What is schema violation?

Example: You ship a feature you're certain users will love. Product analytics show 4% adoption after three weeks. Your stomach drops. That drop is not a sign that you are wrong about everything — it is your schema ('I understand what users need') colliding with reality. The discomfort is a signal: your model of the user was inaccurate in a specific, discoverable way. If you defend the feature, you protect the schema and learn nothing. If you investigate the gap between your prediction and the outcome, you upgrade the model.

This concept is part of Schema Foundations in the How to Think curriculum.