Computer programs for group sequential tests

We are making available for downloading some of the R code used to construct group sequential tests and to calculate their properties.

Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice appears in all copies.

These R routines in are released on an "as is" basis. There is no warranty. Users are warned that the developers are not liable for any errors or damages that occur as a result of using this code.

If you find these programs of help in your research we would ask that you acknowledge their source in reports and publications.

Programs presented here perform calculations to construct and evaluate group sequential tests. They are provided as a service to readers.

The programs are presented using the notation of the book and, in particular, the method of computation for normally distributed test statistics is as described in our Chapter 31.

Code is written in R. It is self-contained and does not rely on other software packages.

We would appreciate evidence of any errors or difficulties in using the programs -- but note we only claim to provide subroutines and program templates to help you in writing your own programs.

To retrieve .R files

Click on the highlighted name. A listing will appear in the window.
Click on File (top left hand corner) and select the Save option to save as an R file -- in text format. The program should be ready to use.

Here are some key routines. More documentation and examples of the use of these routines will follow ...

standards.R group sequential tests
erspt.R error spending tests
findroot.R finds the root of an increasing function
dunnett.R Dunnett P-value
simes.R Simes P-value

Example: Design for two treatment comparison with normally distributed responses

example1.R R script. You will need to substitute the appropriate path to upload files of routines standards.R, esptest.R and findroot.R
example1.pdf Output

Example: Design for two treatment comparison with survival endpoint

example2.R R script. You will need to substitute the appropriate path to upload files of routines standards.R, esptest.R and findroot.R
example2.pdf Output