st: nlogit: at least one alternative of variable is contained in muliple alternatives of variable; this is not allowed

[Stefan Bernhard <stefanbernhard88@gmail.com>]

dear statalisters,

-nlogit- seems to be a topic that is not getting much replies from statalist.

I can only find one archive entry for this error and that is a dead end.

"at least one alternative of connection is contained in muliple
alternatives of type;
this is not allowed"

First, there is a spelling error in there...
Second, what is the error trying to tell me and what am I supposed to
do to avoid it?

I have a 4-level nlogit model, where each case has a choice over 115
alternative internet tariffs (one of those being the base "no
internet").

The choice levels are
lev1: internet: 1,0
lev2: type: 1,2,3
lev3: connection: 1,2,3
bottom level: tariff

where "type" is an indicator of the target group (low-end, average or
high-end user) and "connection" is the mode of connection (dsl, cable,
mobile).

I set up the data with 3 -nlogitgen- in the form:
nlogitgen internet = tariff(yes: 1 | 2 | ... , no: 0)
nlogitgen type = tariff(lowend: ... ,normal: ... ,highend: ... ,no: 0)
nlogitgen connection = tariff(dsl: ...,cable: ...,mobile: ... ,no: 0)

nlogittree tariff connection type internet

nlogit choice price bandwidth volume /*
*/ || internet: , base(no) /*
*/ || type: age education , base(no) /*
*/ || connection: household_size , base(no) /*
*/ || tariff: , case(hh_id)


I would really appreciate some clarification on the meaning of this error.

best, stefan bernhard,
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