Franken, Jason R. <[email protected]>:
I think the reference does not apply to your case; I think you do not
want -truncreg- (or -heckman-? you don't specify whether the contract
length is the outcome or explanatory variable) because of the
normality assumption required. You have censoring in a survival
model--read the material at
http://www.iser.essex.ac.uk/iser/teaching/module-ec968 for starters.
For more help, you should be more specific about the model you hope to estimate.
On Thu, May 7, 2009 at 1:07 PM, Franken, Jason R. <[email protected]> wrote:
>
> Is there a user-written program appropriate for the type of truncated data discussed in Maddala (1983, p.165-170): "Limited-Dependent and Qualitative Variables in Econometrics"?
>
> I have data on contract duration for contracts observed in 2006 but signed at earlier dates. This means that I observe some contracts with a duration of ten years, but I do not observe a contract signed in the same year with a duration of 3 years (that is, it was binding for only 3 years). OLS estimates are therefore biased, and MLE is needed.
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