SECAI Core · phase 15 of 15

Model drift

A phenomenon wherein the statistical properties of the target variable or features of a machine learning model change over time, leading to a reduction in model performance.

The Explain card

Plain English
Model drift is the decline in a model's performance over time because the statistical relationships it learned, between its features and its target, no longer hold in the real world.
Example
A fraud model learned that late-night foreign transactions signal fraud. After the business expands internationally, that pattern becomes normal behaviour, and the model starts flagging legitimate customers while missing newer fraud types.
Why it matters
A drifting model gives false confidence. Defenders need scheduled performance checks and retraining triggers, because a model that was accurate at launch can become a liability.
Hook
The model did not change, the world did.

Where it sits in the deck

Phase 15: MLOps, Continuous Delivery, and Operational Resilience

Close the loop — operational practices, drift management, and delivery discipline that keep deployed AI systems healthy, current, and continuously improving.