Shared Check Authorization Network (SCAN) is a comprehensive database of bad check writers in the United States . The database is used by retailers in order to reduce the number of bad checks received. The data base of the present invention relates to a method for determining the presence of a particular accountholder.

Retailers using the SCAN system have at least one scanner in the store, and often one at every register, that is used to scan checks that are written. The scanner reads the account number and compares it with the database of checking account numbers for which bad checks have been written to any participating retailer and not repaid. If the account number matches one in the system, the retailer will be notified, and will not accept the check.

SCAN also operates a collection service on bad checks that are written.