A big un-fact checked myth about the high costs of legal weed on society has been circulating from the internet, news, and even the mouths of less than informed politicians.

The claim argues that, though legal cannabis generates billions of dollars in revenue, it actually costs a whole lot of money for states that legalize.

“In fact, taxpayers and communities have had to shoulder an estimated $4.50 in social costs for every $1 in revenue, according to researchers at the Centennial Institute,” wrote Kevin Sabet in a New York Post article.

Since the Post publication last month, the $4.50 figure has appeared all over the place. As High Times reports, the figure has been repeated by a slew of politicians and government agencies, including the U.S. Attorney for Oklahoma, a New Jersey mayor, an Illinois county health department, and, perhaps most troublingly, in an official report from the Office of National Drug Control Policy (ONDCP), an agency in the U.S. executive branch.

The ONDCP, it should be noted, also spent a chunk of last year asking for help from federal agencies in gathering “facts about the negative impacts of marijuana” (but not the positive ones).

The statistic has been roundly rebuked by multiple drug policy experts. The original “finding” came from the right-wing think tank the Centennial Institute and was popularized by Sabet, who heads the New York branch of Smart Approaches to Marijuana, perhaps the most fervent anti-cannabis advocacy group in the country right now.

The $4.50 figure was reached in part by finding the number of cannabis-related expulsions and dropouts from schools in Colorado and multiplying that by the estimated $334,716.12 it costs a state for a person to not get a high-school diploma. It does not, however, factor in the cost of penalizing and jailing persons charged and convicted of cannabis crimes, nor does it take into effect the costs of opioid use and abuse which legal cannabis offsets.

The statistic has been called “laughably bad” math by Reason and compared to the flat earth conspiracy by Michael Collins from the Drug Policy Alliance.

Photo via Flickr user 401(K) 2012