Advanced – AI & ML Testing
Model Drift – ISTQB Definition
Last Updated: July 12, 2026 · SoftwareTestPilot QA Team
Official ISTQB Definition
Degradation of model accuracy over time due to changes in the underlying data distribution.
In simple words
When an AI model gets worse over time because the real world changed.
Exam tip
Monitor drift with statistical tests (KS, PSI) on input features and periodic re-evaluation on holdout data.
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