Your PSI alerts fire every Monday. How do you decide if that is noise, seasonality, or a real incident?
PICTURE THIS: DATA SPLIT
Fit on train, tune on val, report on test once.
Simple meaning
I would compare against last Monday and a seasonal baseline, not only versus the training month.
WHY — Data Drift instead of guessing?
Why interviewers care about Data Drift:
people who only read docs from people who shipped.
and tied to MLOps work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1I would compare against
last Monday and a seasonal baseline, not only versus the training month.
- 2If delayed labels and
calibration are stable, I would retune the reference window or suppress known calendar effects.
- 3If a new traffic
source appears in slices, I would treat it as an incident and check pipelines and product launches.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
I would compare against last Monday and a seasonal baseline, not only versus the training month. If delayed labels and calibration are stable, I would retune the reference window or suppress known calendar effects.