I am using proc phreg to estimate hazard ratios, my model is as follows:
time*event(0) = week|avg education race;
random zipcode;
I would like to get the hazard ratio for 'week'. I was originally doing this by hand by summing the estimate from week and the interaction term, but assume there is a way to do this using estimate/contrast?
Thank you!
Try a HAZARDRATIO statement instead. Much simpler syntax.
youdont have week as a main factor in the model, just in the interaction? you'll need to use 'at' in the hazardratio statement @Reeza suggested, see here: https://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#statug_phreg_sect0...
When I use the hazardratio statement I cannot recreate what I get when I am summing the coefficients by hand. This is why I wasn't using it initially - is there a specification that needs to be made?
Example:
Estimate | Exp summed estimate | Hazard Ratio from SAS | |
average | 0.000196 | 0.999763628 | 0.995 |
week | -0.0002121 | ||
week*average | -0.0000243 |
are you doing it by hand or in a data step? it could be rounding error, calculate the hr in a data step as exp(estimate). Also did you use 'at' in the hazard ratio statement? if you just sum them up then it's at average=1?
99% of the time the error is with the hand calculation.
Do it with a data step so you can't get any typo's or rounding errors and post your code if it still doesn't match.
Are you ready for the spotlight? We're accepting content ideas for SAS Innovate 2025 to be held May 6-9 in Orlando, FL. The call is open until September 25. Read more here about why you should contribute and what is in it for you!
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.
Find more tutorials on the SAS Users YouTube channel.