A single source of truth means every important piece of business information (customers, products, prices, jobs, sales, costs) has one agreed home, and every system, report and spreadsheet takes its copy from there. In plain English: one set of numbers everyone trusts. For most growing businesses it doesn't mean buying one big system. It means deciding where each piece of information lives, connecting the systems so it flows instead of being retyped, and building reports from those connected systems. This guide explains why numbers end up disagreeing and the practical steps to fix it.
Why your numbers disagree
Most businesses don't plan to have several versions of the truth. It happens gradually:
- New systems are added one at a time: accounts first, then a job or stock system, a CRM, payroll, maybe an online store. Each holds its own copy of customers, products or jobs.
- Spreadsheets fill the gaps: where systems don't connect, someone exports, copies and builds a spreadsheet. Then someone else builds a slightly different one.
- Information is retyped: every time it's typed again, there's a chance it's typed differently.
- Timing differs: one system is updated daily, another at month-end, a spreadsheet whenever someone remembers.
The result is familiar: sales and finance have different revenue figures, stock in the system doesn't match the shelf, and meetings start by arguing about whose numbers are right.
What "one set of numbers" looks like in practice
You know you're there when:
- each important type of information has one agreed home and an owner,
- other systems take their copy from that home automatically,
- reports draw on the connected systems and match the accounts,
- and nobody keeps a private spreadsheet because they don't trust the official numbers.
Step by step: getting there
1. Start with the arguments
List the figures people argue about or rebuild by hand. Revenue, job profitability, stock and debtors are common. Fix the one that matters most first.
2. Trace each figure to its source
For each figure, find where the information is first entered, where it's copied, and where the versions start to differ.
3. Agree one home for each piece of information
For example: customers live in the CRM, products and prices in the stock system, invoices and payments in the accounts. Give each an owner who's responsible for keeping it right.
4. Connect the systems
Make the other systems take their copy from the agreed home automatically, instead of being retyped. Where information has to be reconciled, have differences flagged automatically rather than found at month-end.
5. Build reports from the connected systems
Once the data flows, reports and dashboards can be built from it and refresh themselves, so nobody rebuilds them by hand.
6. Retire the risky spreadsheets
Move the spreadsheets that run part of the business into proper systems, or at least connect them, so key figures don't depend on one person's file.
Do you need one big system?
Usually not. Replacing everything with one system is expensive and disruptive, and businesses often end up with spreadsheets around the new system too. Connecting the systems you already have, with clear agreement on where each piece of information lives, gets most businesses to one set of numbers faster and with less risk.
When to get help
You can usually do steps 1 to 3 yourselves. Steps 4 to 6 involve connecting systems and building reporting, which is where outside help pays off, especially when several systems or entities are involved. See one set of numbers and when the problem is between your systems.
Frequently asked questions
What does single source of truth mean?
It means one trusted version of each important piece of business information, such as customers, products, jobs, sales and costs, that every system and report uses, instead of several copies that disagree.
What are data silos?
Information stuck in separate systems or spreadsheets that don't share it. They're the main reason figures disagree and reports have to be rebuilt by hand.
Can spreadsheets be part of a single source of truth?
They can be used for analysis, but they make a poor home for important information that several people update. Business-critical spreadsheets are usually better moved into a proper system or connected to one.
Where should we start?
With the figure that causes the most arguments or manual work. Fixing one area properly shows the way, and builds trust, for the rest.
If your team spends meetings arguing about whose numbers are right, book a free initial chat. We'll help you work out where the versions part ways and what it would take to fix it.