On Fri, 13 Aug 2010, Maha Bakoben wrote:
Hi,
I'm trying to fit a multinomial logistic regression to my data which
consists of 5 discrete variables (scales 1:10) and 1000 observations.
I get the following error:
Error in `row.names<-.data.frame`(`*tmp*`, value = c("NA.NA", "NA.NA", :
duplicate 'row.names' are not allowed
In addition: Warning message:
non-unique value when setting 'row.names': ?NA.NA?
My code:
flevel1$Q120<-as.factor(flevel1$Q120)
MData<-mlogit.data(flevel1, varying=NULL,choice="Q120", shape="wide")
LogitModel<-mlogit(flevel1$Q120~1|flevel1$Q92, data=MData)
It's hard to say what you do wrong because you don't provide a
reproducible example. (Please see the posting guide, linked at the end of
this e-mail, for good posting practices.)
But it certainly looks suspicious that you force mlogit to use the
variables from flevel1 but provide data = MData. Try to do
mlogit(Q120 ~ 1 | Q92, data = MData)
In general, it is recommended to use
y ~ x, data = mydata
in R, where "mydata" contains (the appropriate version of y and x). It
typically leads to identical results as
mydata$y ~ mydata$x
which is, however, less elegant, especially if more variables are
involved. But using
otherdata$y ~ otherdata$x, data = mydata
is very likely to lead to confusion...
hth,
Z
MData[1:10,]
Q56 Q92 Q102 Q119 Q120
1.1 10 7 10 10 FALSE
1.10 10 7 10 10 TRUE
1.2 10 7 10 10 FALSE
1.3 10 7 10 10 FALSE
1.4 10 7 10 10 FALSE
1.5 10 7 10 10 FALSE
1.6 10 7 10 10 FALSE
1.7 10 7 10 10 FALSE
1.8 10 7 10 10 FALSE
1.9 10 7 10 10 FALSE
Your help will be greatly appreciated.
Maha
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