Purpose: The present study had two purposes: provide an illustration of use of the National Longitudinal Survey of Youth 1979 Children's (CNLSY; U.S. Department of Labor, 2009) database and use the database to seek convergent evidence regarding the magnitude and significance of genetic effects influencing low and typical performers on measures of language, reading, and mathematics.
Methods: A kinship algorithm that assigned a degree of genetic relatedness to all available pairings was applied to the 1994 wave of the CNLSY sample. Four cognitive achievement outcomes related to language, reading, and mathematics were analyzed across the general sample as well as for children selected below the lowest 20(th) percentile.
Results: The tests of receptive vocabulary, decoding, reading comprehension, and mathematics all suggested estimates of group heritability and full sample heritability of moderate effect sizes, and all estimates were statistically significant. Furthermore, all estimates were within confidence intervals of previously reported estimates from twin and adoption studies.
Conclusion: The present study provides additional support for significant genetic effects across low and wide ranges of specific achievement. Moreover, this study supports that genetic influences on reading, language, and mathematics are generalizable beyond twin and adoption studies.