Research into the effects of a controlled cannabis supply chain

During the experiment researchers will study the effects of controlled cannabis supply chain on crime, public order, safety and public health. Their findings will determine whether the controlled cannabis supply chain has been a success and whether the government should reconsider its policy with regard to ‘coffee shops’ (the local term for cannabis cafés).

Four phases of research during the experiment

The research into the effects of a closed cannabis supply chain has been commissioned by the Research and Data Centre (WODC). The researchers are from the organisations Breuer&Intraval RAND Europe and the Trimbos Institute.

During the experiment the research team will collect data for a wide range of indicators. Their research findings will inform decisions on the future of the coffee shop policy. The research consists of four phases:

  1. Preliminary survey in 2021. This survey provided a reference picture of the situation with regard to cannabis and coffee shops at that time. This data was initially collected for the purposes of a baseline survey (see point 2). Because the experiment was delayed, it was decided to use the results from 2021 as a preliminary measurement. A baseline survey was then conducted in 2022.
  2. Baseline survey in 2022. This survey was conducted before the start of the experiment. Researchers used the baseline survey to substantiate the policy theory underpinning the experiment. The data collected also serves as a starting point and subsequent measurements can be compared with it.
  3. Monitoring. During the experimental phase, the researchers will perform annual interim surveys to monitor the effects on crime, safety and public health. The findings of these surveys will be presented in annual reports.
  4. Evaluation. An evaluation will be conducted approximately two and a half years after the start of the experimental phase, to determine the extent to which the experiment’s objectives have been achieved.
  5. The data collected for the surveys will be aggregated, meaning the findings will relate to the experiment as a whole, not to individual coffee shops or municipalities. These reports will be presented to the House of Representatives and published. Coffee shop owners will receive information about this by email.

Independent guidance and evaluation committee

An independent guidance and evaluation committee will fulfil an advisory role during the evaluation of the research. The committee members have been appointed by the Research and Data Centre (WODC) and include independent experts in the areas of public health, safety, municipal public administration and scientific methodology. The committee will use the research results to make recommendations, if necessary, to the relevant ministers.

Other studies during the experiment

During the experiment other studies will also be conducted: