Data Entry Integrity

Techniques to ensure data entered into a system is both sensible and accurate.

Data Validation

Validation is an automatic computer check to ensure data is sensible and reasonable. It does not check if the data is true, only if it is allowed.

Range Check

Ensures data falls within a specified numerical range (e.g., Percentages between 0 and 100).

Type Check

Ensures the data is of the correct type (e.g., only numbers in a "Quantity" field).

Presence Check

Ensures that a required field has not been left blank.

Format Check

Ensures data follows a pre-set pattern (e.g., Date as DD/MM/YYYY).

Data Verification

Verification is a way of ensuring that the data entered matches the original source. This usually involves human intervention or double-checking.

  • Double Entry: Entering the data twice (e.g., "Confirm Password") to check for discrepancies.
  • Visual Check: The user manually compares the data on the screen with the source document.
  • Checksums: A mathematical value calculated from the data to verify it hasn't been corrupted during transmission.

Validation vs. Verification

A system can Validate that a date exists, but only Verification can confirm it is actually your birthday. High-integrity systems use both to prevent "Garbage In, Garbage Out."