The first massive replication project in psychology has just reached completion (several others are to follow). A large group of researchers, which I will refer to as ManyLabs, has attempted to replicate 15 findings from the psychological literature in various labs across the world. The paper is posted on the Open Science Framework (along with the data) and Ed Yong has authored a very accessible write-up . [ Update May 20, 2014, the article is out now and is open access.] What can we learn from the ManyLabs project? The results here show the effect sizes for the replication efforts (in green and grey) as well as the original studies (in blue). The 99% confidence intervals are for the meta-analysis of the effect size (the green dots); the studies are ordered by effect size. Let’s first consider what we canNOT learn from these data. Of the 13 replication attempts (when the first four are taken together), 11 succeeded and 2 did not (in fact, at some point ManyLabs su...