Informed vs default prior
Hi
I recently ran several analyses using the informed prior vs the default prior. I understand why the same analyses using the informed prior gives a bigger Bayes factor compared to the default, but I didn’t expect the effect sizes to all be smaller (and credible intervals narrower) when using the informed prior. Does anybody know why this might be?
Comments
Informed priors are more narrow/precise than default priors; this carries over to the posterior. Effect sizes may be smaller or larger with an informed prior depending on the situation, but what happens is that the observed effect size is pulled to the prior mean; when the prior is precise, this pull will be stronger than when the prior is imprecise.
E.J.