[Limdep Nlogit List] problem solved: thanks!
John C. Whitehead
john.c.whitehead at gmail.com
Tue Mar 24 03:15:55 EST 2009
Hi all,
Last week I sent the message below to this list. I received a number of
suggestions, each of which solved the problem:
1. scale up X2, X3, and X4 (I multiplied by 1000)
2. use the SAS results as starting values
3. add ;ALG=BFGS
I'm now using #3 and cranking through LCLOGIT and RPLOGIT models with no
problems.
Many thanks!
John Whitehead
----- Original Message -----
From: "John C. Whitehead" <john.c.whitehead at gmail.com>
To: "Limdep and Nlogit Mailing List" <limdep at limdep.itls.usyd.edu.au>
Sent: Saturday, March 21, 2009 11:36:59 AM GMT -05:00 US/Canada Eastern
Subject: [Limdep Nlogit List] nlogit with many alternatives
Hi All,
I'm trying to estimate conditional and nested logit models in NLOGIT. I have
1086 cases and 71 alternatives (77106 lines of data). The model is fairly
simple with only 5 independent variables:
Var Mean Min Max
X1 234 .60 777
X2 .023 .00 4.500
X3 .055 .00 2.85
X4 .018 .00 1.46
X5 2.85 1.38 4.98
When I estimate the CL and NL models with only X1, X2 and X5 I'm able to
replicate my results from SAS PROC MDC. However, when I add X3 and X4 my
estimates blow up:
|Variable| Coefficient | Standard Error |b/St.Er.|P[|Z|>z]|
+--------+--------------+----------------+--------+--------+
X1 | -.52294252 .00037816 ******** .0000
X2 | .162233D+14 .10083492 ******** .0000
X3 | .159318D+07 .11121567 ******** .0000
X4 | 1231.81419 .14232936 8654.674 .0000
X5 | 20.6940287 .05183529 399.227 .0000
I've tried scaling down X1 by dividing by 100 (no luck). The full model runs
just fine as OLS and Probit models in LIMDEP.
Any ideas about what I might be doing wrong?
Thanks for any help,
John Whitehead
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