This is forwarded on behalf of Jared Gross.
----------------------------------------------------
Please forgive my basic question; relative to most users on this list,
I'm
not very familiar with Stata.
I'm trying to use the nlogit command in Stata 10 to estimate a
degenerate
model of mergers and acquisitions. Unfortunately, I keep getting the
error
"no cases remain after removing invalid observations." Because I'm
pretty
sure I'm mis-specifying my model, and possibly don't have the cases
right,
I'm hoping someone here can help.
My data looks like the following:
Ticker Year Covariates GoesPrivate PublicTakeover Event
ContinuesIndep
A 1999 x 0 0
0 1
A 2000 x 0 1
1 0
B 1998 y 0 0
0 1
B 1999 z 0 0
0 1
B 2000 z 1 0
2 0
And the model I want to estimate is:
Company either (1) has ContinuesIndependently == 1 OR (2) is subject to
Event == 1 | Event == 2
If Event == 1 | Event == 2, then either (A) GoesPrivate == 1 OR (B)
PublicTakeover == 1,
so that I have a nested model in which the first logit determines
whether a
company continues in my data to the next year or exits through
"Takeover"
(i.e. Event == 1 | Event == 2); and then a second, degenerate stage in
which
the company, if Takeover == 1, either GoesPrivate == 1 or PublicTakeover
==
1.
How do I estimate this? I tried to use the following commands:
egen id = group(ticker)
nloitgen takeoverType = Event(Cont: 0, takeover: 1|2)
nlogit GoesPrivate covariates || takeoverType: other_covariates,
base(cont)
||, case(id)
I think my problem may be coming stemming from my use of ticker as the
case(id).
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