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Re: st: "time ratios" and "hazard ratios"

Subject   Re: st: "time ratios" and "hazard ratios"
Date   Thu, 14 May 2009 11:36:06 -0400



I think that's what I already specified, but this time I copied it
right from the link on Stephen's  web page, which is:

And the book is "lecture notes manuscript"  under "Other related
materials, including Lecture notes"


On Thu, May 14, 2009 at 11:25 AM, Martin Weiss <> wrote:
> <>
> The link to the book does not do much good for me. Is there an alternative?
> Martin
> -----Ursprüngliche Nachricht-----
> Von:
> [] Im Auftrag von
> Gesendet: Donnerstag, 14. Mai 2009 16:58
> An:
> Betreff: Re: st: "time ratios" and "hazard ratios"
> --
> "can I take the multiplicative inverse of the time ratio and report it
> as a hazard ratio?"
> No, The (log) Weibull is the  only probability distribution for which
> this is true.
> It's a good idea to consider multiple probability distributions, as
> you have done. but reporting the regression results is not enough.
> Have you evidence that these distributions fit the data?  (using a
> -linktest- or diagnostic plots, for example); that one fits any better
> or worse than the others?  You can compare directly the likelihoods of
> the log-logistic and log-normal, and those of the log-normal and
> Weibull models.
> For hazard ratio models, I rarely see anything but a Cox model these
> days, because the Weibull has a very restrictive shape. Patrick
> Royston's -stpm-  (from SSC) offers a flexible parametric version.
> For the log-linear regression models , the generalized Gamma in Stata
> has the most flexible shape, and its likelihood can be compared
> directly to those of the Weibull and log-normal.   See:  Stephen
> Jenkins's  book “Survival Analysis”, available from his website
> (
> v6.pdf
> ).
>  -Steve
> On Wed, May 13, 2009 at 7:16 PM, Emory Morrison
> <> wrote:
>> I am reporting different specifications of event history models within the
> same paper.
>> In some of the models (for example the log logistic specification and the
> log normal specification) stata reports coefficients as time ratios.
>> In the Weibull model stata report coefficients as hazard ratios.
>> While the direction of effects are clearly inverted in these two ways of
> reporting the coefficients, I need to know if these coefficients are
> precisely inverse.  In other words, can I take the multiplicative inverse of
> the time ratio and report it as a hazard ratio?
>> It would be very helpful in writing up the results of the paper, if the
> coefficients could be read and interpreted in a standardized fashion.

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