Single source of truth
Also known as: SSOT · system of record
Definition
An architectural principle that for any given piece of data — an employee record, an IBAN, a contract — exactly one system is treated as authoritative. All other systems consume from or feed into that one source.
Why it matters for HRIS ↔ payroll sync
Most HRIS-payroll pairs are run as informal dual masters: the HRIS holds the people record but the payroll system holds the IBAN and the tax class. That works until the two diverge — and then no one can tell which value is correct. Naming a single source of truth for each field, and using a sync tool to keep the others aligned, eliminates the "which spreadsheet is current" problem at its root.