Data Drift Detection Fundamentals

Catch Production Data Drifting Away From Your Training Data With KS, PSI, and Chi-Squared Tests Before Accuracy Quietly Drops.

By Sandip Das · · 5 min read

Data Drift Detection Fundamentals
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Hey — It's Sandip Das 👋

In Day 39 we put a Great Expectations gate in front of the pipeline so broken batches never reach training. But data can pass every rule and still be wrong for your model: valid values, different world.

Today we learn to detect drift: compare production data against training data with statistical tests, and let Evidently AI tell us which features moved.

📚 Key Learnings

  • What data drift is and why valid data can still break a model
  • Covariate shift, label (prior) drift and concept drift, with examples
  • The three workhorse tests: KS, PSI and chi-squared, and when to use each
  • Running an Evidently drift report on reference vs production iris data
  • Hands-on: simulate drift, find the drifted features, fail on drift in a script

🧠 Learn here

Read the full article on learnxops.com.

Topics: 100 Days of MLOps, MLOps, ML, Monitoring