Abstract: Larger mailing lists with fewer returned mailings may be achieved by tracking the mailings, the reasons for their return and other information. By compiling this information, an intelligent suppression process may be achieved to reduce the number of returned mailings while maintaining a large mailing list. The process may determine when a mailing may not be valid so that mailings to invalid addresses may be avoided in the future. Also, the process may determine when a mailing is returned for reasons other than it being sent to an invalid address so that mailings to these addresses may be continued in the future. Databases created by this process also may be used for other purposes such as determining the ultimate value of a mailing list or data source, determining when a vendor is double charging, and building predictive deliverability models.