Dear Frank and rest of list, please accept my apologies for not giving
full details of my analysis in my previous email. I have been working
on this problem and I think my error comes from the class of my
variables and the way I defined the model, and I seemed to be able to
solve it...
d = datadist(VAR2,VAR3,VAR4,VAR5,VAR6,VAR7,VAR8)
options(datadist="d")
but then I called the model on factors
mymodel = lrm(factor(VAR1)~VAR2+factor(VAR3)+
factor(VAR4)+factor(VAR5)+factor(VAR6)+factor(VAR7)+factor(VAR8),
mydata, method="lrm.fit")
Storing the variables in mydata as factors and recomputing "d" solves
the mistake
VAR1 = factor(mydata$VAR1)
VAR3 = factor(mydata$VAR3)
VAR4 = factor(mydata$VAR4)
VAR5 = factor(mydata$VAR5)
VAR6 = factor(mydata$VAR6)
VAR7 = factor(mydata$VAR7)
VAR8 = factor(mydata$VAR8)
and
VAR2 = mydata$VAR2
dd = datadist(VAR2, VAR3,VAR4,VAR5,VAR6,VAR7,VAR8)
options(datadist="dd")
mymodel2 = lrm(VAR1~VAR2+VAR3+VAR4+VAR5+VAR6+VAR7+VAR8, method="lrm.fit")
This time, summary.Design() works
Thanks for the useful comments
David
Frank E Harrell Jr <[EMAIL PROTECTED]> ha escrito:
DAVID ARTETA GARCIA wrote:
Dear list,
after fitting an lrm with the Design package (stored as "mymodel")
I try running a summary, but I get the following error:
dim(mydata)
[1] 235 9
names(mydata)
[1] "id" "VAR1" "VAR2" "VAR3" "VAR4" "VAR5" "VAR6" "VAR7" "VAR8"
summary(mymodel)
What is mymodel? Please read the posting guide by providing a full
reproducible example. You can't expect people to help if you want to
keep your code a secret.
Error in `contrasts<-`(`*tmp*`, value = "contr.treatment") :
contrasts can be applied only to factors with 2 or more levels
but,
VAR1 is my dependent
nlevels(factor(VAR1))
[1] 2
This does not tell you about VAR1. It tells you about VAR1 after
converting it to a factor variable.
Frank
VAR2 is continuous
summary(VAR2)
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.90 6.05 8.40 10.99 13.15 59.70
and for the remaining variables...
nlevels(factor(VAR3))
[1] 2
nlevels(factor(VAR4))
[1] 2
nlevels(factor(VAR5))
[1] 3
nlevels(factor(VAR6))
[1] 2
nlevels(factor(VAR7))
[1] 2
nlevels(factor(VAR8))
[1] 2
What I am missing?
Thanks in advance,
David
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
