Welcome to more or less on the BBC World Service.

I'm Charlotte.

And I'm Simon Mabin.

This week, when maths can get you locked up. If you've seen or heard about the hit Netflix documentary series Making a Murderer, You'll know that the US state of

Wisconsin has had its problems with delivering fair justice. And now there's

another Wisconsin case that's been raising questions about how the US justice

system works. Two people are arrested in connection to a drive-by shooting on the

north side. It happened at about 2.15 this morning at a house on the 2,200 block.

In the early hours of Monday the 11th of February 2013,

two shots were fired at a house and lacrosse,

a small city in Wisconsin. A witness said the shots came from a car which police

tracked down and chased through the streets of lacrosse until the car ended up in

a snowbank. The two people inside ran off on foot but were found and arrested.

One of them was Eric Loomis, who admitted to driving the car but denied involvement in the shooting.

In court, he was sentenced to six years in prison.

And this is where the maths comes in.

In deciding to lock Loomis up,

the court noted that he had been identified as

an individual who is at high risk to the community

by something called the Compass Assessment. So what's one of those?

Compass is basically a questionnaire that is given to criminals when they're arrested. Julia Angwin is a

journalist at ProPublica, which is an independent investigative journalism

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