mantelhaen.test() gives the exact conditional p-value (for independence) and confidence intervals (CIs)for the common odds ratio for a stratified 2x2 table. The epitools package by Tomas Aragon (available via CRAN) contains functions which use fisher.test() to calculate mid-p exact p-values and CIs for the CMLE odds ratio for a single 2x2 table. The mid-p p-value for independence for a stratified 2x2 table is easy to calculate using mantelhaen.test(), but can anyone suggest a method for calculation of mid-p CIs for the common odds ratio? A search in the usual places draws a blank (but I am sure someone will immediately prove me wrong on that point...). Thanks to Andy Dean (of Epi-Info fame), I have a copy of public domain Pascal code from 1991 by David Martin and Harland Austin which calculates mid-p CIs for the common odds ratio by finding polynomial roots. Before trying to replicate that code in R (or C), I was wondering if anyone could suggest a better or easier way?

Tim C


