Publication Bias and Editorial Statement on Negative Findings

In February 2015, the editors of eight health economics journals sent out an editorial statement which aims to reduce the incentives to engage in specification searching and reminds referees to accept studies that: "have potential scientific and publication merit regardless of whether such studies' empirical findings do or do not reject null hypotheses that may be specified." In this study, we collect z-statistics from two health economics journals and compare the distribution of tests before and after the editorial statement. Our results suggest that the editorial statement decreased the proportion of test statistics rejecting the null hypothesis and that incentives may be aligned to promote more transparent research.