A single source of truth is the principle that each fact about the business — this month’s revenue, the customer count, the margin on a product — has one authoritative place it comes from and one agreed way of calculating it. Every dashboard, report, spreadsheet and answer draws from that place and that definition, so two people asking the same question get the same number.
The absence of one is the most familiar reporting problem there is. Sales says the quarter closed at 4.1M; finance says 3.8M; both are right by their own definitions and the meeting spends twenty minutes on reconciliation instead of decisions. A retailer with three spreadsheets of store targets will find that they disagree. A single source of truth does not require a single system; it requires that the metric be defined once and that everything else refer to that definition.
The common misreading is that it means copying everything into one big database. It can, but the more practical version is agreement: one definition per metric, one owner, one place where it is computed, and every report reusing it rather than re-deriving it. Rule of thumb — if a number can be produced two ways inside your company, sooner or later it will be, and the two will differ.
In Klayara, metrics are defined once as calculated fields and reused by every dashboard, scheduled report and AI answer, with permissions attached to the data rather than to each page, so the number stays the same wherever it appears. See formulas and why teams choose Klayara.