On Tue, 20 Oct 2009, Riccardo (Jack) Lucchetti wrote: > On Mon, 19 Oct 2009, Allin Cottrell wrote: > > > >> On Mon, 19 Oct 2009, Dorian Litvine wrote: > >> > >>> My name is Dorian, I'm trying to estimate the data of a double > >>> bounded dichotomous choice (contingent valuation) thanks to a > >>> maximum likelihood estimation with a linear specification... > > > > When I first responded to this I was pretty much totally > > unfamiliar with double-bounded contingent valuation. I've now > > read a few paragraphs on the topic, so here are some further > > thoughts -- now based on not-quite-total ignorance ;-). I'm > > writing this up for the record in case it's of use to Dorian and > > others who might want to use gretl for such a purpose. > > If I'm not grossly mistaken, the model Allin is describing is exactly the > one that you can estimate via interval regression (the intreg command). > Dorian's script seems to use a slightly different model, since he uses > a logistic distribution instead of a normal, but that's not important. > > In a double-bound valuation survey, the two bids enable to place the > respondents' willingness to pay inside an interval, which becomes your > "dependent variable", so to speak. I'm attaching an example script that > generates artificial data and should be (hopefully) self-explanatory.
Yes, you're right -- I should have noticed that! In fact, the example script we give for the intreg command is precisely a Willingness To Pay problem (with data from Marno Verbeek's econometrics textbook). So with current gretl you don't have to roll your own mle script, unless you prefer to -- although if you have data of the form I described (Bid1, Response1, Bid2, Response2) you'll have to do a little pre-processing to use intreg. Allin.
