This type of format definition is an error-tolerant algorithm that finds strings that match the provided text exactly, or strings that differ by one or two characters.

For example, a search for "Invoice" returns exact matches for "Invoice," but it can also return single error matches such as "Invoike." It can also return matches with two errors such as "Invoke." The confidence level decreases for each error.

Use this type of format definition to account for common typographical errors such as character interchange or misspellings. The confidence of a result is very sensitive to errors.