COXREG <options>;
The COXREG statement performs power and sample size analyses for the score test of a single scalar predictor in Cox proportional hazards regression for survival data, possibly in the presence of one or more covariates that might be correlated with the tested predictor.
Table 89.2 summarizes the options available in the COXREG statement.
Table 89.2: COXREG Statement Options
Option 
Description 

Define analysis 

Specifies the statistical analysis 

Specify analysis information 

Specifies the significance level 

Specifies the number of sides and the direction of the statistical test 

Specify effects 

Specifies the value from the regression of the predictor of interest on the remaining predictors 

Specifies the hazard ratio 

Specify variability 

Specifies the standard deviation of the predictor variable being tested 

Specify sample size 

Specifies the probability that an uncensored event occurs 

Specifies the expected total number of events 

Enables fractional input and output for sample sizes 

Specifies the sample size 

Specify power 

Specifies the desired power of the test 

Control ordering in output 

Controls the output order of parameters 
Table 89.3 summarizes the valid result parameters for different analyses in the COXREG statement.
Table 89.3: Summary of Result Parameters in the COXREG Statement
To specify the sample size, choose one of the following parameterizations:
sample size (by using the NTOTAL= option) and event probability (by using the EVENTPROB= option)
number of events (by using the EVENTSTOTAL= option)
This section summarizes the syntax for the common analyses that are supported in the TWOSAMPLESURVIVAL statement.
You can use the NTOTAL= and EVENTPROB= options, as in the following statements. Default values for the SIDES= , ALPHA= , and TEST= options specify a twosided score test with a significance level of 0.05.
proc power; coxreg hazardratio = 1.4 rsquare = 0.15 stddev = 1.2 ntotal = 80 eventprob = 0.8 power = . ; run;
You can also use the EVENTSTOTAL= option, as in the following statements:
proc power; coxreg hazardratio = 1.6 rsquare = 0.2 stddev = 1.1 power = 0.9 eventstotal = . ; run;