This field pulls either the provider's tax ID number or social security number, depending on which is used from the Providers window, Provider IDs grid, TID/SSN column. Note: when creating an entry on the Provider IDs grid, you can select whether to use a tax ID or social security number or to pull one of those values from the Practice IDs grid instead. If you set up a rule to pull the value from the Practice IDs grid, and not the Provider IDs grid, the application will pull the value from the Practice grid. The application selects the correct entry from the grid, if multiple entries are present, via the rules engine selection process. For more information on rules entry/row selection see, Assigning Rules