[R] error in summary.Design

[Frank E Harrell Jr]

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