Comparing Different Models on New Data

[rohanchauhan]

Hi,

Let’s say I have

model A which is fit on data A’
model B which is fit on combined data A’ and B’

I want to compare model A and B. Apart from WAIC, how can I evaluate these two models on data C’ ? I cannot use LOO-CV.

Br,
Rohan

[nonparametric]

How about Root mean square deviation for each model on C. (https://en.m.wikipedia.org/wiki/Root-mean-square_deviation)