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Re: st: interpreting output in survival analysis


From   Maarten Buis <maartenlbuis@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: interpreting output in survival analysis
Date   Mon, 30 May 2011 09:09:14 +0200

On Sun, May 29, 2011 at 7:40 PM, Yusvita Triwiadhian S. wrote:
> i have a problem to interpret output of survival analysis specially
> output of gompertz regression gamma frailty..
>
>   t        |      Coef.                 Std. Err.      z    P>|z|
> [95% Conf. Interval]
> gamma |   .0007606   .         0011992     0.63   0.526    -.0015898     .003111
>
> please let me know, what it means of gamma and how about if p-value of
> gamma >0.5?

The parameter gamma is part of the Gompertz model, and confusingly not
of the gamma frailty sub-model. If the gamma equals 0, the Gompertz
distribution is equal to the exponential distribution. In other words,
in that case the baseline hazard does not change over time. In your
case the gamma is very small and the statistical test clearly
indicates that the hypothesis that gamma equals 0 cannot be rejected,
so I would conclude that the baseline hazard is constant.

Hope this helps,
Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------

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