st: Re: Survival Analysis estat phtest with very large sample size--need help

[graupel75@gmail.com]

Hi Peter,

I suspect you find something useful in 'Applied Survival Analysis'
(Hosmer, Lemeshow and May, 2008); I just quickly looked through and
didn't see a specific ref, but it's pretty comprehensive.

You could also run a Possion after -stsplit- and see how different the
IRRs are from your HRs; this has a more restrictive constant hazard
assumption but if you have a large number of failure times it should
be OK.

http://biostat.mc.vanderbilt.edu/wiki/pub/Main/LisaKaltenbach/poissonregtalk.pdf

Another option is to use flex parametric models (from ssc -stpm2-)
which allow much more freedom to model tvcs; if the hazard ratios are
basically unchanged, then you can feel confident using Cox even with
PH violations.

cheers-
Andrew Lover

______________________________________________
Epidemiologist
Centre for Infectious Disease Epidemiology Research (CIDER)
Saw Swee Hock School of Public Health
National University of Singapore
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