Classical ML
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.
Why interviewers ask about it
0.99 AUC on a business problem is a leakage alarm, not a success. Adversarial validation and single-feature AUC screens are the detectors to name.
Related terms
This term is part of the free AI/ML Engineer interview preparation module - browse the full glossary for every definition.