Single Source of Truth Principle

The data architecture principle that every piece of critical information should have exactly one authoritative source, with all other references pointing back to it. When the same data exists in multiple places, discrepancies inevitably emerge: the CRM says one thing, the spreadsheet another, the presentation a third. Single source of truth eliminates reconciliation nightmares. Applied beyond databases: every organization needs a single authoritative answer for pricing, strategy, process, and policy—and everyone needs to know where it lives.

When to use it

When teams work from conflicting versions of the same information; when data reconciliation consumes significant effort; when decisions are delayed because no one knows which number is correct; when designing information architecture for growing teams.

How it can help

For every critical piece of information, ask: where is the single source of truth, and does everyone know? Common failures: pricing in multiple spreadsheets, strategy in conflicting documents, customer data split across systems. The fix: designate one authoritative source for each information type, make it accessible, keep it updated, and enforce the discipline that all references point to it. The cost of maintaining one source is always less than reconciling many.