Het besloten club- en het ingezetenencriterium voor coffeeshops Een natuurlijk experiment

The retail sale of cannabis in coffee shops is tolerated in the Netherlands, provided that certain criteria are met. Two criteria were added in 2012: the private club and the residence criterion. The plan was to implement them first in the southern provinces and later in the other provinces. This created an opportunity for a natural experiment. In an experimental group of seven municipalities in the south and a matched comparison group of municipalities in the other part of the country pre- and post-measurements were conducted. The size of the drug tourism, the number of visits to coffee shops, the illegal cannabis consumer market and the nuisance experienced in the direct vicinity of coffee shops was assessed. Robust changes occurred in the experimental group after implementation of the new criteria. Initial differences between the groups and variation in local implementation caused doubts about drawing causal conclusions. This article analyzes whether such conclusions can be drawn. We conclude that due to the broad design of the research it appears that the observed changes can be attributed to the new criteria despite the methodological shortcomings in the study.