After a trade show,
the client would have 100+ names and addresses of potential government
customers. First handwritten and then typed into a spreadsheet,
the results needed to be verified before being uploaded to the CRM
database. For-fee services could be used, as could the US Postal
Services lookup API --- but the first would be too expensive for small
counts and the second is limited by terms- of-use, user account, and
number of searches.
- Need an efficient,
free, "good enough" method of address verification.
- The few
unverifiable addresses could be individually searched using the US
Postal Service website's lookup or by web searches.
My solution would
therefore need to address three areas:
The US Census
Bureau website has a no-cost feature that lets you look-up an address
to obtain information on its Census geography: census block,
census tract, county and more. In doing so, it verifies that the
address actually exists. I therefore automated the search of the
trade show addresses using this feature. The Census data was
reliable because the Census tracts individual homes and offices.
Although the Census is performed only every 10 years, there are
regular updates of address information as the Bureau makes estimates
and prepares for the next decennial Census. Post office boxes,
however, are not tracked and will therefore always be unverifiable
with this method.
Since the time of
my automated solution, the US Census Bureau has created a batch lookup
feature. You can now search 1,000 addresses at a time with no
and results of that new method are the same as my original solution:
Names are not used in the
search, so anonymity is preserved.
"No match" is
returned if unverifiable. Matches are noted as beings
Match/Exact, Match/Non-Exact (usually due to abbreviations), and
"Tie." Ties occur if you pass an address for an
apartment building but omit the apartment number. It is
still a match, but identifies a problem.
You can pass street addresses
with only a ZIP code and get the city and state returned. If
you have city and state without a ZIP code, ZIP code will be
As an added bonus, you also
get the county of the address as well as its census block and
census tract (useful for applying demographics to an address).
As mentioned, the
new Census Bureau bulk search feature has now made my automated solution
obsolete. In a recent test using 1,000 actual residential
addresses, the feature was able to verify all but 202 --- 39 of which
were post office boxes or blank addresses (which are always
unidentifiable). Omitting these obvious exceptions, the Census
Bureau bulk lookup had an 83% match rate at no cost.
If this were applied to very large customer databases, there could be a
significant cost savings in using for-fee address correction services.
To learn how the
Bureau's new feature works, click
the image below.