We used one additional, independent approach to test for evidence consistent with publication bias among replication attempts, hypothesizing that negative replication attempts may be published more readily when reported with some other novel, positive cG×E finding. Consistent with this, 63% (17/27) of negative replication attempts were reported with novel, positive cG×E findings whereas only 20% (2/10) of positive replication attempts were published with novel, positive cG×E findings (Fisher's exact test, p=0.03). Moreover, it appears that much larger sample sizes are needed in order for negative replication attempts to be published: the median sample size of the 10 “pure negative” replication attempts (not published alongside another novel, positive cG×E finding) was 1,019, more than six times the size of the median sample size (N=154) of the 10 positive replication attempts (T=9, p=0.001; see Figure 2).
