There are two (2) types of data entry field identifiers. Each data entry field in a performance measure is identified with both types of numbers when the measure appears like the example in the above Figure.  

1. Column Numbers: The first is a column number. It is contained in parentheses below the name of the column. Column numbers are unique to the field in a particular form and are used to identify error messages. If you receive an error message, it will refer to the row that contains the error and the column number or numbers where there is an issue. In that circumstance, find the row and review the data in the identified column number to locate and fix the error. Data fields may only be identified with a column number as shown in Column #1 in the above Figure; others may have a column number and a block number as shown in Column #8 in the above figure.
2. Block Numbers: The second type of identifier is a block number. Block numbers are also unique to a data entry field. Some, but not all, fields where you enter data will be identified with a Block number.