Re: st: interpreting coefficients in discrete time hazard model

["Daniel H. Simon" <dhs29@cornell.edu>]

Stephen - I just want to double-check, to be sure that I'm clear. The 
interpretation of a coefficient of 5 on ln(x) would be that the hazard rate 
increases by 5% as x increases by 1%. is that right? Thanks again. Daniel

At 11:37 AM 1/13/2003 +0000, you wrote:

> On Fri, 10 Jan 2003 13:51:37 -0500 Daniel Simon <dhs29@cornell.edu>
> wrote:
>
> > Hi - I am estimating a discrete time hazard model, using pgmhaz.  I have
> > several covariates that are in the form ln(x).  I'm wondering how to
> > interpret the coefficients on these variables.  Specifically, when i
> > exponentiate the estimated coefficient, b, what does exp(b) mean? For
> > example, if the coefficient b is equal to -5, and exp(-5) is .00674, then
> > does this say that a 1% change in x reduces the hazard by .99326?  Or 
> is it
> > something different?  Thanks. Daniel
>
> Why might you want to exponentiate the coeff on an explanatory variable
> that is in log form?  Since -pgmhaz- estimates proportional hazard
> regression models (using discrete time data), the model is of the form:
>         log(hazard_it) =  b'X_it + c'log(Y_it)
> with an additional gamma frailty term in -pgmhaz- Model 2.
> Hence the coefficient c may be interpreted as the elasticity of the
> hazard w.r.t. Y_it (or, if you will, the percentage change in the
> hazard given a one percent change in Y_it:)
> See the (pdf file) draft lecture notes at
> http://www.iser.essex.ac.uk/teaching/stephenj/ec968/index.php
>
>
> Stephen
> ----------------------
> Professor Stephen P. Jenkins <stephenj@essex.ac.uk>
> Institute for Social and Economic Research (ISER)
> University of Essex, Colchester, CO4 3SQ, UK
> Tel: +44 (0)1206 873374. Fax: +44 (0)1206 873151.
> http://www.iser.essex.ac.uk
>
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