Tracking the illicit Cannabis Market during the closed Cannabis Supply Chain Experiment in Netherlands using an online Crowdsourcing Approach

Friday, 25 November, 2022 - 13:20 to 14:50


Background: Planned for late 2022, the Dutch government has decided to conduct an experiment with the legal supply of cannabis to coffeeshops in a closed supply chain in ten cities in the Netherlands. The aim of this experiment is to test the feasibility of regulating a quality-controlled supply of cannabis to coffeeshops and to study the effects of a regulated supply chain on crime, safety, public nuisance, and public health. A consortium of three institutes (Trimbos Institute, RAND Europe and Breuer&Intraval) is commissioned to monitor the results and evaluate the effects of this experiment. In order to track the developments on the illicit cannabis market during a baseline phase and after launch of the experiment, researchers collected consumer data about cannabis transactions outside the coffeeshop using an online crowdsourcing approach.

Methods: In addition to cities in the intervention group, the researchers selected a control group of cities that shared, at group level, similar characteristics in terms of population size, coffeeshops per capita and distance to the border. An online survey was launched and promoted using QR cards and social media adverts targeted at cannabis consumers in intervention cities and control cities to create a convenience sample of transactions. Questions included: Location of purchase; date of purchase; mode of purchase (street dealer, delivery, etc.), type of product, price paid, weight, reason for purchase on the illegal market, etc. Price and transaction trends in intervention cities are then compared to those in control cities.

Results: Baseline data collection is ongoing; first results will become available over the course of 2022.

Conclusion: The results offer insights in relevant developments on the market for illicit cannabis in the Netherlands over the course of the closed cannabis supply chain experiment. Both the results and the approach taken may inform scientists and policy makers in other countries where cannabis policies are evolving.


Presentation files

25 A6 1320 Stijn Hoorens.pdf1.35 MBDownload



Part of session