Ensemble Learning

POLI_SCI 490

Machine Learning in Political Science

Plan for today

Coding

  • Model stacking

Discussion

  • Ensemble learning + Reading

Coding

https://github.com/gustavo-diaz/ps490ml/blob/main/scripts/stack.qmd

Discussion

Ensemble approaches

  1. Bagging (+ random forests)

  2. Boosting

  3. Bayesian models (e.g. BART)

  4. Stacking

Questions

When do you need an ensemble?

Which approach to ensembles do you prefer?

What is better?

  1. Fine-tuning a single model
  2. Stacking many different kinds of models