Investigating the replicability of the social and behavioural sciences

We attempted replications of 274 claims of positive results from 164 quantitative papers published from 2009 to 2018 in 54 journals in the social and behavioral sciences. Replications were high-powered on average to detect the original effect size (Median = 99.6%), used original materials when relevant and available, and were peer-reviewed in advance through a standardized internal protocol. Replications showed statistically significant results in the original pattern for 151 of 274 claims (55.1% [95% CI 49.2 - 60.9%]) and for 80.8 of 164 papers (49.3% [95% CI 43.8 - 54.7%]) weighed for replicating multiple claims per paper. We observed modest variation in replication rates across disciplines (42.5% to 63.1%) though some estimates had high uncertainty. For claims with Pearson’s r effect sizes, the median was 0.25 [95% CI 0.21 - 0.27] for original studies and 0.10 [95% CI 0.09 - 0.13] for replication studies, a 82.4% [95% CI 67.8 - 88.2%] reduction in shared variance. Thirteen methods for evaluating replication success provided estimates ranging from 28.6% to 74.8% (median = 49.3%). Some decline in effect size and significance is expected based on power to detect original effects and regression to the mean due to replicating only positive results. The conditions that promote or inhibit replicability are worthy of additional investigation.