A study by Quest Diagnostics released earlier this month, the Quest Diagnositcs Drug Testing Index (DTI), reported that based on more than 10 million workplace drug tests, the number of workers who tested positive for marijuana is on a 5-year upward trajectory.

Overall, the research found that the number of positive marijuana urine tests increased by 4% in the general U.S. workforce and by nearly 8% in the safety-sensitive workforce, which includes pilots, nuclear power plant workers, truck, bus and rail drivers, and other workers who undergo required routine drug testing by the U.S. Department of Transportation.

In addition, the report found that the increase in positive marijuana tests was largest in states that have legalized recreational cannabis, particularly Nevada (43% increase), Massachusetts (14% increase), and California (11% increase). It’s important to note that the researchers stated the significant increases in positive drug tests in states where cannabis was recently legalized are similar to increases observed after other states, such as Colorado and Washington, passed legalization laws.

Putting the Data into Perspective

When the data from Quest Diagnostic’s study was originally presented at the Federal Transit Administration (FTA) Drug and Alcohol Program National Conference this month, the story was crafted to call attention to the skyrocketing use of marijuana (and other drugs) with the key message in the company’s press release saying, “Workforce drug positivity is at its highest rate in a decade.” However, the marijuana story doesn’t look quite as grim when you put the data into perspective. Consider the following data from the study:

Marijuana Positivity Rates for the General U.S. Workforce (Urine Tests)

• 2013: 2.1 %
• 2014: 2.4%
• 2015: 2.5%
• 2016: 2.5%
• 2017: 2.6%

Marijuana Positivity Rates for Federally-Mandated, Safety-Sensitive Workforce (Urine Tests)

• 2013: 0.67%
• 2014: 0.71%
• 2015: 0.71%
• 2016: 0.78%
• 2017: 0.84%

Marijuana Positivity Rates for the Combined U.S. Workforce (Urine Tests)

• 2013: 1.7 %
• 2014: 1.9%
• 2015: 1.9%
• 2016: 2.0%
• 2017: 2.1%

Yes, the data shows an upward trend in positive marijuana drug tests conducted by employers, but the overall increase is not quite as striking as you might think if you read the press release title but don’t look at the actual data.

It’s also important to consider that while marijuana use does typically rise after a state legalizes recreational marijuana, usage rates level out over time. It’s highly unlikely that a 43% increase in positive workforce marijuana tests in Nevada will be a sustained growth trend. In fact, there could even be a decline in coming years.

Does the Data Tell the Full Story?

It’s clear that the data does not tell the full story. Multiple studies in the last couple of years have reported different reasons for the increase in marijuana use and thus, an increase in positive workforce marijuana tests. A 2016 study by the CATO Institute revealed that marijuana legalization at the state level has had a minimal effect on marijuana use.

The CATO Institute’s researchers found that in states with recreational marijuana, usage was increasing for several years prior to legalization. After legalization, use rates deviated from the prior growth trend to a minor degree. The researchers found, “The data do not show dramatic changes in use rates corresponding to either the expansion of medical marijuana or legalization,” in Colorado, Washington State, or Oregon. In addition, researchers found that alcohol use followed a pattern similar to marijuana with a gradual upward trend in recent years.

Based on its observations, researchers from the CATO Institute determined, “Rising marijuana use may not be a consequence of legalization but a cause of it.” The researchers found a steady downward trend in the number of people who associate monthly marijuana use with high risk. This trend started before legalization of marijuana, which supports the theory that it was people’s opinions about marijuana that caused policies to change and use to increase. In other words, legalization was not the catalyst.

A 2017 study published by the Society for the Study of Addiction shared similar conclusions. Specifically, the researchers stated that while marijuana use is increasing in the United States, the cause is not the growing availability of medical and recreational marijuana across the country. The study authors wrote, “Marijuana policy liberalization over the past 20 years has certainly been associated with increased marijuana use; however, policy changes appeared to have occurred in response to changing attitudes within states.”

In fact, the study authors attributed the increased use of marijuana to a term used in psychology and social science, period effect, which refers to a change that occurs at a particular time that affects all people uniformly. In other words, environmental and societal factors have affected people of all ages and from all backgrounds over time making them feel more accepting of marijuana.

The study conclusion states, “The steep rise in marijuana use in the United States since 2005 occurred across the population and is attributable to general period effects not linked specifically to the liberalization of marijuana policies in some states.” Again, legalization is not the main cause of increased marijuana use (and increased positive worker drug tests). The primary catalyst is changing attitudes and perceptions.

The Question of Drug Test Effectiveness

Bottom-line, while the number of positive marijuana drug tests is increasing among American workers, legalization is not entirely to blame based on the data. Increased marijuana use is a trend that is unlikely to skyrocket in the future, but it won’t stop. Therefore, employers need a new solution that closes the gap between cannabis and employee drug testing.

Existing drug testing policies aren’t working since marijuana can be detected in the body for weeks after consumption and long after the effects have worn off. Today, employees lose their jobs when they test positive for marijuana even if they were simply exposed to it days or weeks before the test. For employees who don’t come to work feeling the effects of marijuana, the current drug testing methods don’t work.

In response, some employers like AutoNation, The Denver Post, and Excellence Health have stopped testing all employees or employees with non-safety sensitive positions for drugs. However, until testing methods change, the process remains broken.