# Single source of truth · Glossary
An agreed, authoritative location and definition for each important piece of data or metric, so that everyone uses the same figure for the same question.
[Glossary](/glossary) · Analytics engineering and analytics

# Single source of truth

     An agreed, authoritative location and definition for each important piece of data or metric, so that everyone uses the same figure for the same question. It is achieved through governance and design, not by putting all data in one system.

## Why it matters

     When departments report different numbers for the same measure, meetings are spent reconciling rather than deciding. A single source of truth reduces that friction and makes accountability clearer.

     In practice, different systems remain authoritative for different data. The goal is that each metric and entity has one agreed definition and owner, and that reports draw from certified sources.

## In practice

     For example, a UK housing developer might agree that completions are counted from the legal completion date in the sales system, certify that table in the warehouse, and retire the several spreadsheets that previously used exchange dates or handover dates.

## Where Rodan fits

     Rodan establishes certified metrics and data products in [Analytics and Intelligence](https://rodan.io/what-we-build/analytics-intelligence) work.

## Related terms

- [Semantic layer](/glossary#semantic-layer)

- [Master data management (MDM)](/glossary/master-data-management)

- [Data warehouse](/glossary/data-warehouse)

- [Data governance](/glossary/data-governance)

- [Analytics engineering](/glossary/analytics-engineering)

- [Entity resolution](/glossary/entity-resolution)

- [Self-service analytics](/glossary/self-service-analytics)
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