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 above the Block number. 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 a Column Number. In that circumstance, find the Column number in the form to locate the error. Data fields that are prepopulated may only be identified with a Column number as shown in Column #1 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 and correspond to the paper version of the performance measures. If you print the performance measures or received paper copies, the data fields are identified with a Block number. The Block numbers here in the EHB are the same as what appears in the paper copies of the performance measures. Nearly all fields where you enter data will be identified with a Block number.