. Author manuscript; available in PMC: 2012 Nov 1.

Published in final edited form as: Genet Epidemiol. 2011 Sep 15;35(7):581–591. doi: 10.1002/gepi.20603

Table 1. Optimal Weights in GWAS Meta-analysis without Covariates.

Phenotype

Optimal Weight w_k for k^th Study^a

Case-control Status^b

{(\frac{n_{k 0} n_{k 1}}{n_{k}} p_{k} q_{k})}^{1 / 2}

Quantitative Trait^c

{(\frac{n_{k}}{ϕ_{k}} p_{k} q_{k})}^{1 / 2}

Poisson Count Data^d

(n_kμ_kp_kq_k)^1/2

Censored Survival Data^e

(m_kp_kq_k)^1/2

^a)

w_k are optimal under effect size homogeneity across sites, and are given up to a proportionality factor determined by the constraint $\sum_{k} w_{k}^{2} = 1$ . p_k = 1-q_k is the SNP MAF and n_k is the number of subjects in study k.

^b)

n_kj is the number of cases (j=1) and controls (j=0).

^c)

ϕ_k is the trait variance.

^d)

μ_k is the null expected count

^e)

m_k is the number of failures.