SECAI Core · phase 15 of 15

Data drift

A phenomenon where the statistical properties of input data change over time, potentially reducing the accuracy and reliability of machine learning models or analytical systems.

The Explain card

Plain English
Data drift happens when the statistical properties of the input data a model receives change over time, so the model is seeing a world it was not trained on and its accuracy quietly declines.
Example
A phishing detection model trained on human-written email is increasingly fed messages written by generative AI. The vocabulary and structure of incoming mail shift, and detection rates fall without any change to the model.
Why it matters
Drift degrades defences silently and can be induced deliberately by attackers who feed a system unusual inputs. Monitoring input distributions is how you notice.
Hook
The map is the same, but the territory moved.

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.