Classical ML

Cross-Validation

Estimating generalisation by repeatedly training on some folds and evaluating on the held-out fold.

Why interviewers ask about it

Plain k-fold assumes exchangeable rows. Time needs TimeSeriesSplit with purging, grouped data needs GroupKFold. The rule: the validation split must simulate the production split.

Data Leakage

Any information present at training time that will not be available at prediction time - from the target, from the future, from preprocessing fitted on the full dataset, or from entity overlap across splits.

This term is part of the free AI/ML Engineer interview preparation module - browse the full glossary for every definition.

Why interviewers ask about it

Related terms

Data Leakage

Why interviewers ask about it

Related terms

Data Leakage