This problem is further exacerbated by the well-known publication bias towards reporting positive findings. Recent meta-analytic studies have demonstrated that this ubiquitous problem is especially pervasive in genetic research of complex neuropsychiatric and behavioral phenotypes. The existence of this bias is indicated by a higher rate of positive results among novel findings compared to replication attempts, since journals are more likely to accept a paper reporting a novel genetic association than a paper reporting a negative finding (Duncan and Keller, 2011; Flint and Munafo, 2012). Smaller studies are more likely to be published if they yield positive results because researchers are typically more reluctant to publish negative results, moreover, if a study reporting a negative result is underpowered, it is less likely to be accepted for publication than a similarly underpowered study reporting a positive finding.
