On Fourth Amendment Privacy: Everybody’s Wrong

Posted by Jim Harper

Everybody’s wrong. That’s sort of the message I was putting out when I wrote my 2008 American University Law Review article entitled “Reforming Fourth Amendment Privacy Doctrine.”

A lot of people have poured a lot of effort into the “reasonable expectation of privacy” formulation Justice Harlan wrote about in his concurrence to the 1967 decision in U.S. v. Katz. But the Fourth Amendment isn’t about people’s expectations or the reasonableness of their expectations. It’s about whether, as a factual matter, they have concealed information from others—and whether the government is being reasonable in trying to discover that information.

The upshot of the “reasonable expectation of privacy” formulation is that the government can argue—straight-faced—that Americans don’t have a Fourth Amendment interest in their locations throughout the day and night because data revealing it is produced by their mobile phones’ interactions with telecommunications providers, and the telecom companies have that data.

I sat down with podcaster extraordinaire Caleb Brown the other day to talk about all this. He titled our conversation provocatively: “Should the Government Own Your GPS Location?“

600 Billion Data Points Per Day? It’s Time to Restore the Fourth Amendment

Posted by Jim Harper

Jeff Jonas has published an important post: “Your Movements Speak for Themselves: Space-Time Travel Data is Analytic Super-Food!”

More than you probably realize, your mobile device is a digital sensor, creating records of your whereabouts and movements:

Mobile devices in America are generating something like 600 billion geo-spatially tagged transactions per day. Every call, text message, email and data transfer handled by your mobile device creates a transaction with your space-time coordinate (to roughly 60 meters accuracy if there are three cell towers in range), whether you have GPS or not. Got a Blackberry? Every few minutes, it sends a heartbeat, creating a transaction whether you are using the phone or not. If the device is GPS-enabled and you’re using a location-based service your location is accurate to somewhere between 10 and 30 meters. Using Wi-Fi? It is accurate below 10 meters.

The process of deploying this data to markedly improve our lives is underway. A friend of Jonas’ says that space-time travel data used to reveal traffic tie-ups shaves two to four hours off his commute each week. When it is put to full use, “the world we live in will fundamentally change. Organizations and citizens alike will operate with substantially more efficiency. There will be less carbon emissions, increased longevity, and fewer deaths.”

This progress is not without cost:
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