Formula Of Power/Sample Size Calculation In Gwas

Question

[nnlnn]

Genetic Power Calculator

Just like the web-based tool in the above link does, we provide some parameters then we get power and sample size estimates under different genetic models. But I want to know the formula behind these calculations. I searched for literature but got no really helpful paper/tutorial. Could you point me to some references? Thank you very much.

[Andrew Su]

Elsewhere on that same website (http://pngu.mgh.harvard.edu/~purcell/gpc/), there is a link to this publication (http://bioinformatics.oxfordjournals.org/content/19/1/149.full.pdf+html). Perhaps that is a good starting point?

Answer 1

[Neilfws]

"Genetic power" is really just an implementation of the more general concept of statistical power. I'd start with the Wikipedia entry, then a Google search for "statistical power" + gwas should return lots of relevant hits. For example:

Designing Genome-Wide Association Studies: Sample Size, Power, Imputation, and the Choice of Genotyping Chip

[nnlnn]

Thanks. I found this paper "Case-Control Studies of Genetic Markers: Power and Sample Size Approximations for Armitage’s Test for Trend", which seemingly is what I want.