A system of record (SOR) is an ISRS (information storage and retrieval system) that is the authoritative source for a particular data element in a system containing multiple sources of the same element. To ensure data integrity, there must be one -- and only one -- system of record for a given piece of information.
When data exists on multiple computers as a result of editing or data processing, subtle differences often arise. Discrepancies can occur because of bugs, file format conversion idiosyncrasies, multiple edits by humans, or time frame changes such as calendar updates. For information that doesn't change, such as historical data, SOR provides a traceable source of the original data. For information subject to change, such as a bank account balance, the SOR provides the most current information.
According to data warehousing expert Bill Inmon, every system of record shares the following characteristics: it provides the most complete, most accurate and most timely data, it has the best structural conformance to the data model, it is nearest to the point of operational entry and it can be used to feed other systems.