Dance of the Bayes factors

You might have seen the ‘Dance of the p -values’ video by Geoff Cumming (if not, watch it here). Because p -values and the default Bayes factors (Rouder, Speckman, Sun, Morey, & Iverson, 2009) are both calculated directly from t -values and sample sizes, we might expect there is also a Dance of the Bayes factors. And indeed, there is. Bayes factors can vary widely over identical studies, just due to random variation.