Data verification is the process of confirming that data is accurate and faithful to its source, that it was collected, transferred, or stored without being altered or corrupted. It answers a different question from validation: is this data actually correct, not just well-formed? Common methods include checksums, double entry, cross-checking against the source, and round-trip verification.
Verification matters most where accuracy is critical: data migration, backup and recovery, scientific records, and financial data. Together with validation, which checks that data follows defined rules, verification forms the two pillars of a data quality pipeline. For AI, verification also underpins traceability, confirming that the data behind a result is the data you think it is.