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st: nlogit nesting scheme for 3-level degenerate model: data structure


From   John Fulton <[email protected]>
To   [email protected]
Subject   st: nlogit nesting scheme for 3-level degenerate model: data structure
Date   Wed, 03 Jan 2007 19:09:43 -0500

Thanks. I did not find Heiss's example model L(N) helpful, for reasons I won't go into here.

Here's the form of my data with a hypothetical example: a study of choices between cake and various kinds of pie. Please ignore the independent variables - they're completely made up and I include them only to clarify the syntax.

The nlogittree output would be:
top---->bottom
dessert type pie
__________________________________
cake cake chocolate
pie fruit_pie cherry
peach
cream_pie banana
coconut
the model would be:
nlogit chosen (pie=calories) (type=pie_rating) (dessert=freshness), group(person_id)

As you see, the "cake" nest is degenerate. My model kicks out an error:
"Equation/parameter /cake/ multiply defined"
Is there a "quick fix" for this error? Or do I need to do some restructuring of my data?
Thank you,
John.



Anders Alexandersson wrote:

To structure the data for a degenerate nest in a 3-level
non-normalized nlogit model, see pages 12-14 in Heiss' draft online
article (model L) or pages 250-251 in Heiss' SJ article (model N); The
syntax for nlogitdn is the same as for nlogit.
...
Anders Alexandersson
[email protected]

John Fulton <[email protected]> wrote:
...Assuming nlogit is appropriate, how should I structure data for a
degenerate nest in a 3-level model?
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