Replication and Researchers' Understanding of Confidence Intervals and Standard Error Bars.

Confidence intervals (CIs) and standard error bars give information about replication, but do researchers have an accurate appreciation of that information? Authors of journal articles in psychology, behavioral neuroscience, and medicine were invited by email to visit a Web site and indicate on a figure where they judged replication means would plausibly fall. Responses from 263 researchers suggest that many leading researchers in the 3 disciplines underestimate the extent to which future replications will vary. A 95% CI will on average capture 83.4% of future replication means. A majority of respondents, however, held the confidence-level misconception that a 95% CI will on average capture 95% of replication means. Better understanding of CIs is needed if they are to be successfully used more widely in psychology.