Dear All,
I want to thank both Roberto and Jesper for their great comments (and
sorry for not being to do this sooner because I was bounced out the list
for no obvious reasons).
I have something else to say about the the AFT vs. PH. Based on what I
know, there is no way to parameterize ordinary log-logistic hazard model
(as implmented in Stata and many other packages) as PH. But TDA
implements an extension of the ordinary log-logistic hazard model
proposed by Bruederl&Diekmann (1995). They replace the scale parameter
with two that represent the "timing effect" and the "intensity effect".
The timing effect can only be parameterized as AFT, but the intensity
effect can be parameterized either as AFT and PH.
Again, thank you very much for the comments.
Shige Song
Department of Sociology, UCLA
Reference:
Bruederl, J., and A. Diekmann. 1995. "The Log-Logistic Rate Model - 2 Generalizations with an Application to Demographic-Data." Sociological Methods & Research 24:158-186.
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