A National Deliverability Index (NDI) score indicates how accurately the address records in a mailing list match the latest address data maintained by the US Postal Service. Mailing lists are matched using automated Address Verification programs.
A National Deliverability Index (NDI) score indicates how accurately the address records in a mailing list match the latest address data maintained by the US Postal Service. Mailing lists are matched using automated Address Verification programs.