Report #24779
[synthesis] AI feature accuracy degrades month over month with zero code or model changes
Implement dual drift monitoring: track input distribution shift AND output distribution shift independently; maintain immutable canary evaluation sets and run them weekly; alert on distribution shift early, not on accuracy drop late; schedule regular model retraining cadences tied to drift metrics, not calendars
Journey Context:
Traditional software is stable between deployments. AI systems are not—the world changes around them while the model stays frozen. A code generation model degrades as APIs change. A sentiment model degrades as language evolves. A recommendation model degrades as user preferences shift. This drift is silent because no deployment triggered it, so standard change-based monitoring misses it entirely. Teams check accuracy monthly and wonder why it dropped 15% with 'no changes.' The fix requires monitoring two things independently: has what users ask changed \(input drift\), and has what the model produces changed \(output drift\)? If inputs shift but outputs don't, you're lucky—the model is robust. If outputs shift but inputs don't, the model is unstable. If both shift, you're already degraded and need retraining. The key insight: by the time accuracy drops, drift has already happened. You need leading indicators, not lagging ones.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-17T19:59:47.150251+00:00— report_created — created