What does the first interim report on the Wietexperiment show?
The first interim report on the Wietexperiment in the Netherlands shows preliminary findings. According to the Rijksoverheid, the experiment runs in ten municipalities, and the experimental phase began on 7 April 2025. The results relate mainly to surveys carried out in autumn 2025 and are therefore only an interim picture. No final conclusions can be drawn from them.
What the experiment covers
The experiment is carried out in intervention municipalities and compared with comparison municipalities. According to the summary, the closed production chain for hash only came into force on 1 September 2025. The surveys ran from early September to the end of November 2025.
Anyone who wants to understand the findings should keep both groups in view. The comparison between intervention and comparison municipalities is the real message of the report.
The findings at a glance
| Area | Finding in the interim report |
|---|---|
| Supply | Almost all coffeeshops in the intervention municipalities offer edibles, and about six in ten sell vapes. |
| Purchase quantities of flowers | The typical purchase quantity rose in the intervention municipalities from 1 to 5 grams. In the comparison municipalities, 1 gram remained the most common. |
| Use | There were no significant differences in frequency of use, days of use or joints per day. The share of people who only use flowers rose more strongly in the intervention municipalities. |
| Illegal market | There are no clear signs of change. The amount of hash bought per purchase on the illegal market rose significantly in the intervention municipalities. According to the summary, this is probably due to initial shortages of legal hash products. |
| Crime and environment | No clear changes attributable to the experiment in harassment or offences. |
| Health | About three quarters of respondents rate their health as very good to good. |
What the findings do not show
According to the summary, the authors point out that consumers were overrepresented in the surveys. This limits how far the results can be applied to the general population. Specific sample sizes and percentages are largely missing from the summary, which is why the original report matters.
The illegal market cannot be fully assessed on the basis of the interim picture either. The report finds no clear signs of change, while the amount bought per purchase on the illegal market rose in the intervention municipalities. Both points have to be read together.
Prevention: do not overinterpret the findings
The fact that the interim report shows no clear changes in health or crime does not mean the experiment is free of risks. According to the summary, the survey ran from early September to the end of November 2025. Long-term consequences cannot be read from it.
The German KCanG sets a limit on passing on cannabis from cannabis associations to young adults: under § 19(3) KCanG, the THC content may not exceed 10 percent. This rule shows that the content is a protection point of its own in Germany as well. The article What role does the THC content play in the risk? explains the connection with risks.
What this means for Germany
Whether anything can be derived from the experiment for Germany is open. German law regulates shared cultivation through cannabis associations under § 11 KCanG. A comparison with coffeeshops is therefore only possible to a limited extent. Anyone making the comparison should set the different models side by side.
How the report is structured
The report compares intervention municipalities with comparison municipalities. It is based on surveys of coffeeshop visitors and on information about the supply. The findings are a snapshot and not an evaluation over a full year.
The distinction between finding and interpretation is important. A finding is that the typical purchase quantity for flowers rose from 1 to 5 grams in the intervention municipalities. An interpretation would be to conclude from this that consumers use more. Anyone quoting the report should keep this distinction.
What purchase quantities do and do not tell us
The purchase quantity describes how much someone buys in one transaction, not how much they consume in a week. A rise from 1 to 5 grams per purchase can also mean that purchases happen less often. Such questions can only be settled by the original report and its information on method.
For comparison with Germany: the KCanG sets limits on supply from cannabis associations. According to § 19(3) KCanG, members aged 21 and over may receive at most 25 grams per day and at most 50 grams per calendar month. Young adults may receive at most 25 grams per day and 30 grams per calendar month, and the THC content may not exceed 10 percent.
Health in the findings
About three quarters of respondents rate their health as very good to good, in both the intervention and the comparison municipalities alike. According to the summary, there are no significant differences in change. That sounds reassuring, but it says little about risks that only appear over a longer period. The BIÖG describes a link between cannabis and psychoses: people who use cannabis develop a psychosis more often than people who do not (cannabispraevention.de). A self-assessment of health cannot make such links visible.
How to read the original report
A summary leaves out details, and it is precisely the details that show how robust a finding is.
- Look for the sample size and the survey period.
- Check which municipalities are compared and how many there are.
- Note whether consumers are overrepresented and what that means for the conclusion.
- Distinguish between finding, interpretation and political demand.
What the interim report still leaves open
An interim report is a milestone. The analysis of the surveys is ongoing, and later reports may confirm or correct the findings. Anyone quoting it today should therefore state that this is a preliminary picture. This is especially true for figures on crime and the environment, where the report so far names no clear changes. If such a note is missing, it quickly looks as though the experiment has already shown a final effect. A second point concerns the comparison municipalities themselves: if they develop differently from what was expected without the trial, this changes the basis of comparison.
For classification, it is also worth looking at the comparison municipalities. Anyone who wants to know whether a difference really comes from the experiment has to check whether the groups were similar before the start. Such information belongs in the methods section of a report, and without it every comparison remains incomplete.
What you can do now
- Read the original report before you pass on figures or quote them.
- Compare the findings with the article What is the Wietexperiment in the Netherlands?
- When reading reports, pay attention to the difference between finding and interpretation.
Frequently asked questions
Does the Wietexperiment already have clear results?
The first interim report is preliminary. For health, crime and the illegal market it names no clear changes so far. For purchase quantities of flowers, it does show differences between the types of municipality. Final conclusions cannot be drawn from an interim report.
What does the closed supply chain for hash mean?
According to the summary, the closed production chain for hash came into force on 1 September 2025. The precise requirements are in the original report, so read them there before using the terms in your own texts.
Why are comparison municipalities important for the report?
Comparison municipalities show how the situation develops without the experiment. Only the difference between the two groups allows a statement about what can be attributed to the experiment. That is why the findings always have to be read in comparison.
Where can I find the original report?
The summary by the Deutscher Hanfverband dated 24 September 2026 is a secondary source from an interest group. Look for the original report on the Dutch government pages about the experiment and read it before quoting any figures.