Health and Medicine

Average Joint Contains Much Less Marijuana Than Previously Thought


How much marijuana can we truly find in an average joint?

Until now, there was never a consensus. The previous research that was conducted submitted that a single joint held between 0.3 to 0.75 grams of marijuana, with amounts as high as 1 gram been reported among some users. The baseline that The United States Office of National Drug Control Policy makes use of is 0.5 grams.

Greg Ridgeway, an associate professor of criminology and statistics at the University of Pennsylvania along with his colleague Beau Kilmer of the RAND Corporation, have come out with new estimates. According to their analysis one joint contains 0.32 grams (0.30g–0.35g) of marijuana on the average. They came out with this estimate by keying into the drug-pricing model information gotten from over 10,000 marijuana transactions in the course of 11 years and from over 40 communities.

Ridgeway said that it turns out to be a critical number in the estimation of the amount of marijuana that is being consumed nationally, the amount that the drug-trafficking organizations are investing in the market and the amount that the states might be expecting in revenue post-legalization.

Their analysis began with the viewing of the information that originated from the U.S. Justice Department’s Arrestee Drug Abuse Monitoring program. Using this jail-based initiative, interviewers didn’t just ask those imprisoned on drug-related charges alone, but all arrestees, about the use of the substance and market transactions.

The data that they used had information on 10,628 transactions that were associated with marijuana, which includes whether they were joints or loose marijuana that the buyer purchased, the place where the dealings took place and the amount that the person paid.

Ridgeway said a number of them will let you know about loose purchases, either in ounces or grams, not only that, but they will also give you a dollar amount. Some said they paid $20 when they bought 4 joints and if a joint costs them $5 so would 0.5 grams, which proved that prices (by weight) were more or less the same.

Of course, it’s not as simple as people think it is. The prices did not integrate any inflation that happened in the course of the decade that the data covered. Furthermore, the drug markets differ from a place to place; for instance, the farther away a sale of marijuana happens from the place it was grown, the more expensive it becomes, due to the shipping costs that will be added for the final market price, and some drug traders offer bulk discounts to buyers too.

The researchers had to turn to a drug-pricing model to account for all these factors. Another thing that Ridgeway said was that his colleague and him used economic model and dataset that’s been frequently used for about 30 years now to unravel price and weight in order for them to get the estimation of the average joint weight which all boils down to roughly 0.3 grams, a figure that is lesser than what they had initially thought.

The knowledge of this exact number could give the U.S. government a better understanding of the amount of marijuana that is trafficked from Mexico into the U.S., as well as the accurate size of the illegal marijuana market in the United States. Apart from these, it also gives the possibility of improving dialogue about the legalization of marijuana, both for places that have already taken the step and those still considering it.

Ridgeway said he doesn’t have any plans to continue down this line of research, but it fits perfectly into his overall interest, which has its questions focused on policing, public safety, causes and consequences of crime and the criminal justice system – information that could benefit policymakers at both the state and national level.

Findings were published in the journal of Drug and Alcohol Dependence.