Group Sequential Design

Derives group sequential designs and describes their properties.


3.0-1, January, 2016

  • More changes to comply with R standards (in NAMESPACE - importFrom statements - and DESCRIPTION - adding plyr to imports) ensuring appropriate references.
  • Deleted link in documentation that no longer exists (gsBinomialExact.Rd).

3.0-0, December, 2015

  • Updated xtable extension to meet R standards for extensions.
  • Fixed xtable.gsSurv and print.gsSurv to work with 1-sided designs
  • Update to calls to ggplot to replace show_guide (deprecated) with show.legend arguments where used in geom_text (function from ggplot2 package) calls; no user impact
  • Minor typo fixed in sfLogistic help file
  • Cleaned up "imports" and "depends" in an effort to be an R "good citizen"
  • Registered S3 methods in NAMESPACE


  • Minor edit to package description to comply with R standards

2.9-3, November, 2014

  • Added sfTrimmed as likely preferred spending function approach to skipping early or all interim efficacy analyses; this also can adjust bound when final analysis is performed with less than maximum planned information. Updated help(sfTrimmed) to demonstrate these capabilities.
  • Added sfGapped, which is primarily intended to eliminate futility analyses later in a study; see help(sfGapped) for an example
  • Added summary.spendfn to provide textual summary of spending functions; this simplified the print function for gsDesign objects
  • Added sfStep which can be used to set an interim spend when the exact amount of information is unknown; an example of how this can be misused is provided in the help file.
  • Fixed rounding so that gsBoundSummary, xtable.gsSurv and summary.gsDesign are consistent for gsSurv objects

Reference manual

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3.0-1 by Keaven Anderson, 4 years ago

Browse source code at

Authors: Keaven Anderson

Documentation:   PDF Manual  

Task views: Clinical Trial Design, Monitoring, and Analysis, Design of Experiments (DoE) & Analysis of Experimental Data

GPL (>= 2) license

Imports plyr, methods

Depends on xtable, ggplot2

Suggests knitr, scales

Depended on by coprimary, gsbDesign.

Suggested by ADCT, gscounts, ph2bye, ph2mult.

See at CRAN