projpred Stan Logo

The R package projpred performs the projection predictive variable selection for various regression models. Usually, the reference model will be an rstanarm or brms fit, but custom reference models can also be used. Details on supported model types are given in section “Supported types of models” of the main vignette1.

For details on how to cite projpred, see the projpred citation info on CRAN2. Further references (including earlier work that projpred is based on) are given in section “Introduction” of the main vignette.

The vignettes3 illustrate how to use the projpred functions in conjunction. Details on the projpred functions as well as some shorter examples may be found in the documentation4.


There are two ways for installing projpred: from CRAN or from GitHub. The GitHub version might be more recent than the CRAN version, but the CRAN version might be more stable.



From GitHub

This requires the devtools package, so if necessary, the following code will also install devtools (from CRAN):

if (!requireNamespace("devtools", quietly = TRUE)) {
devtools::install_github("stan-dev/projpred", build_vignettes = TRUE)

To save time, you may omit build_vignettes = TRUE.

  1. The main vignette can be accessed offline by typing vignette(topic = "projpred", package = "projpred") or—more conveniently—browseVignettes("projpred") within R.

  2. The citation information can be accessed offline by typing print(citation("projpred"), bibtex = TRUE) within R.

  3. The overview of all vignettes can be accessed offline by typing browseVignettes("projpred") within R.

  4. The documentation can be accessed offline using ? or help() within R.