Glossary

Single Source of Truth

A single source of truth (SSOT) is one authoritative, agreed place where a given piece of information lives, so everyone reads and updates the same version instead of keeping rival copies. It removes the "which spreadsheet is right?" problem, kills duplicate data, and means a decision is based on one set of facts rather than several conflicting ones.

A single source of truth (SSOT) is one authoritative, agreed place where a given piece of information lives, so that everyone reads from and writes to the same version instead of keeping rival copies in separate files, inboxes and heads. It answers the daily question "which version is right?" by making sure there is only ever one.

Why a single source of truth matters

A single source of truth matters because conflicting copies of the same information are a steady, invisible tax on a team. Atlassian describes the idea as aggregating data scattered across systems into a single authoritative location, so people stop wasting time reconciling versions and losing trust in their own numbers. When the project tracker, the finance sheet and someone's email each claim a different status, work is done twice and decisions are made on the stale copy.

How it relates to systemising and automation

A single source of truth is the precondition for safely automating anything, because automation built on contradictory data simply spreads the contradiction faster. The discipline shows up in how the best-run organisations document themselves: GitLab runs a well-known "handbook-first" culture where the handbook is the single source of truth for how the company works, updated in one place rather than re-explained in meetings. The same logic sits behind process mapping — a current-state map is a single source of truth for how the work flows, just as a RAG status is a single source of truth for how it's going.

This is also why teams that have outgrown their spreadsheets feel the pain first: a spreadsheet copied five ways stops being a source of truth and becomes five sources of doubt. The Control Standard treats the system as living in the information flows between steps, and an SSOT is how you keep those flows honest.

Frequently asked

What does single source of truth mean in simple terms?

It means there is exactly one official place to look up or change a given fact — a customer's address, a project's status, the current price list. Everyone references that one place, so they all see the same answer. Copies are either eliminated or made to pull from the source automatically rather than being maintained by hand.

Why is a single source of truth important?

Because conflicting copies of the same data quietly cause wrong decisions, rework and arguments about whose number is right. When five spreadsheets disagree, someone acts on the stale one. A single source of truth removes that risk and makes information trustworthy enough to automate around.

Is a single source of truth the same as a master data record?

They are closely related but not identical. Master data management is one technique for achieving a single source of truth for core business entities like customers and products. A single source of truth is the broader principle, which can also be met with a shared document, a database, or a system of record.

How do you create a single source of truth?

Pick one authoritative system or document for each type of information, migrate the scattered copies into it, and then stop the copies being maintained separately — either delete them or have them read from the source. The hard part is social, not technical: agreeing that this place, and only this place, is now official.

Term

Process Mapping

Process mapping is the practice of drawing a process as a step-by-step diagram — showing each task, decision, handoff and information flow from trigger to outcome. It makes invisible work visible, exposes where things stall, and creates a shared picture a team can agree on before they try to improve or automate anything.

Term

RAG Status

A RAG status reports the health of a project or task with a traffic-light colour: Red, Amber or Green. It is a fast way to communicate at a glance, but on its own it is a summary of someone's judgement, not evidence of control — a green light only means as much as the owner, dated next step and fallback sitting behind it.

Guide

Signs You've Outgrown Spreadsheets (and What to Replace Them With)

You've outgrown a spreadsheet when it stops calculating and starts running a process. The signs: "final_v7" version chaos, weekly manual consolidation, one person who understands it, no audit trail, silent broken formulas, and people overwriting each other's edits. Replace it with a shared database, an off-the-shelf SaaS tool, or a custom internal app.

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