The AVS (Address Verification Service) can return 4 possible responses - the AVS_DECODE_VALUE will be a number, 1-4, depending on how close of a match the billing address was to the bank's information:

1. Exact match - The street address and ZIP code the user provided with the card number exactly match what the issuing bank has on record
2. Street address match - The street address the user provided with the card number matches what the issuing bank has on record. The ZIP code did not match
3. ZIP code match - The ZIP code the user provided with the card number matches what the issuing bank has on record. The street address did not match.
4. No match - None of the billing information the user provided with the card number matches what the issuing bank has on record.

The other factor is about Street and Zip verification. It works like this:
Either Yes (Y), No (N), or null/no data
And
Street Verification (left letter) and Zip Verification (Right Letter)

YY - This means that both the Street and Zip are correct
NN - This means both are wrong
YN - This is Street is correct, Zip is not
NY - Street is wrong, Zip is Correct
XX - All data is wrong or missing
XY - Street is wrong or missing, Zip is correct
YX - Street is correct, Zip is wrong or missing
XN - Street is wrong or missing, Zip is wrong
NX - Street is wrong, and Zip is missing or incorrect

Depending on how the data is entered, it will either meet these requirements or it will fail, depending on your local settings.