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| From | Steven Samuels <sjsamuels@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: Question about Baseline Hazard in Parametric Hazard Models |
| Date | Mon, 8 Nov 2010 20:23:43 -0500 |
---Two suggestions: 1) -stpm2- from SSC, which uses restricted cubic splines; and 2) -stcox-, followed by -stcurve-, which will smooth the Cox baseline hazard. I recommend against third degree polynomials, because they can curve up or down at the ends unpredictably and implausibly.
Steve Steven J. Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA Voice: 845-246-0774 Fax: 206-202-4783 On Nov 8, 2010, at 5:33 PM, Irwin T.S. Wang wrote: Dear All, I would like to specify/estimate a baseline hazard function, which is not among the distribution provided by Stata, e.g. exponential, Gompertz, in a Proportional Hazard (PH) models. For example, I want to restrict the shape of the the baseline hazard to a third degree polynomial in time, such that Lamda0(t) = exp[a0 + b1*(t) + b2*(t^2) + b3*(t^3)] Can I do that in Stata? Thank you very much in advance. Any info will be greatly appreciated. T.S. Wang * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/