How might this be combined with a training/testing data splitting paradigm, or even using an ML model?
This [6] is a more in depth look at hierarchical / multi-level modeling. The prediction section [7] specifically goes over cross validation and inference.
[1] https://www.tensorflow.org/probability/examples/Multilevel_M... [2] https://pyro.ai/examples/forecasting_iii.html [3] http://edwardlib.org/ [4] https://mc-stan.org/ [5] https://docs.pymc.io/ [6] https://docs.pymc.io/notebooks/multilevel_modeling.html [7] https://docs.pymc.io/notebooks/multilevel_modeling.html#Pred...