The most common typing errors are single digit errors and transposition errors. An additional digit is attached to the number in order to detect errors. This digit is called the check digit. It is commonly believe that mod-9 check digits is the best strategy to detect errors, but mod-9 check digits never detect transposition errors. In contrast, mod-7 check digits detect 93.87% of all transposition errors.
Contributors Eduardo Díaz Guerrero
( Topic last updated: 2008.01.30 04:24:00 PM )