caa a22 4500 475800001 CHVBK 20180406123734.0 cr unu---uuuuu 170329e20000301xx s 000 0 eng 10.1023/A:1001959306025 doi (NATIONALLICENCE)springer-10.1023/A:1001959306025 A Note on the Statistical Power in Extended Twin Designs [Elektronische Daten] [Daniëlle Posthuma, Dorret Boomsma] The power to detect sources of genetic and environmental variance varies with sample size, study design, effect size and the statistical significance level chosen. We explored whether the power of the classical twin study may be increased by adding non-twin siblings to the classical twin design. Sample sizes to detect genetic and shared environmental variation were compared for kinships with only twins, kinships consisting of twins and one additional sibling, and kinships with twins and two additional siblings. The effect of adding siblings to the classical twin design was considered for univariate and bivariate analyses. For the univariate case, adding one non-twin sibling resulted in a decrease in sample size needed to detect additive genetic influences in the presence of environmental influences. However, adding two additional siblings did not decrease the number of subjects as compared to the classical twin design. The sample size required to detect common environmental factors was also greatly decreased by adding one non-twin sibling. Adding two non-twin siblings resulted in a small additional decrease. In models including additive genetic, dominant genetic, and unique environmental effects, adding one sibling to a twin family decreased the required sample size to detect dominant genetic influences. Adding two siblings to a twin family resulted in only a slight additional decrease in sample size. In the bivariate case a similar pattern of results was found, in addition to the observation that the overall required sample size, as expected, was lower than in the univariate case. The decrease in sample size from bivariate testing was more pronounced in a design with one or two additional siblings, as compared to a design with twins only. It is concluded that a well considered choice of family design, i.e. including families with twins and one or two additional siblings increases the statistical power to detect sources of variance due to additive and non-additive genetic influences, and common environment. Plenum Publishing Corporation, 2000 Sample size nationallicence heritability nationallicence methodology nationallicence sibship size nationallicence twin study nationallicence Posthuma Daniëlle Department of Biological Psychology, Vrije Universiteit Amsterdam, Netherlands aut Boomsma Dorret Department of Biological Psychology, Vrije Universiteit Amsterdam, Netherlands aut Behavior Genetics Kluwer Academic Publishers-Plenum Publishers 30/2(2000-03-01), 147-158 0001-8244 30:2<147 2000 30 10519 https://doi.org/10.1023/A:1001959306025 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1001959306025 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Posthuma Daniëlle Department of Biological Psychology, Vrije Universiteit Amsterdam, Netherlands aut NATIONALLICENCE 700 1- Boomsma Dorret Department of Biological Psychology, Vrije Universiteit Amsterdam, Netherlands aut NATIONALLICENCE 773 0- Behavior Genetics Kluwer Academic Publishers-Plenum Publishers 30/2(2000-03-01), 147-158 0001-8244 30:2<147 2000 30 10519 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer