R help - Feb 2015 - #library(party) - Compare predicted results for ctree

Hello,

I've created a ctree model called fit using 15 input variables for a factor
predicted variable Response (YES/NO).
When I run the following :
table(predict(fit2), training_data$response) 
I get the following result:

     NO   YES 
NO  48694   480 
YES     0     0

It appears that the NO responses are predicted with 100% accuracy and the YES
response are predicted with 0% accuracy.

Why is this happening? It's because of my data or it's something in
ctree algorithm?

Thanks!
Rodica

On Mon, 16 Feb 2015, Rodica Coderie via R-help wrote:
> Hello,
>
> I've created a ctree model called fit using 15 input variables for a
factor predicted variable Response (YES/NO).
> When I run the following :
> table(predict(fit2), training_data$response)
> I get the following result:
>
>     NO   YES
> NO  48694   480
> YES     0     0
>
> It appears that the NO responses are predicted with 100% accuracy and 
> the YES response are predicted with 0% accuracy.
>
> Why is this happening? It's because of my data or it's something in
> ctree algorithm?
Your data has less than 1% of YES observations and I would guess that the 
tree cannot separate these in a way such that majority voting gives a YES 
prediction. You might consider a different cutoff (other than 50%) or 
downsampling the NO observations.
> Thanks!
> Rodica
>
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