[Limdep Nlogit List] Nested logit model: unfeasible results
Sigitas Karpavicius
s.karpavicius at unsw.edu.au
Wed Aug 12 17:01:51 EST 2009
Dear all,
I would like to estimate nested logit model (2 levels; one degenerate
branch). My data includes no choice-specific variables, i.e. all
observations are invariant individual characteristics that do not depend on
choice. In addition, if degenerate branch is chosen, some variables are
always equal to 0. If I include any of the latter variables in the lower
level, then in some cases (not all) I get weird results for upper level. For
example, standard errors are very large and p-values are equal to 1:
+--------+--------------+----------------+--------+--------+
|Variable| Coefficient | Standard Error |b/St.Er.|P[|Z|>z]|
+--------+--------------+----------------+--------+--------+
WW8 | -.00821288 .518906D+10 .000 1.0000
WW9 | 8.36713407 .331536D+12 .000 1.0000
WW10 | 7.01247444 .203552D+12 .000 1.0000
I was wondering whether I get such results because of the date set or
because of the degenerate branch, or because of the both. Is there any way I
could get feasible values?
In addition, I would like to ask how to transform a categorical variable
into a set of dummy variables. The categorical variable has more than 100
values and "CREATE ;expand(...)$" does not work. In output window, I get the
message: "Error 711: variable in EXPAND is not an integer from 1 to 100".
Alternatively, I could run "CREATE ;expand(...)$" several times.
Any advice would be appreciated.
Best regards,
Sigitas Karpavicius
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