Does anybody know a plugin/addin tool to allow to detect duplicate
No, sorry.
Anyone has experience doing this before?
In this country, (AUS) mail is delivered to an 'address point'. To get
the cheapest mail rates, you identify the address point before giving
the mail to the post office. To verify an address, you run it against
a set of all the address points in Australia. This is a big job, and is
normally only done by a mail house.
To verify a particular persons address, you run it against a database
of known peoples addresses - for example, a telephone book, or
a listing of all known medical doctors. This also removes addresses
that it knows to be invalid. You can't normally buy those address lists,
you have to send your data for matching.
When I'm just doing data cleaning, I can't do either of those things,
but those are the only services available, so I have to fall back on
just doing it myself. That has always meant running selection queries
and then eye-balling the data: First you match on SSN (TFN), Telephone,
or medical record number. Then on Post Code and Suburb. Then on
everything else... until you've done this, you wouldn't believe the
incredible variety of true addresses, let alone the variations on a theme.
Out of a thousand address, you're sure to get 10 forwarding addresses,
and one that looks like this:
Ward 3/4, Janefield Training Centre, private bag 1, suburb, zip
Try fitting that into your normalised number/street/suburb table!
Then compare it to the delivery address:
Ward 314, Private road, Janefield Training Centre, suburb, zip2
-- and remember that the zip code for a private bag (which is like
a post office box, but sorted at the mail sorting centre) is different
from the zip code for street delivery. And the private road is
actually a very long driveway.
So I had some sympathy for my bank when they changed the
post code on my PO box address: I understood the kind of data
cleaning exercise which would lead to that mistake. Rather less
when the customer service rep told me that they Never Change
the Address without a direction from the customer. None at all
when they denied all responsibility in writing. Slight rage when
they sent me a letter asking if I was satisfied with their response.
Irritation when they ignored that as well...
(david)