AVS or Address Verification System is a payment processing system comparison of the numerical portions of billing and shipping addresses with the addresses on file at the credit card-issuing bank. A single-digit code is returned that represents a match, a partial match, or a number of errors or alerts. The original concept contemplated that the transaction could then be subsequently approved, declined or set aside for manual review. AVS is one of only a few metrics provided to merchants by the issuing banks to assist in the merchants’ risk assessment, but AVS responses are also one of the biggest reasons legitimate orders are declined.