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(psa)
> 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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>
--
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University