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Updated: May 5, 2026

Using Cholesky Decomposition to Explore Individual Differences in Longitudinal Relations between Reading Skills
Published on: September 17, 2019
Genetic and environmental etiologies of reading disability: A twin study
1Institute for Behavioral Genetics, University of Colorado, Campus Box 447, 80309, Boulder, CO.
Abstract:
Previous twin studies of reading disability employed a comparison of concordance rates in identical and fraternal twin pairs as a test for genetic etiology. Recently, a statistically more powerful multiple regression analysis of twin data has been formulated to assess the importance of genetic factors in the development of reading difficulties. Application of this analysis to twin data from the Colorado Reading Project yields definitive evidence for a genetic etiology. Results from this study suggest that approximately 40 percent of the deficit observed in the disabled readers is due to genetic factors, 35 percent is due to environmental influences shared by members of twin pairs, and about 25 percent is the result of environmental factors unique to the individual and/or error variance.
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