Routines in a data entry routine that test the input for correct and reasonable conditions, such as account numbers falling within a range, numeric data being all digits, dates having a valid month, day and year, etc. Checking the spelling of proper names, if possible, can also be part of validity checking. See validate
for a comparison of "validate" and "verify."
Errors Can Be Critical
It may seem like a dull part of the IT world, but data entry validation can be a very critical issue when there is insufficient validity checking of the input. In late 2001, a Japanese stockbroker erroneously placed a sell order for 610,000 shares of stock at 16 yen, when it should have been for 16 shares at 610,000 yen. Even though the error was caught two minutes after the order was placed, the broker's liability was estimated to be up to $100 million. See fat finger check