I'm trying to make predictions based on customer service samples using randomForest and GBM, I'm leveraging on 2 stage modeling, i.e. 1st stage to predict whether customer will react or not, 2nd stage will predict how much they will spend. My 2nd stage model is training on those who spend>0 following is the prediction histogram vs actual test histogram (pink is actual, blue is prediction)
my question is why they deviates this far? I have checked my training samples, their histogram is same as test samples, any way that I can improve??