WP Issues CRM attempts to match incoming data to existing constituents
to avoid creating duplicates.  For unmatched constituents, all categories of incoming data will always be added, but, depending on the interface data source, you may want to set different policies on how incoming data will be applied
for matched constituents.  Note that constituent matching is attempted using field combinations in this order: (1) first name and email, (2) email alone, (3) first name, last name, street_address, (4)
first 5 letters of each of first name, full last name, street_address, (5) first name, last name, dob, (6) first name, last name, zip.