# Leakage Prevention

> Source: https://sukruyusufkaya.com/en/glossary/veri-sizintisi-onleme
> Updated: 2026-05-13T21:13:04.534Z
> Type: glossary
> Category: veri-bilimi-ve-veri-yonetimi
**TLDR:** A preprocessing discipline that prevents information unavailable at real usage time from leaking into model training.

<p>Leakage prevention is one of the most critical engineering disciplines in preprocessing and modeling. Scaling before the train-test split, using variables too close to the target, or incorporating future information in time-based problems all create leakage. Such mistakes make models appear much stronger than they actually are. Strong leakage prevention requires transformations to be applied in the correct order within a pipeline and time logic to be preserved rigorously. Reliable modeling depends on honest data flow design before it depends on algorithm choice.</p>