SCOTT DETROW, HOST:
Back in the 1960s, there was a heaping surplus of mail in the U.S. Post offices were struggling to keep up with deliveries. According to the Smithsonian's National Postal Museum, mail volume reached 63.7 billion pieces in 1960.
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UNIDENTIFIED JOURNALIST: The post office stands to be swamped, overwhelmed, drowned in a sea of mail. Where do we go from here?
DETROW: There was a simple solution, a new concept called the Zone Improvement Plan code. You know it as the ZIP code. It was introduced on July 1, 1963, 60 years ago today. NPR's Jessica Green has the story.
JESSICA GREEN, BYLINE: The Post Office Department, a forerunner for the U.S. Postal Service, had a saying in 1963 - mail moves the country, ZIP code moves the mail. With the help of new sorting machines, the five-digit ZIP codes pinpointed locations of addresses across the country and made mail sorting a whole lot faster. Nancy Pope was head curator of the Smithsonian's National Postal Museum. She spoke to NPR in 2013.
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NANCY POPE: It was really amazing because you had before people who were hand sorting. And hand sorting, even if you're really good at it, you're not going to do more than 60 letters a minute. But when they had the machine and could use the machine, they ended up sorting at 1,700 letters per minute.
GREEN: It was a brave new world in mail delivery. But Pope says memorizing a bunch of numbers was a tough sell to the American public back in the '60s.
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POPE: AT&T had just been rolling out area codes for people to use. And AT&T told the Post Office Department, you're going to need a lot of help because people hate area codes. And so here you have people who were feeling like they're being turned into numbers. But in the '60s, it was kind of scary for the American public.
GREEN: So the Post Office Department appointed a zip code spokesperson, someone who promoted ZIP codes in newspapers, magazines and on TV and radio ads. He was a crudely drawn cartoon mailman dressed in blue with big eyes and a wide smile who went by the name Mr. ZIP.
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UNIDENTIFIED PERSON: This is Mr. ZIP. He revolutionized the mail delivery system of the United States with his ZIP code.
GREEN: The Post Office Department even produced this film featuring a song about ZIP codes.
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UNIDENTIFIED SINGERS: (Singing) You know you've got to have a ZIP code. (Inaudible). And everything will be all right.
GREEN: Today, ZIP codes mean more than efficiency with postal delivery. ZIP codes are used to predict voting habits, access to health care and life expectancy. They also represent economic disparities and racial discrimination.
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JOSH LAUER: Initially, credit scoring was very closely tied to discrimination because they used variables such as ZIP code.
GREEN: This is Josh Lauer, an author and associate professor at the University of New Hampshire. He spoke to NPR's Throughline in May.
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LAUER: And ZIP code, of course, could be used as a proxy for race. So just having a variable like ZIP code in a credit score or a credit scoring algorithm could reproduce these kinds of discrimination.
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DOROTHY A BROWN: When the IRS said we don't know your race, it was never the truth.
GREEN: Dorothy A. Brown is a professor of law at Georgetown and a tax expert. She spoke to NPR's Code Switch in April.
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BROWN: You know what the IRS knows? Your name and your ZIP code. If you give me a ZIP code, I can tell you what the race of the person whose tax return I'm looking at is.
GREEN: There are over 41,000 ZIP codes across the U.S. Those numbers reflect the values of the people occupying them, and in some cases, represent social standing. What began as a mail sorting tool has become a thread that connects us and defines who we are. Transcript provided by NPR, Copyright NPR.
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