Figure 1

Power (at α = 5%) for the bi-allelic case for a representative scenario of a variant with modest effect (OR = 1.3) following distinct modes of action (A-B, dominant; C-D, multiplicative, E-F, recessive, and G-H, over-dominant) under moderate heterogeneity (τ² = 0.025). The sample size for each study was randomly sampled from a uniform distribution on the interval [500-1000] and split equally into cases and controls (i.e. case to control ratio = 1). Color lines depict power estimates under different models of analysis: green (dominant), blue (per-allele odds ratio), red (recessive) and black (generalized odds ratio). Results for the log-additive trend were omitted because the striking similarity with the results of the per-allele odds ratio. Results are based on 5,000 replications under a random-effects model (DerSimonian-Laird method). f, allelic frequency. Scenarios with alternative magnitudes of heterogeneity or use of a fixed-effects model yielded qualitatively identical results.