st: Re: Interval censored survival model

[plumsh <plumsh119@gmail.com>]

> The manual (Page 20 of the Survival Analysis section) explicitly states
> that there are no discrete-time models in Stata. The only user-made codes
> for grouped (interval censored) data that I found are pgmhaz(8), hshaz, and
> intcens. The first two don’t accommodate intervals of unequal length and,
> unfortunately, the model and the syntax for INTCENS seems a little obscure
> (at least to me at this point).
>
> My setup: land plots in agricultural use (farmland) have been converted to
> residential and other commercial uses. Observations on the same land parcel
> are recorded on, say, Jan 1 of 1980, 1997, 2005, and 2010 (same dates for
> all parcels in the sample). Thus, the intervals are of unequal length. Apart
> from that, we have stock sampling (the land has been farmed since a long
> time ago; no record when and it does not really matter).
>
> I want to do survival analysis using location (distance to beach, roads,
> schools), demographic (population density, mix, etc.), and economic (plenty)
> parcel attributes.
>
> The theory on Grouped Duration Data analysis (particularly the piecewise
> constant proportional hazard) is pretty straightforward (section 20.4 in
> Wooldridge, Econometric Analysis of Cross Section and Panel Data).
>
> Since I don’t have the time to write a readily working function for the ml
> command, I would greatly appreciate any advice on how to estimate my
> interval censored (grouped) data on land parcels. Pity they didn’t record
> exact conversion times. My only alternative now is probit/logit codes (I
> read most of the relevant posts on the Statalist archives).
>
> Regards
>
> Sheng

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