Take a walk around Chicago or Boston or New York or Denver or San Diego and look up at the street corners.

Depending on the neighborhood you might see a little white box.

The devices are on top of buildings and also utility poles and other structures.

That's Jim Daly. He's the investigations editor at Southside Weekly, a community newspaper in Chicago.

And there's sort of oblong white boxes that look like the sort of thing that could pick up sound.

They look like they could pick up sound because they

do pick up sound. Jim's describing a device called a shot spotter. The way that it works

is the microphones detect loud noises that then computer

algorithms determine our gunshots. Then a human technician reviews it to

confirm that it's a gunshot or not. human technician

or not,

and then the technician, if they confirm it,

alerts the local police department

to the location of the shooting.

Jim says there are up to 3,000 of these sensors across Chicago.

More than half of the city's police districts use them.

It's in districts primarily that are on the south and west sides of Chicago,

which because Chicago is a very segregated city,

are disproportionately black and brown communities.

In theory, ShotSpotter keeps communities safe by quickly drawing police to the location of gunfire.

But in practice, it's not so simple.

ShotSpotter does not lead to a reduction in gun violence in our communities.

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