A data scientist is monitoring a deployed image classification model. Which TWO actions are best practices for detecting model drift? (Choose 2.)
A holdout test set provides labelled ground truth, letting the team measure accuracy decay against known-correct outputs over time. This detects concept drift that unlabelled input monitoring alone cannot confirm, satisfying the requirement to identify genuine performance degradation.
Why this answer
Option C is correct because periodically scoring the model against a fixed holdout test set gives a direct, repeatable measurement of accuracy degradation, which is the core signal of model drift. Option E is correct because tracking the distribution of input features over time (e.g., via histograms or statistical tests like KL divergence or PSI) detects data drift, which typically precedes and causes model drift. Option A is not a detection practice but a remediation action, and retraining blindly on a schedule does not identify drift.
Option B is a modeling change that may affect generalization but does nothing to detect drift in a deployed model. Option D is weaker than C and E because average prediction confidence can shift for reasons unrelated to drift and is not a reliable standalone drift indicator.
Exam trap
CompTIA often tests the distinction between detection and remediation actions, so candidates mistakenly choose retraining (Option A) as a detection method when it is actually a corrective action.