cp {PWEALL} | R Documentation |
Conditional power given observed log hazard ratio
Description
This will calculate the conditional power given the observed log hazard ratio based on Cox model
Usage
cp(Dplan=300,alpha=0.05,two.sided=1,pi1=0.5,Obsbeta=log(seq(1,0.6,by=-0.01)),
BetaD=log(0.8),Beta0=log(1),prop=seq(0.1,0.9,by=0.1))
Arguments
Dplan |
Planned number of events at study end |
alpha |
Type 1 error rate |
two.sided |
=1 two-sided test and =0 one-sided test |
pi1 |
Allocation probability for the treatment group |
Obsbeta |
observed log hazard ratio |
BetaD |
designed log hazard ratio, i.e. under alternative hypothesis |
Beta0 |
null log hazard ratio, i.e. under null hypothesis |
prop |
proportion of |
Details
This is to calculated conditional power at time point when certain percent of target number of event has been observed and an observed log hazard ratio is provided.
Value
CPT |
Conditional power under current trend |
CPN |
Conditional power under null hypothesis |
CPD |
Conditional power according to design, i.e. under alternative hypothesis |
Note
This will calculate the conditional power given the observed log hazard ratio based on Cox model
Author(s)
Xiaodong Luo
References
Halperin, Lan, Ware, Johnson and DeMets (1982). Controlled Clinical Trials.
See Also
Examples
###Calculate the CP at 10-90 percent of the target 300 events when the observed HR
###are seq(1,0.6,by=-0.01) with 2:1 allocation
###ratio between the treatment group and the control group
cp(pi1=2/3)