The Misconception The relative belief ratio (e.g., Evans 2015, Horwich ^{1982}⁄_{2016}) equals the marginal likelihood. The Correction The relative belief ratio is proportional to the marginal likelihood. Dividing two marginal likelihoods (i.e., computing a Bayes factor) cancels the constant of proportionality, such that the Bayes factor equals the ratio of two complementary relative belief ratios …