We typically ask if an effect exists. But sometimes we want to ask if it does not. For example, how many of the “failed” replications in the recent reproducibility project published in Science (.pdf) suggest the absence of an effect? Data have noise, so we can never say ‘the effect is exactly zero.’ We can…

# Category: On Bayesian Stats

## [35] The Default Bayesian Test is Prejudiced Against Small Effects

When considering any statistical tool I think it is useful to answer the following two practical questions: 1. “Does it give reasonable answers in realistic circumstances?” 2. “Does it answer a question I am interested in?” In this post I explain why, for me, when it comes to the default Bayesian test that’s starting to…

## [13] Posterior-Hacking

Many believe that while p-hacking invalidates p-values, it does not invalidate Bayesian inference. Many are wrong. This blog post presents two examples from my new “Posterior-Hacking” (SSRN) paper showing selective reporting invalidates Bayesian inference as much as it invalidates p-values. Example 1. Chronological Rejuvenation experiment In “False-Positive Psychology” (SSRN), Joe, Leif and I run experiments to demonstrate how easy…