As some one who used to deal in creating /designing / relational databases (after receiving from the local county,) for signature gathers (i.e. petitions) to make it easy to; if you will, go up & down the different street(s) and not miss any legal voters. Via the different voting precincts.
What I came across, is the double listed voters in the same precincts, but of course I was a piss-ant, and nobody listen.
Every town / city / urban area, etc., has what I'll call the street with 2 (two) names, and people receive and send U.S. Mail, using the different names!
Example: "Main Street" might also be known as say 1st (First avenue.) or just like in this example: 1st Avenue vs First Avenue.
So what you may say, well you better take a CLOSER LOOK, because I saw a lot of names that got ballots for what I'll call street(s) with 2 (two) names. And just sometimes you might be able to say: well the names just happen to be the same. But depending on where you live, every town / city / urban area, etc., may have the street(s) with 2 (two) names, but that ADDRESS, YES you know what I mean, that ADDRESS, is just 1 (one) of a kind, with both street name(s.)
The PO has databases which should show these address variations. My local PO is always open, only 2 blocks away and has an automated kiosk that will take my $ and generate addressed mailing labels at all hours of the night. Last time I mailed my sister a package it asked for 5 digit zip code, the house number and just the first number of her street and promptly popped up a list of the only two addresses with those values. One click and I had a mailable label. A database that can do that should be able to ID most of the duplicates. Granted, the government databases will have some errors so a user friendly error correction system providing some benefit of the doubt must be included so honest voters can at worst get and eventually validate a provisional ballot.