Study: Marijuana Workplace Impairment Metrics Likely Flawed

New research has found bias and bad methodology behind many studies that allegedly prove cannabis workplace impairment can be dangerous.

Workplace drug testing has come under fire in the last few years as more states legalize cannabis. Blood tests, which claim to help employers find the best people, have instead become a way to eliminate cannabis users from job opportunities.

Nobody wants workplace injuries as a result of substance use. And we’re not advocating for workplace impairment. But we’re sure going to take a look at the methodology behind studying it. Science has devised fairly accurate tests to predict alcohol impairment, but we haven’t been able to do that with cannabis. We can determine if people are using cannabis, but there are no tests that show whether that use indicates actual impairment. This is important.  

Some companies in legal states and municipalities who have found it more difficult to hire non-users have responded by ending cannabis drug screenings for jobs. But employees can still be fired for using it, even outside the workplace. In a high-profile case in 2017, the Colorado Supreme Court found that Dish Network was within its right to fire Brandon Coats, an employee who used cannabis outside work with a state medical marijuana registration card. The high court said the company was justified because marijuana remains illegal federally. Other companies continue to draw the line, especially when it comes to jobs that require motorized equipment, including forklifts, power equipment, and vehicles.

Federal and state laws understandably prohibit impairment while operating heavy machinery. Occupational licensure and guidelines are designed to regulate bad behavior around dangerous equipment in the name of health and safety. But what is impairment when it comes to cannabis? And are some companies using flawed science to conclude that employees are impaired on the job? 

Employers use a number of studies to prove their point about workplace injuries. But a new report published in the journal “Substance Use and Abuse” took a hard look at those same studies—16 in all—that prove cannabis “dysfunction.” It concluded that those studies didn’t prove workplace danger at all. The tests actually show adults who use cannabis aren’t any more likely to experience injuries at work than those who don’t.

University of British Columbia researchers Wade Biasutti, Kurt Leffers and Russell Callaghan looked at every study used to prove cannabis use impairs working people and found that the evidence in those studies doesn’t support the conclusions. The researchers further suggest that many of the studies were flawed and showed bias in selection of variables, participants and measurements of exposure and outcomes.

Specifically, the team found that seven of the studies supported an association between cannabis use and occupational injury; one showed evidence that there was no association; and the other eight showed no evidence of any significant relation.

This kind of sloppiness is part and parcel with the Drug War, which has peddled lies about cannabis for far too long

Leland Rucker

Legalization advocacy group NORML said of the study, “Investigators determined that most of the existing literature on the subject suffers from poor research designs. Specifically, few studies ‘employed research designs that ensured that cannabis use preceded the occupational injury outcome.’” Other tests didn’t control for simple variables like alcohol or another drug use. This latest research reinforces a 2017 National Academy of Sciences, Engineering and Medicine review that found no evidence that cannabis use leads to occupational injuries.

We’re asking for studies like these to not fall to the wayside and relegated to the sidelines as a relic of the 50-year-old multi-billion-dollar War on Drugs. Public sentiment has continued to shift, but some politicians still resist legalization measures that might actually help solve workplace issues and get them elected given marijuana legalization’s growing popularity. 

As we hit a tipping point in America’s struggle to understand the nation’s civil unrest, it is critical that we re-evaluate the mistakes of the past, including flawed cannabis research and methodology. Only then can we pave the way for a progressive future.

Leland Rucker is a journalist who has been covering the cannabis industry culture since Amendment 64 legalized adult-use in Colorado, for Boulder Weekly, Sensi and now His full bio is here.

Leland Rucker is a journalist who has been covering the cannabis industry culture since Amendment 64 legalized adult-use in Colorado, for Boulder Weekly, Sensi and now His full bio is here.

More Articles

Subscribe To Our Newsletter

Join our mailing list to receive the latest news and updates from our team.

You have Successfully Subscribed!