Hello @chrishy,
I see. This is due to how decision tree (algorithm) works. You have small sample so tree simply stops growing If you set minimum number of records per node to one (1) you’ll probably see another (nominal) level in your tree…
Here are couple of thoughts on predictive modelling with small data sets from KNIME Community exprerts:
And how knows, maybe they join discussion and provide their opinion/ideas on data set provided
Br,
Ivan