Analyses of the literature also showed that low power increases the proportion of false-positive to true-positive findings among those studies that achieve nominal statistical significance (Munafo and Flint, 2010). Finally, genetic association studies published in journals with a high impact factor tend to be based on smaller sample sizes while reporting larger effect sizes and are therefore more likely to provide an overestimate of the true effect size (Munafo et al., 2009). In light of evidence for high rates of reports containing false positive findings, a number of journals in the field of psychiatric and behavior genetics have adopted more restrictive editorial policies for the acceptance of studies reporting candidate gene association findings.
