The point estimates for regression should be the same although the CI's for the MCMC methods might be wider (more conservative if that is what you mean by "more accurate"). I
I was able to install Brian Caffo's archived 'exactLoglinTest' package for my MacOS system with R 4.6.1 after adding: CPPFLAGS += -I/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/include to my .R/Makevars file. That allows the compilation step to find PrtUtil.h from an earlier version of R since it has been folded into R 4.6.x rather than currently being exposed. The Notes that Caffo chose not to fix did not cause any errors, at least to my minimal testing with the package's examples. Best; David Winsemius, MD, MPH > On Aug 21, 2026, at 1:21 AM, iagogv via R-help <[email protected]> wrote: > > Hi all, > > Can an exact Poisson regression be computed with R, instead of using the > standard (glm) Poisson using maximum likelihood? > > I am working with a collegue in a project, and I'd like to reproduce his > method, if not his results. He uses Stata, particularly the expoisson > function (https://www.stata.com/help.cgi?expoisson) in order to compute > the exact Poisson regression, relevant for small samples. > > expoisson fits an exact Poisson regression model, which produces more > accurate inference in small samples than standard > maximum-likelihood-based Poisson regression > > I know about exact Poisson tests > (https://stat.ethz.ch/R-manual/R-devel/RHOME/library/stats/html/poisson.test.html), > > but it does not allow to include offset. > > So, is there some way to reproduce exact Poisson regression with R? > > Thanks! > > Best, > > -- > Iago > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide https://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide https://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
