[Limdep Nlogit List] Error 668: Error: N not a multiple of T

[William Greene]

Thao. If you have specified the LHS variables correctly for choice models
with
differing sized choice sets, then the appropriate number of periods for the
PDS
specification is the number of choices, which is 7, as you did.  The error
668
occurs before nlogit has resolved that this is a choice model, not an
ordinary panel.
In that case, the processing continues on to the choice model, where PDS=7
is
correct.  So, you can treat the 668 error as a warning.  The data are
organized
properly.  Resolution of the data setup takes two steps.  The warning takes
place
at the first, where nlogit is just counting the rows of data.
/Bill Greene

On Sun, Sep 20, 2020 at 9:37 PM Thao Thai via Limdep <
limdep at mailman.sydney.edu.au> wrote:

> Hi Nlogit user,
>
> In my data set, each respondent answered 4 DCE questions with 3
> alternatives and 3 DCE questions with 6 alternatives. To run the scaled MNL
> model, I specified: ;pds=7 but I got the error message:
>
> "Error    668: Error: N not a multiple of T. N=   23700. T=       7"
>
> I understand N is the total lines in the data: 790 * (4*3 + 3*6) = 23700
> which is obviously not a multiple of 7. However, each respondent does make
> 7 choices.
>
> Could you please let me know how I should make it right? Thank you so much.
>
> Best regards,
> Thao
> _______________________________________________
> Limdep site list
> Limdep at mailman.sydney.edu.au
> http://limdep.itls.usyd.edu.au
>
>

-- 
William Greene
Department of Economics, emeritus
Stern School of Business, New York University
44 West 4 St.
New York, NY, 10012
URL: https://protect-au.mimecast.com/s/7ScjCyojxQTOoxx0FZ9Roa?domain=people.stern.nyu.edu
Email: wgreene at stern.nyu.edu
Ph. +1.646.596.3296
Editor in Chief: Journal of Productivity Analysis
<https://protect-au.mimecast.com/s/t2lwCzvkyVCWq55xIXUy0g?domain=springer.com>
<https://protect-au.mimecast.com/s/t2lwCzvkyVCWq55xIXUy0g?domain=springer.com>
Editor in Chief: Foundations and Trends in Econometrics
Associate Editor: Economics Letters
Associate Editor: Journal of Business and Economic Statistics