An auditor is reviewing a production computer-vision system and must assess whether the team has implemented adequate monitoring for concept drift. Which TWO indicators should the auditor expect to be tracked on an ongoing basis? (Choose two.)
Trap 1: Total inference latency measured at the API gateway
Latency reflects infrastructure and serving performance, not whether the mapping from inputs to labels has changed. A model can serve quickly while silently degrading in accuracy, so latency monitoring, however useful operationally, does not indicate concept drift and should not be relied on for that purpose.
Trap 2: Count of active user accounts authorized to call the prediction…
The number of authorized accounts is an access-control and provisioning metric. It says nothing about whether the model's decision behaviour still matches the environment it was trained on, so it cannot serve as evidence of concept drift and is unrelated to the monitoring objective under audit.
Trap 3: Number of pull requests merged into the model-serving repository…
Pull request counts measure development activity, not changes in the statistical relationship the deployed model relies on. A quiet sprint does not mean the model is stable, and a busy one does not mean it has drifted, so this activity metric gives the auditor no evidence about concept drift in production.
- A
Total inference latency measured at the API gateway
Why it fails: Latency reflects infrastructure and serving performance, not whether the mapping from inputs to labels has changed. A model can serve quickly while silently degrading in accuracy, so latency monitoring, however useful operationally, does not indicate concept drift and should not be relied on for that purpose.
- B
Count of active user accounts authorized to call the prediction endpoint
Why it fails: The number of authorized accounts is an access-control and provisioning metric. It says nothing about whether the model's decision behaviour still matches the environment it was trained on, so it cannot serve as evidence of concept drift and is unrelated to the monitoring objective under audit.
- C
Population Stability Index comparing live feature distributions with the training baseline
Population Stability Index quantifies how far a live feature distribution has shifted from the training reference, which is a direct signal that the input space no longer matches what the model learned. Tracking it on a schedule lets the auditor confirm the team detects data drift before it degrades decisions, making it an appropriate ongoing monitoring indicator.
- D
Number of pull requests merged into the model-serving repository each sprint
Why it fails: Pull request counts measure development activity, not changes in the statistical relationship the deployed model relies on. A quiet sprint does not mean the model is stable, and a busy one does not mean it has drifted, so this activity metric gives the auditor no evidence about concept drift in production.
- E
Drift in the relationship between inputs and observed labels, such as a falling live accuracy against delayed ground truth
Concept drift is a change in the input-to-label relationship, so it can only be seen by comparing predictions with labels that arrive later. Monitoring live accuracy or another performance metric against delayed ground truth is the indicator that directly exposes concept drift, which distribution-only checks on features cannot reveal.