Seven Tips to Stem Losses from Unaccounted Movers

4. Maintain source data. Customer supplied data is the most reliable, so make sure the current address is verified every time contact is made. NCOA matches are next in terms of reliability, then ACS, and finally third-party sources. Many mailers test third-party source changes through inexpensive, First class or endorsed postcard mailings in order to verify the address before applying it to their databases or using it on more expensive campaigns.