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Titolo:
A note on the statistical power in extended twin designs
Autore:
Posthuma, D; Boomsma, DI;
Indirizzi:
Free Univ Amsterdam, Dept Biol Psychol, NL-1081 HV Amsterdam, Netherlands Free Univ Amsterdam Amsterdam Netherlands NL-1081 HV terdam, Netherlands
Titolo Testata:
BEHAVIOR GENETICS
fascicolo: 2, volume: 30, anno: 2000,
pagine: 147 - 158
SICI:
0001-8244(200003)30:2<147:ANOTSP>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
QUANTITATIVE TRAITS; ALCOHOLISM;
Keywords:
sample size; heritability; methodology; sibship size; twin study;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Social & Behavioral Sciences
Life Sciences
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Posthuma, D Free Univ Amsterdam, Dept Biol Psychol, De Boelelaan 1111, NL-1081 HV Amsterdam, Netherlands Free Univ Amsterdam De Boelelaan 1111 Amsterdam Netherlands NL-1081 HV
Citazione:
D. Posthuma e D.I. Boomsma, "A note on the statistical power in extended twin designs", BEHAV GENET, 30(2), 2000, pp. 147-158

Abstract

The power to detect sources of genetic and environmental variance varies with sample size, study design, effect size and the statistical significancelevel 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 didnot 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 additivegenetic, 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 onlya 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 generic influences, and common environment.

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Documento generato il 22/01/20 alle ore 22:38:25