[R] Log rank test power calculations

[Marc Schwartz]

Daniel Brewer wrote:
> Does anyone have any ideas how I could do a power calculation for a log
> rank test.  I would like to know what the suggested sample sizes would
> be to pick a difference when the control to active are in a ratio of 80%
> to 20%.
> 
> Thanks
> 
> Dan

See the cpower() and spower() functions in Frank Harrell's Hmisc package
on CRAN.

HTH,

Marc Schwartz