"Which number is right?" is a sign you don't have a single source of truth. When sales, marketing, and finance each have their own version of "revenue" or "customers," confusion follows. Here's how to fix it.

Define Your Key Metrics Once

Agree on definitions for the metrics that matter: revenue, customers, conversion, retention, etc. Write them down. Who counts as a customer? What counts as revenue? When is it recognised? One document, shared with everyone.

Choose One Place for Each Metric

Each key metric should live in one place. That might be a CRM, a database, a central spreadsheet, or a dashboard. The rule: if it's not in the source of truth, it's not official. No parallel spreadsheets with "the real numbers."

Connect Sources, Don't Copy

When data comes from multiple systems, connect them—don't copy-paste. Copies go stale and diverge. A connection—API, export, or integration—keeps the source of truth updated. Manual sync is a last resort.

Make It Accessible

A source of truth no one can access is useless. Put it where people need it: a shared dashboard, a report, or a spreadsheet with the right permissions. The goal is that everyone looks at the same numbers.

Maintain It

Data sources change. Definitions evolve. Assign someone to own the source of truth—to update definitions, fix broken connections, and answer questions. Without ownership, it will drift.

A single source of truth doesn't have to be perfect. It has to be consistent, accessible, and maintained. That's enough to improve decisions across the business.