You build a semantic layer with governed metric definitions. Six months later teams are still writing their own SQL. Why, and what do you do?

What the interviewer is testing

Whether you understand that a governance layer succeeds on usability, not on authority.

The likely reasons

It is slower or more limited than direct SQL. If the layer cannot express a filter someone needs, or adds latency, people go around it. Analysts are solving a problem today.

It does not cover their metrics. The layer defines the top twenty; the analyst needs the twenty-first, and there is no fast path to add it — so they define it themselves, which is exactly the divergence the layer was built to prevent.

Direct access was never removed. If the underlying tables remain queryable with no friction, the layer is optional, and optional governance is not governance.

Their tool does not integrate with it. A layer that only works through one BI tool loses everyone using notebooks.

What to do

Fix the contribution path first. Adding a metric must be self-service with review — a pull request that ships in a day, not a request that waits for a quarter. This is usually the binding constraint, and fixing it converts the layer from an obstacle into a service.

Make it the fastest path: pre-aggregation and caching behind the layer, so querying through it is quicker than querying raw tables. Then adoption needs no argument.

Ensure it serves every consumer — BI, notebooks, applications — through an API, not just one tool.

Then narrow direct access to the raw tables, keeping it available for genuine exploration with a clear expectation that anything reported must come through the layer.

What a strong answer adds

Measuring the actual harm to make the case: find the metrics where independent definitions currently disagree and quantify the divergence. "Revenue differs by 4% between these two dashboards" is a concrete argument; "we need consistent definitions" is not.

Common weak answers

Mandating the layer without fixing the contribution path. Removing direct access first, which generates hostility and shadow extracts.