Over fifty years ago, Sterling [42] offered evidence that almost all published psychological studies reported positive results. This trend has been persistent and perhaps even increasing over time [43], and particularly in the United States [44]. Evidence suggests perceived bias against negative results in peer-review [45], and a desire for aesthetically pleasing positive effects [46] leads authors to be less likely to even attempt to publish negative studies [45]. Instead, many psychological scientists report taking advantage of selective reporting and flexibility in analysis to make their research results more publishable [47, 48]. Such practices may contribute to unusually elevated likelihoods of positive results that are just below the nominal .05 threshold for significance (p-hacking) [49, 50].
