaber, Gebrenegus and Linda Wänström. "Adjusting for Selection Bias in Assessing the Relationship between Sibship Size and Cognitive Performance." Journal of the Royal Statistical Society: Series A (Statistics in Society) 178,4 (October 2015): 925-944.
3. Rodgers, Joseph Lee
Wanstrom, Linda
Identification of a Flynn Effect in the NLSY: Moving from the Center to the Boundaries
Intelligence 35,2 (March-April 2007): 187-196.
Also: http://www.sciencedirect.com/science/article/pii/S0160289606000717
Cohort(s): Children of the NLSY79
Publisher: Elsevier
Keyword(s): Digit Span (also see Memory for Digit Span - WISC); Flynn Effect; I.Q.; Intelligence; Peabody Individual Achievement Test (PIAT- Math); Peabody Individual Achievement Test (PIAT- Reading); Peabody Picture Vocabulary Test (PPVT)

The Flynn Effect [Flynn, J.R. (1984). The mean IQ of Americans: Massive gains 1932 to 1978. Psychological Bulletin 95, 29-51.] is an increase in IQ of around .33 points per year, observed in developed (and some developing) countries during the past century. It emerges from problem solving and other non-verbal components of IQ. The cause has been argued and theories proposed. Rodgers [Rodgers, J.L. (1998). A critique of the Flynn Effect: Massive IQ gains, methodological artifacts, or both? Intelligence 26, 337-356.] noted that the search for causes has preceded specification of the nature of the effect. Our study uses a national sample of U.S. children to test for the Flynn Effect in PIAT-Math, PIAT-Reading Recognition, PIAT-Reading Comprehension, Digit Span, and PPVT. An effect of the predicted magnitude was observed for PIAT-Math when maternal IQ was controlled. This finding in a large representative sample with thousands of variables supports more careful evaluation of the Flynn Effect, in demographic, geographic, environmental, and biological domains. © 2006 Elsevier Inc. All rights reserved.
Bibliography Citation
Rodgers, Joseph Lee and Linda Wanstrom. "Identification of a Flynn Effect in the NLSY: Moving from the Center to the Boundaries ." Intelligence 35,2 (March-April 2007): 187-196.