In response to my earlier reply about graphing comparitive baseline hazards
(one frailty, one non-frailty), Eldira <[email protected]> now asks:
> Many thanks for your help. It works well now but I have another question.
> You add the option alpha1 when predictiong the hazard after running the
> model with heterogeneity- predict h_frailty, hazard alpha1. Does that mean
> that you assume shared frailty?
No, I do not assume shared frailty in the model. Using the -alpha1- option
when -predict-ing gives estimates of the conditional (or individual) predicted
quantity, in this case, the hazard. If you do fit a shared frailty model,
-alpha1- becomes the default to -predict-, but you do not have to assume
shared frailty to use -alpha1-.
> In my data, I have no reason to believe that there is shared frailty. Should
> I use alpha1, unconditional or no option at all?
It depends (see my earlier post). If you want to compare individual hazards
use -alpha1-. Use -unconditional- to compare population hazards.
--Bobby
[email protected]
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
