Business intelligence2 min read
One definition per metric: why your dashboards disagree
When two reports show different revenue for the same month, the problem is rarely the maths. It is that the business never agreed what the number means.
Written by The metadatum team
Every growing organisation reaches the meeting where two people bring two different numbers for the same thing. Revenue, active customers, on-time delivery. Both reports are "right", because each calculates the figure its own way. The meeting turns into a debate about the data instead of a decision.
Where the differences come from
- Different filters. One report excludes refunds, another doesn't. One counts trial users, another only paying ones.
- Different timing. Orders counted when placed in one place and when invoiced in another.
- Different sources. Finance reads from the ledger, sales from the CRM, and the two never quite reconcile.
- Logic copied by hand. The same calculation rebuilt in five dashboards, each drifting a little as people fix things locally.
A semantic layer: define it once
A semantic layer is a single place where each metric is defined, in code, with its filters, timing and source. Every dashboard, spreadsheet and AI assistant reads the metric from there instead of recalculating it.
| Without one | With one |
|---|---|
| Each report computes revenue its own way | Revenue is defined once and reused |
| Fixes are made in one dashboard at a time | A fix in the definition reaches every report |
| Nobody knows which number is official | The definition is the official number |
Getting started
- Pick the ten metrics leadership argues about most. Start there, not with everything.
- Agree the definition in writing, with the people who own each number, before writing any code.
- Encode it once in the semantic layer, with tests that check known results.
- Point the most-used dashboards at it and retire the copies.
The goal isn't a perfect catalogue. It's that the next time a number is questioned, the answer is a definition everyone already agreed, not another spreadsheet.
