*! version 1.0 2 Jul 2018

Title

sampsi_gehan -- a command to give the parameters of the single stage Gehan design

Syntax

sampsi_gehan
[,
options]

Main
beta(#) specifies the first stage maximum probability of seeing no responses. Default value is 0.1.

p1(#) specifies the desired probability of response. Default value is 0.2.

se(#) specifies the desired standard error in the second stage. Default value is 0.1.

start(#) specifies the smallest n to start the search from. Default value is 1.

Description

sampsi_gehan calculates the sample sizes for the first and second stages of the Gehan design
(1961).

Options

Main

beta(#) specifies the first stage maximum probability of seeing no responses. Default value is 0.1

p1(#) specifies the desired probability of response. Default value is 0.2

se(#) specifies the desired standard error in the second stage. Default value is 0.1

start(#) specifies the smallest n to start the search from. Default value is 1

Examples

sampsi_gehan, p1(0.2) beta(0.05) se(0.1)

Stored results

Scalars

r(n1) The first stage sample size

r(p1) The interesting p1

Locals

r(beta) The type 2 error

r(se) Standard error

Matrices

r(n2) The second stage sample size

References

Gehan, E.A. (1961) The Determination of the Number of Patients Required in a Preliminary and
Follow-Up Trial of a New Chemotherapeutic Agent. Journal of Chronic Diseases, 13, 346-353.

Author

Dr Adrian Mander, MRC Biostatistics Unit, University of Cambridge.

Email adrian.mander@mrc-bsu.cam.ac.uk

See Also

Related commands:

sampsi_fleming (if installed) ssc install sampsi_fleming (to install this command)

simon2stage (if installed) ssc install simon2stage (to install this command)