Day 60 of 60 · AI-system specific

ML model & feature drift detection

Models decay silently as the world drifts away from training data. Without drift detection, the first to notice is Sales, looking at retention.

ProblemModel performance degrades silently as input distribution shifts away from training data.

How it works

Monitor input feature distributions, output distributions, and (where available) ground-truth performance. Alert on statistical drift. Trigger retraining or rollback.

What it catches

Distribution shift, label drift, concept drift, silent model decay. Without it, models degrade and only Sales notices when retention drops.

Tools

Evidently AI · OSS Arize · Hybrid WhyLabs · Hybrid Fiddler · SaaS

Verdict by project size

Small
Skip
Medium
Opt
Large
Rec
Extra-large
Must

Cost

Project size Setup Maint / mo Tool / mo CI / run
Small <10k LOC 1d 1h $0 ,
Medium 10–100k LOC 3d 5h $300 ,
Large 100k–1M LOC 15d 25h $3k ,
Extra-large >1M LOC 60d 120h $25k ,
Setup = engineer-days to first useful run · Maint = engineer-hours / month at steady state · Tool = out-of-pocket $ / month · CI = minutes added (or saved) per pipeline run

Lifecycle & ownership

When in lifecycle
Test Operate Observe
Per merge · Runs after merge to main; nightly heavy jobs.
Who owns it
ML / AI Engineer
Models, evals, drift, guardrails
Collaborates with: Developer, Security / AppSec

Reference implementations

Quick check

Without ML drift detection, model decay is typically discovered by…

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thinkbridge THE VALIDATION ATLAS DAY 60 OF 60 AI-SYSTEM SPECIFIC ML model & feature driftdetection Models decay silently as the world drifts away from trainingdata. Without drift detection, the first to notice is Sales, looking at retention. FIVE-MINUTE LESSON · ONE QUICK-CHECK QUESTION There’s a new way there
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