Dawn Choo on YouTube · Open on YouTube
Analytics engineering, data quality and governance · Proficient · Lesson 68 of 99 · 9 min video, then about 2 hours of practice
One definition of every metric: semantic layers and metric governance
After this you can explain what a semantic layer is, define metrics once in code, and resolve the 'why do these two dashboards disagree?' problem at its root.
Why it matters
When finance, marketing and product each calculate 'active customers' slightly differently, meetings turn into arguments about numbers instead of decisions. A semantic layer defines each metric once (in dbt's semantic layer, LookML, or a BI tool's model) and every tool reads the same definition. Even without the tooling, the practice of a written, owned, versioned metric definition is what matters.
How to use this resource
A clear nine-minute explanation of what a semantic layer is and the problem it solves, from August 2026.
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