[R] logrank test

[Terry Therneau]

 The information below is not nearly enough information to work from.  We need 
to know what the data look like!  This could be a feature of the statistical 
test, the code, or the particular data set you have in hand.
 	Terry Therneau
 	
--begin included message ---

hie carried out a comparison of survival curves using the log rank test in R 
with the values of rho ranging from -2 to 2 in  increments of 0.5 the question 
is at rho=-1.5 the power of the test seems to fluctuate or differ from the trend 
shown by the other values of rho is the statistical reason for this 
difference.ie if the power is increasing as i move from 0 to -2 at rho=-1.5 the 
power either greatly increases/decreases then at rho = -2 it follows the general 
trend 

if any one can help then thanks although this might not be an R question.