[Limdep Nlogit List] Pds specification for choice modeling with unbalanced datasets

[William Greene]

Iris. The unbalanced choice model has a complicated data set.  Observations
(rows of data) are grouped
within a choice task, and there is a panel of choice tasks.  NLOGIT handles
this case by borrowing part of
the process from the ordinary panel data routine.  The match of the data to
the specification ends up being
checked twice, once as if it were an ordinary panel and a second time by
the RPLogit routine. (There is a
description in Section N29.10 in the manual how this is set up - you would
have used the guide there to set
up the data.)  The diagnostic you received is generated by the first pass
through the data.  But, this can be
ignored.  It is the second pass that actually tallies the panel setup for
RPLogit.  So, if your data are arranged
as the estimator expects, you can ignore that diagnostic. (It should be a
warning, not an error.)
Regards,
Bill Greene

On Tue, Jul 27, 2021 at 6:25 PM Iris Vanermen <iris.vanermen at kuleuven.be>
wrote:

> Dear Mr., Ms.,
>
> I am trying to estimate a random parameters logit model in which the
> number of choice tasks differs between individuals. For this, I am trying
> to adjust the Pds specification with a variable indicating the number of
> choice cards per individual but I get following error: "Error 1081:
> Mismatch of # indivs. and number implied by groups" that I do not seem to
> be able to resolve. How should I specify Pds in case of different number of
> choice cards per individual?
>
> Many thanks!
> Best regards,
> Iris Vanermen
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-- 
William Greene
Department of Economics, emeritus
Stern School of Business, New York University
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