## Online MetaGAP calculator

### Description

MetaGAP is a versatile tool for calculating the statistical power of a meta-analysis of GWAS results and of the polygenic-score *R*² in a hold-out sample. The tool allows the user to specify the genetic correlation between the studies in a meta-analysis as well as the genetic correlations between the hold-out sample and the meta-analysis studies.

This calculator, accounting for imperfect genetic correlations between studies, provides (i) the power of a meta-analysis of GWAS results from different studies, and (ii) the expected *R*² of polygenic-score for a hold-out sample with SNP-weights based on the meta-analysis SNP-effect estimates.

Details on the underlying model, assumptions, and derivations, can be found in the De Vlaming et al. (2017).

Notes: (i) *h*² denotes SNP-based heritability and *N* sample size, (ii) lists for *h*² and *N* need to be comma-separated, (iii) replacing a list by a single number enforces the same value across all studies in the meta-analysis.

### Calculator

**Please enter the following quantities and click on the SUBMIT button:**