Exact tests of goodness of fit of log-linear models for rates

We propose Metropolis-Hastings sampling methods for estimating the exact co nditional p-value for tests of goodness of fit of log-linear models for mor tality rates and standardized mortality ratios. We focus on two-way tables, where the required conditional distribution is a multivariate noncentral h ypergeometric distribution with known noncentrality parameter. Two examples are presented: a 2 x 3 table, where the exact results, obtained by enumera tion, are available for comparison, and a 9 x 7 table, where Monte Carlo me thods provide the only feasible approach for exact inference.