Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-27T14:54:49.735Z Has data issue: false hasContentIssue false

Power of the Classical Twin Design Revisited: II Detection of Common Environmental Variance

Published online by Cambridge University Press:  21 February 2012

Peter M. Visscher*
Affiliation:
Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, Australia. [email protected]
Scott Gordon
Affiliation:
Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, Australia.
Michael C. Neale
Affiliation:
Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America.
*
*Address for correspondence: Peter M. Visscher, Genetic Epidemiology, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, QLD 4029, Australia.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We expand our previous deterministic power calculations by calculating the required sample size to detect C in ACE models. The theoretical expected value of the maximum log-likelihood for the AE model was derived using two optimisation methods and these gave near-identical results. Theoretical predictions were verified by computer simulation and the results agreed very well. We have developed a user-friendly web-based tool, TwinPower, to perform power calculations to detect either A or C for the classical twin design. This new tool can be found at http://genepi.qimr.edu.au/cgi-bin/twinpower.cgi

Type
Articles
Copyright
Copyright © Cambridge University Press 2008