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st: eqivalent to stkerhaz for discrete time survival analysis?


From   Hilde Karlsen <Hilde.Karlsen@hio.no>
To   statalist@hsphsun2.harvard.edu
Subject   st: eqivalent to stkerhaz for discrete time survival analysis?
Date   Mon, 16 Feb 2009 12:00:31 +0100

Dear statalisters,

I am performing a survival analysis of attrition from the nursing occupation (dependent variable is binary: 1 eq 'death/moved out'; 0 eq not moved out, and the time variable is discrete and ranges from 1-13 'years sice graduation').

I have read that I should estimate a baseline hazard to describe the form of the hazardfunction. However, I am not sure how to do this. I've found an ado which is called stkerhaz, but it seems this command should only be used after stcox, and I will probably be using the hshaz (model 2) or logit or cloglog. Is there a command which can help me estimate the baseline hazard and plot the hazardfunction, or do I have to calculate this myself? In the latter case, how do I do this?

Furthermore, I've been playing around a bit with hshaz, and the computations/convergence take a lot of time, particularly for model 2. I get messages from stata iteration log that the likelihood is very close to non-concave (or something in that direction). What is the best method to 'avoid' this long series of iterations?

Here is the syntax I wrote (please tell me if it is wrong) where :
male = man eq 1;
year1_4 = 1 to 4 years after graduation;
year5_8 = 5 to 8 years after graduation
(the omitted category is 9-13 years after graduation)
LPNR is the id-variable
movedout is the dependent variable (1= moved out, 0=not moved out)
Year is the time wariable, ranging from 1-13 years after graduation from the nursing study program


hshaz male year1_4 year5_8 male*year1_4 male*year5_8, id(LPNR) dead(movedout) seq(year)


Do you by the way know of a document which gives examples of estimation techniques and interpretation of estimates for the hshaz-command? (something similar to the chapter 7 from http://www.iser.essex.ac.uk/iser/teaching/module-ec968 ?)


Best wishes,
Hilde



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