Error in ConfusionMatrix the data and reference factors must have the same number of levels

Question

I\'ve trained a tree model with R caret. I\'m now trying to generate a confusion matrix and keep getting the following error:

Error in confusionMatrix

Answer 1

If your data contains NAs then sometimes it will be considered as a factor level,So omit these NAs initially

DF = na.omit(DF)

Then,if your model fit is predicting some incorrect level,then it is better to use tables

confusionMatrix(table(Arg1, Arg2))