Re: [R] parametric proportional hazard regression

From: Valentin Dimitrov <vsdimitrov_at_yahoo.com>
Date: Sat 08 Jul 2006 - 10:45:57 EST

>
> Those are not proportional hazards families of
> distributions. That is, if
> the distribution is gaussian for one value of the
> hazard ratio parameters
> it will not be gaussian for any other value.
>
> You can get accelerated failure models with these
> distributions using
> survreg() in the survival package.
>
>
> -thomas

I do not need a accelerated failure model, but a proportional hazard model with a f0= weibull, exponential, loglogistic or lognormal baseline distribution. The hazard function is
lambda(t)=exp(Xi*beta)*lambda0(t),
where lambda0 is the baseline hazard
lambda0(t)=f0(t)/(1-F0(t)) where f0 and F0 are the baseline density and cumulative distribution functions.
This is a proportional hazard model since the ratio lambda(t|Xi)/lambda(t|Xj)=exp(Xi*beta)/exp(Xj*beta) does not depend on t.

Valentin



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