[Limdep Nlogit List] Is a multinomial logit model with selection applicable here?

[James Giller]

Thank you William and Timothy. I will adjust my modeling approach.

On Wed, Feb 16, 2022, 6:57 AM Haab, Timothy <haab.1 at osu.edu> wrote:

> James, looks like you will need a nested model (logit?) with the top level
> nest being trip/no trip, and then conditional on trip, mode.
>
> -----Original Message-----
> From: limdep-bounces at mailman.sydney.edu.au <
> limdep-bounces at mailman.sydney.edu.au> On Behalf Of James Giller via Limdep
> Sent: Tuesday, February 15, 2022 4:20 PM
> To: limdep at mailman.sydney.edu.au
> Subject: [Limdep Nlogit List] Is a multinomial logit model with selection
> applicable here?
>
> Hi,
>
> My dependent variable is based on travel mode choice survey data, and it
> has a value for "make no trip at all" as well as values for various modes,
> car, transit, taxi, walking, etc. The mode is only observed if the survey
> participant would make a trip, which made me consider a sample selection
> model.
>
> My dependent variable Y has the following values:
> 0 = transit
> 1 = car
> 2 = carpool
> 3 = taxi
> 4 = walking
> 5 = other
> 6 = no trip
>
> I created another variable DOTRIP, which is 0 if Y = 6, and 1 otherwise.
>
> I then tried to estimate the following model PROBIT ; Lhs = DOTRIP ; Rhs =
> <explanators> ; Hold $ MLOGIT ; Lhs = Y ; Rhs = <explanators> ; Selection ;
> Pts = 25; Halton $
>
> The above model on the data set as explained returned an error message
> that there is insufficient variation in the dependent variable during the
> MLOGIT part. I think this is because the value 6 (no trip) is possible for
> Y, but none of the observations would be selected in the selection step.
>
> Am I correct in specifying a model with sample selection in this case? Or
> should I take a different approach to account for the individuals first
> deciding whether or not to travel, then by which mode?
>
> Is there some way to rearrange my data so that the above model will work?
>
> Thank you.
> James.
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