When customers are using our address verification capabilities via a Web service API within their applications and Web sites, they often ask what the difference is between an "address validation" and a "delivery point validation."
The ability to determine both exists within our product offering, but there is often confusion concerning the difference between the two and where and why the distinctions are useful. So let me try to explain.
In the case of "address validation" and whether or not an address is "valid", this refers to the CASS-certification-related style of determining the validity of an address according to the United States Postal Service master database (typically employed to gain postal discounts). However, this particular database only contains ranges of valid addresses for a given zip+4 location rather than a listing of actual physical addresses.
In other words, if you are trying to validate an address of "500 Broad Street, Anywhere, USA 12345", the database will contain entries of the ranges street numbers of that street in that particular city, and if the address to be validated falls within that range of valid street numbers, an address will be considered valid. This is without consideration as to whether or not that specific address physically exists and mail can be delivered to it. There could be a "490" Broad Street, a "496", and then a "504", but no "500". However, because it falls within a valid range, it will be returned as "valid."
This is where "delivery point validation" comes in (also known as DPV). During the address validation process, if the DPV flag is set to Y (because it exists in the DPV database), then this means that this particular address does indeed physically exist, is a "delivery point" and mail can be delivered to it. This is a more granular indicator in cases where that is necessary.
Here is an example of the two approaches. In the first, "500 Broad Street" would be determined a valid address:
In the second, the DPV indicator for this particular address would be returned as "N" since the address does not exist within the delivery point database:
So while a CASS-certified style of address verification is useful and effective in a broad set of business cases, what this demonstrates is that in terms of saving postage on undeliverable addresses and address quality in general, the DPV indicator, with its database containing over 145 million verified delivery points in the USA and its territories, is a more effective means of determining the physical existence of a given address and whether or not mail can actually be delivered.
Using both together, which StrikeIron does within both its North American Address Verification and Contact Record Verification Suite offerings, is a great approach to better address quality within any system.