bayesassurance: An R Package for Calculating Sample Size and Bayesian Assurance

In this paper, we present bayesassurance, an R package designed for computing Bayesian assurance criteria which can be used to determine sample size in Bayesian inference setting. The functions included in the R package offer a two-stage framework using design priors to specify the population from which the data will be collected and analysis priors to fit a Bayesian model. We also demonstrate that frequentist sample size calculations are exactly reproduced as special cases of evaluating Bayesian assurance functions using appropriately specified priors.