Logic regression is now a package for R, a freely available statistical software, and Splus, a commercial software, distributed by Insightful . The core of the logic regression code has been translated into Fortran77, which is called from the R or Splus command line. The logic regression package can be downloaded here . It can be used to fit one logic regression model, it can be used to fit logic regression models of prespecified sizes, to carry out cross-validation, and to do various randomization tests. See the documentation (in particular the article from JCGS) for more information.

The help files for the packages can be downloaded here . The format of the output on your screen (if you choose to do so) is described in the helpfile of the function logreg() . The format of stored trees is explained here using gifs, and in the helpfile of the function logregtree() (using ascii characters only). Currently the Logic Regression methodology has scoring functions for linear regression (residual sum of squares), logistic regression (deviance), classification (misclassification), and proportional hazards models (partial likelihood). A feature of the Logic Regression methodology is that it is easily possible to extend the method to write ones own scoring function if you have a different scoring function. We describe here how to do that.