Lan-DeMets Method - Statistical Programs for Clinical Trials

Programs for Computing Group Sequential Boundaries Using the Lan-DeMets Method,
Version 2.1, Last Update: 11/17/03



Binaries and Source


FORTRAN programs for the computation of boundaries and exit probabilities
in the sequential analysis of clinical trials are described. The computations
are appropriate for any trial based on normally distributed test statistics
with independent increments, including those in which patients give a single
continuous or binary response, survival studies, and certain longitudinal
designs. Interim analyses need not be equally spaced, and their number
need not be specified in advance. In addition to boundaries, power computations,
probabilities associated with a given set of boundaries, and confidence
intervals can be computed. An explanation of the input and output, along
with some verbatim transcripts of interactive sessions are included. Some
theoretical background and description of the numerical computations is
provided in the documentation appendix. The program and this documentation
are updates of earlier versions.

  • Windows
  • *works on Windows 7 with java 1.7

    • Microsoft Windows graphical user interface for ld98.
      Download the ZIP file, create a new directory
      (e.g. WinLD) and unzip the contents into the new directory. Program name is winld.exe. Create a
      shortcut on your Windows Desktop for easy access.

  • Unix

  •      To compile: {gfortran -o ldbnds ldbnds.f}


David M. Reboussin

Department of Public Health

Bowman Gray School of Medicine

Winston-Salem, NC 27157

David L. DeMets

Department of Biostatistics and Medical Informatics, Department of Statistics

University of Wisconsin

Madison, WI 53706

KyungMann Kim

Department of Biostatistics and Medical Informatics, Department of Statistics

University of Wisconsin

Madison, WI 53706

K. K. Gordon Lan

Pfizer Central Research

Groton, CT 06340

Windows Compatibility Check your version of Windows and java before use. Tested and verified on Windows 7 SP1 64-bit and java 1.7u67 (32-bit). *The Landemets software is widely compatible with Windows - 98 through Windows 7. WinLD (Microsoft Windows graphical user interface for ld98) and ld98.exe work fine even in Windows 8.1 (although you have to tell it that you really do want to run the program even though Windows doesn't know if it's "safe"). The ldbnds.exe program, however, will not run in Windows 8.

Program for Computing Sample Size, Version 1.0, Last Update: 2/25/04




SampleSize was developed using Sun's Java2 programming language. It is being distributed as
a Java Archive File (JAR), which should execute on most MS Windows systems without any
additional software installation. Simply download the jar into a folder (e.g.
c:\SampleSize) and create a shortcut to it on your desktop. However, if it does not run you
will need to download the Java2 Runtime Environment from Sun's Java web site. A link to the
download area is provided in the "Program" area. Also, since this program is in Java, you can
run it on any system that has a Java Runtime Environment (v1.4.1 or higher). Visit Sun's
Java web site for more information.

If you need to include the output from this program in a word processor, it is recommended
that you "Print" to an Adobe PDF file and then use Acrobat to copy the table (using "Select
Table") or the graph (using "Select Image") and then paste either into your document.

  • Click Here to download the SampleSize program (v1.02)

  • Click Here to download the SampleSize program (v1.01)
  • The SampleSize Manual is no longer available
  • If SampleSize does not run,
    you may need a new version of Java.
    the Java2 Windows Runtime Environment v1.4.2. Select the "Windows Installation, Multi-language"
    download. After clicking the "Download" link for the JRE, a dialog box pops up -- choose the
    "Open" option. This will prompt you through the steps to download. (The letters "iftw" mean
    "install from the web".) If you wish to install the package offline, select the "Windows
    Offline Installation, Multi-language" download and save the file to disk. Install per

  • Download the Java2 Runtime
    Environment. Select the J2SE v1.4.2 or higher JRE. Install per

Friedman LM, Furberg CD, DeMets DL: Fundamentals of Clinical Trials, Third Edition,
New York, 1998, Springer-Verlag