Experimental Design
Context:
In May 2021, the Swiss government amended the Federal Narcotics Act (NarcA), enabling pilot trials for recreational cannabis under the BetmPV ordinance (BetmPV, 2021). Our study is part of a pilot trial in the Canton of St. Gallen and is conducted in collaboration with our field partner, the non-profit Cannabis Research Association (Verein Cannabis Research, VCR). VCR is responsible for the operational and legal aspects of the pilot trial, including establishing distribution channels and serving as the primary point of contact for study participants. The research team is responsible for the study design and independent scientific evaluation.
The pilot trial comprises two parts that draw on a common subject pool but address independent research questions.
Part 1 (preregistered separately as AEARCTR-0018999) precedes Part 2 and studies the WTP for legal cannabis.
Part 2 (this pre-registration) is a randomized controlled trial (RCT) that measures the social and economic effects of cannabis legalization (including the effects of different distribution channels), as detailed in this pre-registration
Recruitment and Eligibility:
Part 1 and Part 2 of the pilot trial draw from a common participant pool. Screening and eligibility assessment are conducted jointly for both parts and follow the inclusion and exclusion criteria defined in the federal regulation (Article 14 BetmPV, 2021).
The study uses a cohort-based rollout. Recruitment and eligibility screening occur continuously, but participation begins at fixed points in time. Cohorts are initiated approximately every two to three months. All participants who are considered eligible by a given cutoff date enter the study together as a cohort.
Within each cohort, participants are randomly assigned to either Part 1 or directly to Part 2. Assignment to Part 1 will continue until either (i) the overall target sample size of 2,500 participants who have completed both Survey 1 and Survey 2 is reached or (ii) two years of enrollment have elapsed. The remaining participants proceed directly to Part 2 without participating in Part 1. Part 1 has a duration of approximately ten weeks (including a four week buffer period). Only those participants who complete all required surveys in Part 1 are eligible to continue to Part 2. Part 1 includes a four week buffer period before the start of Part 2. Participants who are not assigned to Part 1 enter Part 2 after a waiting period of approximately ten weeks.
The share of participants randomly selected for Part 1 within each cohort depends on the number of eligible applicants. For Part 1 we aim for a total of 2,500 participants who have completed both Survey 1 and Survey 2. For Part 2 we aim to recruit 5,000 participants, with enrollment ending two years after the start of the first cohort. We additionally recruit up to 10 participants for an initial test cohort. This cohort will start before the official launch and is intended to test all study procedures. Data from the test cohort will not be included in the main analysis.
Randomization and Treatment Assignment:
In Part 2 participants will be randomly assigned (further details on randomization below) to one of the three experimental conditions.
Data Collection:
The analyses are primarily based on administrative data from VCR (consumption of legal cannabis) and administrative register data (labor market outcomes, criminal behavior, educational attainment). In addition, we will conduct regular online surveys administered through Qualtrics to measure the consumption of illegal cannabis and other substances. Additionally, we are collecting descriptive data on the development of illegal cannabis quality (assessed through laboratory analysis) over the course of the RCTs.