Fig. 1

Potential prior distributions for the APACHE-adjusted odds ratio: a Prior from the treatable cohort b 75% weighted (25% down-weighted) prior from the treatable cohort; c 50% down-weighted prior from the treatable cohort; d uninformative prior, ignoring external evidence on treatment efficacy, a distribution that is essentially flat over the range of plausible values. Each figure shows the corresponding 95% central credible interval (CrI) and the prior probability that the odds ratio for treatment with PMX is less than 1, along with this same probability expressed as odds in favor of there being a treatment effect (i.e., a 97.0% probability of benefit is the same as an odds of benefit of 97 to 3 or 32.3 to 1)