Estimating the reproducibility of psychological science

Reproducibility is a defining feature of science, but the extent to which it characterizes science is unknown. Following a structured protocol, we conducted 100 replications of studies published in three psychology journals. Replication effects (​M​ = .198, ​SD​ = .255) were half the magnitude of original effects (​M​ = .396, ​SD​ = .193) representing a substantial decline effect. Ninety-seven percent of original studies had significant results (​p​ < .05). Thirty-six percent of replications had significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 38% of effects were subjectively rated to have replicated the original result; and, if no bias in original results is assumed, 70% of the meta-analytic combinations were significant effects. Correlational tests suggest that replication success is better predicted by the strength of original evidence than by characteristics of the original and replication teams. In sum, a large portion of replications did not reproduce evidence supporting the original results despite using high-powered designs and original materials when available. The open dataset provides a basis for hypothesis generation on the causes of irreproducibility.