New Penn Research Shows Average Joint Contains Much Less ...

Skip to Content Skip to Content News from University of Pennsylvania Penn Today example title
  • News Archive
  • Topics

    Topics

    Focus Areas

  • Arts & Humanities
  • Social Sciences
  • Business & Law
  • Natural Sciences
  • Technology
  • Health & Medicine
  • Campus & Community
  • Global
  • Featured

  • Artificial Intelligence
  • Climate Change
  • Communications
  • mRNA Research
  • Robotics
  • Schools

    Schools

    Our Schools

  • School of Arts & Sciences
  • Wharton School
  • Annenberg School for Communication
  • School of Dental Medicine
  • Stuart Weitzman School of Design
  • Graduate School of Education
  • School of Engineering and Applied Science
  • Penn Carey Law
  • Perelman School of Medicine
  • School of Nursing
  • School of Social Policy & Practice
  • School of Veterinary Medicine
  • Explore

    Explore

    Pages

  • Announcements
  • Events
  • Newsletters
  • Penn in the News
  • Research at Penn
  • Search Menu
  • News Archive
  • Topics

    Focus Areas

    Focus Areas

  • Arts & Humanities
  • Social Sciences
  • Business & Law
  • Natural Sciences
  • Technology
  • Health & Medicine
  • Campus & Community
  • Global
  • Featured

    Featured

  • Artificial Intelligence
  • Climate Change
  • Communications
  • mRNA Research
  • Robotics
  • Schools

    Our Schools

    Our Schools

  • School of Arts & Sciences
  • Wharton School
  • Annenberg School for Communication
  • School of Dental Medicine
  • Stuart Weitzman School of Design
  • Graduate School of Education
  • School of Engineering and Applied Science
  • Penn Carey Law
  • Perelman School of Medicine
  • School of Nursing
  • School of Social Policy & Practice
  • School of Veterinary Medicine
  • Explore

    Pages

    Pages

  • Announcements
  • Events
  • Newsletters
  • Penn in the News
  • Research at Penn
  • News from University of Pennsylvania Search Search Try Advanced Search

    How much marijuana does the average joint contain?

    “It seems like an odd question but major policy questions depend on the answer,” said Greg Ridgeway, an associate professor of criminology and statistics at the University of Pennsylvania.

    Until now, there’s been no consensus. Previous research suggested a single joint held anywhere from 0.3 to 0.75 grams of cannabis, with some users reporting amounts as high as 1 gram. The United States Office of National Drug Control Policy used 0.5 grams as its baseline.

    Now Ridgeway and colleague Beau Kilmer of the RAND Corporation have a new answer. According to their analysis, on average, a single joint contains 0.32 grams of marijuana. They obtained this estimate by plugging into a drug-pricing model information from more than 10,000 marijuana transactions during 11 years and from more than 40 communities.

    “It turns out to be a critical number in estimating how much marijuana is being consumed [nationwide], how much drug-trafficking organizations are putting on the market and how much states might expect in revenue post-legalization,” Ridgeway said.

    He and Kilmer published their finding in the August issue of Drug and Alcohol Dependence.

    They started their analysis by looking at information from the U.S. Justice Department’s Arrestee Drug Abuse Monitoring program. Through this jail-based initiative, interviewers ask all arrestees, not just those imprisoned on drug-related charges, about substance use and market transactions.

    “The data had information on 10,628 transactions related to marijuana,” Ridgeway said, including whether the purchaser bought joints or loose marijuana, where the interactions happened and how much the person paid.

    “Some will tell you about loose purchases, in grams or ounces, and give you a dollar amount. Other people will say, ‘I bought four joints and paid $20,’” he said. “If I paid $5 for a joint and you paid $5 for 0.5 grams, that gives me some information. If they’re the same price, they must be roughly the same weight.”

    Of course, it’s not quite that simple. The prices don’t incorporate any inflation that occurred during the decade the data cover. Also, different places have different drug markets; for example, Ridgeway said marijuana is more expensive the farther away a sale happens from where it was grown, due to added shipping costs. And some drug sellers offer bulk discounts.

    To account for these factors, the researchers turned to a drug-pricing model. “My colleague and I used this dataset and an economic model that’s been used for about 30 years now to untangle weight and price, to estimate the average joint weight,” Ridgeway said. “That all boils down to about 0.3 grams, which is much less than previously thought.”

    Knowing this precise number could help the U.S. government better understand how much marijuana is trafficked from Mexico, as well as the size of the illicit marijuana market. It also has the potential to improve dialogue about legalization of the substance, both for places considering it and those that have already taken that step.

    Though Ridgeway said he doesn’t have plans to continue down this line of research, it fits into his overall interest, which focuses on questions of “public safety, policing, the criminal justice system and causes and consequences of crime,” he said.

    “I’m a statistician,” he added. “I think about statistical models and data analysis. I find datasets to answer difficult questions.” Now, one more has its answer, information that could benefit policymakers at both the state and national level.

    No external sources funded this research.

    Share this article

    Credits

  • Writers

    Michele W. Berger

  • More from

  • School of Arts & Sciences
  • An inside look at the history of television
    Handwritten notes and paper relics from TV shows in the past.

    nocred

    • Arts & Humanities

    An inside look at the history of television

    Materials in the Annenberg School for Communication Library Archives include thousands of TV scripts, the first issue of TV Guide, and interviews about the early days of HBO—which help to chronicle TV’s 100-year story. Centering joy in AI development and implementation
    Desmond Patton seated at his desk.

    nocred

    • Social Sciences

    Centering joy in AI development and implementation

    PIK Professor Desmond Upton Patton—of Annenberg and SP2—and collaborators introduce a joy-informed framework designed to initiate conversations among engineers, designers, and researchers. Why are icy surfaces slippery?
    An icy bench in a city.

    Despite the commonality of water and ice, says Penn physicist Robert Carpick, their physical properties are remarkably unique.

    (Image: mustafahacalaki via Getty Images)

    • Natural Sciences

    Why are icy surfaces slippery?

    Winter Storm Fern brought icy and snowy conditions to the Northeast and other parts of the country over the weekend. Penn Today asks physicist Robert Carpick about the unique properties of ice, the science of curling, and how close we are to ‘nonslip’ ice. Penn receives national distinction for community engagement
    High school students in a science class.

    Organizations like Penn’s Netter Center for Community Partnerships foster collaborations between Penn and public schools in the West Philadelphia community.

    nocred

    • Campus & Community

    Penn receives national distinction for community engagement

    The recognition by the American Council on Education and Carnegie Foundation for the Advancement of Teaching acknowledges Penn’s long-standing commitment to community-engaged scholarship and partnerships in West Philadelphia and beyond.

    Tag » How Much Weed In A Joint