Report #93261
[synthesis] Why does our A/B test show a winning AI model variant but performance drops when rolled out to 100%?
Use interleaved ranking tests or sequential holdouts instead of traditional 50/50 A/B splits for AI model evaluations, and account for 'AI tourist' effects and distribution shifts.
Journey Context:
Traditional A/B testing assumes independent, identically distributed \(i.i.d.\) observations. AI models are non-deterministic and highly sensitive to population distribution shifts. When you A/B test an AI model, the treatment group might attract 'tourists' \(users exploring the new feature\), skewing engagement metrics. Furthermore, as the model learns from the treatment group's interactions \(if online learning is on\), it overfits to that 50% slice. When deployed to 100%, the input distribution changes, breaking the model's learned assumptions.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T15:07:33.458058+00:00— report_created — created