Thread by @propublica

1/ They’re being marketed as a way to stop school violence.

They listen to your kids’ voices.

They’re called aggression detectors.

But do they work?

Our reporters decided to test one of them out.

Here’s what they found. 👇👇👇

2/ Things that triggered the alarms:
- singing
- coughing
- playing Pictionary (see video👇)

- this YouTube clip of Gilbert Gottfried (“Is it hot in here, or am I crazy?”)

- and students cheering for pizza 🍕

5/ Something that didn't set off the “aggression detector”: a student’s ear-piercing screams.

6/ So what’s the deal?

When it comes to machine learning technology, people often have to rely on information a company provides.

Companies don’t tell the public much about how it works — we’re just expected to trust their judgment in building the algorithm.

7/ But even if the detector did work perfectly, some academics question whether we should allow it in schools in the first place. A school safety expert we spoke to warns that the detector and other devices like it increase student distrust and alienation.

8/ The company acknowledges the aggression detector is not perfect, but maintains that it's still a valuable early warning system.

9/ Regardless of the privacy concerns, tech like this will continue to contribute to the booming $2.7 billion education security market, according to one analyst.

So keep an eye out.

It may look like a fire alarm, but it does (and costs) quite a bit more.

10/ Don’t miss our investigations: propub.li/2LlXgwa

11/ And read the full story here: propub.li/2RBpaoV

...or on @AppleNews: propub.li/2Fzk9IS