st: Nested Logit Model

[Luis Felipe Correa Smits <felipe.correa.smits@gmail.com>]

Dear All,

I’m quite new to stata so I don’t know If I have a command or database
issue. So here I go:

I’m trying to solve a model for my thesis dissertation on the
probability for a pharmacy to enter and then locate in a Chilean
district. My ideal tree should be:


                 N
          /              \
        /                  \
      /                       \
Enter                Not Enter
   |                    /        |    \
   |                  /          |      \
   |                /            |        \
   0     Location=1       …      N

I generated the nlgoit tree with the district=0 for the decision not
to enter the industry, and all the observed districts for the decision
to enter (nlogitgen type=district (No: 0, Yes: 1|…|N). Then I
generated the “chosen” variable based on whether there’s a pharmacy on
the district or not.

Then I tried to run the regression (nlogit   chosen
number_of_stores_pharmacy_chain1    number_of_stores_pharmacy_chain2
 number_of_stores_pharmacy_chain3
number_of_stores_independent_pharmacies
type_of_competitor_base_on_distance[inmediate; nearby; far away]
population_between_0_to_5_years_old  population_more_than_65_years_old
 median_rent  district_area[sq miles] business_density||type:
income_per_capita urban_population rural_population||district:,
case(district_id)).

But I get:
note: 334 cases (1336 obs) dropped due to no positive outcome or
multiple positive outcomes per case
no cases remain after removing invalid observations
r(2000);


I don’t know what I’m doing wrong. Can anyone help me please?

Thanks!


Best Regards

Felipe Correa

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