A software package for fitting and comparing failure-time models within the R software environment ( This tool empowers users to perform the model fitting, ranking, and testing procedures described in Skalski and Whitlock (2020). Included in this software are: (1) routines for fitting non-parametric Kaplan-Meier survival estimates from the generalized F distribution and Vitality families of parametric failure time models; (2) specialized plotting tools; (3) methods for ranking alternative models using a goodness-of-fit metric; (4) and more. Main dependencies include the R packages: flexsurv, survival, and vitality.

Source code for this software is publicly accessible on GitHub. The package carries Version 3 GNU General Public License (GPLv3), which guarantees openness of derivative works and forbids proprietization.

Guidance on use of CBR software is provided in the reference manual and user's manual. Individual assistance can be requested by emailing — we are happy to answer questions on our software.

Current Version