Which data quality check helps identify incorrect formats in identifiers such as customer IDs?

• A. Outliers
• B. Validation
• C. Redundancy
• D. Completeness

Answer: (B)

Validation checks enforce that identifiers follow a defined format, such as a specific length, allowed characters, and separators. By applying these format rules—often via patterns or constraints—you can catch values that don’t conform to the expected ID structure, like an ID that should be eight digits or follow a particular alphanumeric pattern. This prevents misformatted IDs from slipping into analyses or downstream processes. Outliers look for values that are unusually large or small, not whether the value conforms to a prescribed format. Redundancy flags duplicates, and completeness checks ensure fields aren’t empty, but neither specifically screens for format violations.