Missing data and zero demand

A forecast is not a promise; it is an input to a choice. This primer uses missing data and zero demand to make that distinction concrete.

Practitioner lens

For missing data and zero demand, inspect the history for stockouts, promotions, calendar changes and missing periods. Observed sales can differ from the demand customers actually wanted.

First experiment

Keep a time-based holdout. Do not shuffle observations when future periods must be predicted from the past.

This is an original educational brief. It is a starting point for discussion, not a claim that one technique fits every supply chain.