[Limdep Nlogit List] Nested Logit 51 choices

[Martin, Shane L.]

Hello,

I am currently attempting to estimate a nested logit with choice specific data.  That is, all consumers are representative consumers because I don't know anything about them.  I only know (a lot of) information about the choices that they make.

Essentially, I am doing a conditional logit model, but with a nesting structure.  Consumers choose between nonstop and one-stop flights.  The nonstop flight choice results in a degenerate branch.  Within the one-stop flight branch, there are up to 50 choices, though in practice, nobody faces the full choice set.  Nevertheless, there is a universal choice set.  My data include airfare, distance, circuity, # of runways at the hub airport (n/a for nonstop flights), and some other stuff.  NIJ indicates the number of choices faced by the individual for those lines of data.  For each individual, there are NIJ lines of data with chosen=1 for one line and chosen=0 for NIJ-1 lines of data.

When I run the following command, I get error:
Error    71: Variable list contains a name not in the expected table.
Error   539: Variable list: The unidentifiable string is 51
Error  1012: A choice label in a branch spec. is not in ;CHOICES list
Error  1012: A choice label in a branch spec. is not in ;CHOICES list

Nlogit
;LHS=Chosen, nij
;CHOICES=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51
;tree=ns(51),ws(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50)
;MODEL:
U(ws)=bf*RFARE+bd*ITDIST+bc*CIRC+br*RUNWAYS+bn*NONSTOP/
U(ns)=bf*RFARE+bd*ITDIST+bc*CIRC+bn*NONSTOP$

If I instead run the following command (notice the slightly different tree structure), I get error:
Error  1009: Expected [ in limb specification was not found.
Error  1009: Expected [ in limb specification was not found.

Nlogit
;LHS=Chosen, nij
;CHOICES=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51
;tree=Type[ns(51),ws(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50)]
;MODEL:
U(ws)=bf*RFARE+bd*ITDIST+bc*CIRC+br*RUNWAYS+bn*NONSTOP/
U(ns)=bf*RFARE+bd*ITDIST+bc*CIRC+bn*NONSTOP$


I was hoping that someone on this list could shed some light on this issue.  Thanks. --Shane

Shane L. Martin, Ph.D.
Economist
The MITRE Corporation
Center for Advanced Aviation System Development
703-983-3902
slmartin at mitre.org