Market Audits Combat Cannabis Misinformation

We demonstrate cannabis products whose contents and safety are mislabeled and we show how active monitoring through off-the-shelf testing and forensic data analysis can dispel this misinformation. We tested products off the shelves of dispensaries in the U.S. state of Massachusetts for their content of cannabinoids, microbial contaminants, and heavy metals. Our results showed that levels of cannabinoid compounds are systematically overlabeled, that flower with forbidden levels of microbial contaminants reaches consumers, and that papers of prerolled joints may contain heavy metals. We demonstrate how the analysis of aggregated test results can pinpoint manipulations of data by bad actors in the testing industry. We evaluated the statistical distributions of results in aggregated cannabinoid analyses from multiple testing labs in the states of Oregon, Washington, Maryland, and Michigan. Our results demonstrate a strategy for actively monitoring a market for cannabis to make consumers safer: using periodic testing of products off the shelf to probe overall consumer value, and forensic data analysis to identify bad actors in the cannabis testing industry.