Weed testing labs are fudging data. What’s the solution?

As more states move to legalize marijuana, they’ll be confronted with a problem some consumers know all too well — corrupt labs inflating THC content to make a buck.

THC content is one of the primary ways consumers choose which products to buy. But a growing number of laboratories have been caught fudging the numbers.

These corrupt practices can do a number on peoples’ wallets. In California, pot with a THC content between 7 and 14% sells for $5.31 per gram on average. Pot with a THC content over 21% sells for more than $11 per gram.

False percentages can affect taxes too. New York, for instance, plans to tax cannabis based on its percentage of tetrahydrocannabinol.

Lab corruption is widespread because the market ends up rewarding the labs that are willing to give them better numbers. And it’s easy to pull off due to lax regulation. That’s a problem that needs fixing, experts say.

What’s the solution? Open data, says Washington data scientist Jim MacRae. His state made testing data available six years ago. Within three months, MacRae was able to flag suspicious results to authorities.

“Those data should be available to journalists, to interested data scientists like myself, and social sciences the world over would be fascinated by this shit,” he told FiveThirtyEight.

Read more about the scourge of fraudulent testing labs here.