[Limdep Nlogit List] Question on MVPROBIT Command

[William Greene]

Jason.  mu5 = 1 and mu2 = mu4 do not accomplish what you are trying to do.
These
constraints will force certain probabilities to equal zero or be negative.
I can't tell what
you are restricting, but in order for the model to be kosher, you must have
-inf < 0 <  mu1 < mu2 < mu3 <mu4 < mu 5 < +inf. If mu5 = 1 but mu4 > 1,
then your
model produces zero probabilities.  Likewise, forcing mu2 = mu4 will make a
mess of
things. You can't have mu2 = mu4 and have mu3 < mu4 and mu3 > mu2.
Regards,
Bill Greene


On Fri, May 7, 2021 at 6:32 PM Jason Bergtold <bergtold at ksu.edu> wrote:

> Dear Group:
>
> I am trying to run a Random Valuations Model following Wang and in Alberni
> et al (2003) (Analysis of contingent valuation data with multiple bids and
> response options allowing respondents to express uncertainty." I have a
> ordered response variable with 7 ordered categories from definitely no to
> definitely yes. I am modeling this using an ordered Probit model. The base
> model would estimate 7 threshold values with the first and last being set
> to -inf and inf, respectively. The middle 5 threshold values for the model,
> call them mu1 < mu2 < mu 3 <mu4 < mu 5. I want to set two restrictions on
> the model that mu 1 - mu5 = 0 and mu2 - mu 4 = 0, to make the estimation of
> the threshold parameters "symmetric". I am wondering how to impose this
> restriction using the Ordered command.
>
> Regards,
>
> Jason
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-- 
William Greene
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Stern School of Business, New York University
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