Jon's use of -xi:- here is really a side issue. While it's quite true
that factor variables in Stata 11 offer more power and flexibility than
did -xi:- it is equally true that -xi:- remains available and continues
to produce good results. It seems to me that Jon's question remains
essentially untouched by Martin's comment.
Nick
[email protected]
Martin Weiss
In the absence of a -version- statement, your code is problematic as it
still uses -xi- which has been superseded in Stata 11. Note the FAQ on
this
point.
I think you will get more/better answers if you frame your question in
terms
of the example in the help file...
Jon Heron
I have always believed that the regression estimates from a multinomial
logistic
regression model (MLOGIT) could be replicated through a set of simple
logit models with the appropriately derived binary outcomes.
Whilst attempting to demonstrate this fact for some teaching material
on
polytomous IRT that i am writing, I moved from my usual categorical
predictors to a continuous covariate + discovered that the above
equivalence
did not hold.
To ensure that this was not a fluke, I have since demonstrated that
with
the two simple models below, each with the same 4-level outcome and
4-level
predictor, the former can be replicated with logits, but not the
latter.
xi: mlogit ghq1 i.ghq3, baseoutcome(0)
mlogit ghq1 ghq3, baseoutcome(0)
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