The U.S. spends well over $100 billion each year for public safety, but we have remarkably little idea whether that money is well spent, New York University law Prof. Barry Friedman writes in the Washington Post.. It’s possible that any given policing tactic or technology, from Tasers to facial-recognition systems to body cameras, is either a fine or poor idea. We really don’t have much sense of which tactics and tools work, or whether they are worth the cost, Friedman maintains, adding, “We don’t know how much money we may be wasting, or whether we are compromising civil liberties, or harming people or property, without good reason.” As the Vera Institute of Justice has noted, cost-benefit analysis has not been widely taught or used in criminal justice.
Take ShotSpotter, a technology that uses sound waves to pinpoint where a gun has been fired. The product is marketed as allowing police to know about gunshots and respond quickly. Washington, D.C., spent $3.5 million on the system, but city doesn’t track arrests made as a result of ShotSpotter alerts. Another example is automatic license plate readers: fixed cameras, or cameras installed on police cars, that capture and digitize images of license plates. The technology was sold as a way to reduce car theft. With auto theft declining anyway, and at $10,000 or more for each mobile unit and $100,000 per fixed unit, it is hard to justify the cost. If police are looking for a van with a certain plate number, stored records may indicate where that van travels frequently or even where it parks. Success stories tend to rely on randomness: A police car happened to drive by the van at some point and dumped that data into the system. The benefits of what is basically random enforcement are likely to be small.