Glossary term
Glossary term
Governance and Compliance
A gradual or sudden change in model performance over time, often due to changes in data, environment, user behavior, or concept relationships. It should be detected, investigated, and addressed through retraining, controls, or retirement. Drift detection should be linked to acceptance thresholds, escalation rules, and decisions about retraining, prompt adjustment, fallback, or temporary suspension.
Zillow Offers' November 2021 shutdown was caused by model drift in its home valuation algorithm as housing market conditions changed rapidly.
COVID-19 disrupted demand forecasting models at retailers like Walmart and supply chain systems globally, a widely cited drift event.
Carrefour's AI inventory management adapted to drift through automated retraining pipelines documented in 2023 case studies.