Re: [Gretl-users] concerning the commands for double bounded DC in contingent valuation
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.