In the Raiser's Edge 7.91 Patch 29 and below:

  1. Open Config > Business Rules > Duplicates
  2. Under Individual and/or Organizations add the field Address under Field Name and the length of characters to check
    If address is the only duplicate field to be checked, remove all other duplicate criteria
For more information on setting up duplicate criteria, please see BB1495

In The Raiser's Edge 7.92 and above:
Starting in RE 7.92, there is a Blackbaud defined algorithm which will weight and intelligently surface the best, most logical results based on the search criteria entered. The algorithm considers the following data fields: name, middle initial, suffix, address, phone number and email. This algorithm is hard-coded and is used by default within the database. The duplicate fields listed above are no longer present in version 7.92.
Note: For more information on managing duplicate records in version 7.92, see How to find and prevent duplicate records.