# Boost a weak learner

Model / supervised

A variant of [Combine models](https://meridian.online/operations/combine-models).

Wrap any learner and train it round after round, reweighting rows or fitting the errors of earlier rounds, and add the rounds into one model; gradient boosted trees fix the learner as a tree.

Page: <https://meridian.online/operations/combine-models/boost-a-weak-learner>

## Status

Not built yet.

arcform does not do this yet. [Its place on the roadmap](https://meridian.online/roadmap#combine-models)

## What other tools call it

Meridian's classification; an independent blind rating agreed on 95.7% of 324 rows (variant, version 3).

- KNIME Analytics Platform: [`Boosting Learner Loop End`](https://api.hub.knime.com/nodes/*a36eXM94uKOrTIlo?details=full) (read 2026-09-27)
- KNIME Analytics Platform: [`Boosting Learner Loop Start`](https://api.hub.knime.com/nodes/*io0onqmszrZBZI8q?details=full) (read 2026-09-27)
- mlpack: [`AdaBoost`](https://www.mlpack.org/doc/user/modeling.html) (read 2026-09-27)
- mlpack: [`mlpack_adaboost_train`](https://duckdb.org/community_extensions/extensions/mlpack) (read 2026-09-27)
- RapidMiner Studio: [`AdaBoost`](https://docs.rapidminer.com/latest/studio/operators/modeling/predictive/ensembles/adaboost.html) (read 2026-09-27)
- RapidMiner Studio: [`Additive Regression`](https://docs.rapidminer.com/latest/studio/operators/modeling/predictive/ensembles/additive_regression.html) (read 2026-09-27)
- RapidMiner Studio: [`Bayesian Boosting`](https://docs.rapidminer.com/latest/studio/operators/modeling/predictive/ensembles/bayesian_boosting.html) (read 2026-09-27)