The Reproducibility Project found that replication effects were on average in the same direction as the original studies, but were around half their magnitude. This points to an important bias in the scientific literature: a study which has found something ‘big’, at least some of which is likely to have been luck, is likely to lead to a prominent publication. In an analogy to regression to the mean, this might be termed ‘regression to the null’, where early exaggerated estimates of effects later decrease in magnitude towards the null hypothesis.
