title: Estimating the production, consumption and export of cannabis: The Dutch case.
abstract: Quantifying an illegal phenomenon like a drug market is inherently complex due to its hidden nature and the limited availability of reliable information. This article presents findings from a recent estimate of the production, consumption and export of Dutch cannabis and discusses the opportunities provided by, and limitations of, mathematical models for estimating the illegal cannabis market.
  
  
  
  The data collection consisted of a comprehensive literature study, secondary analyses on data from available registrations (2012-2014) and previous studies, and expert opinion. The cannabis market was quantified with several mathematical models. The data analysis included a Monte Carlo simulation to come to a 95% interval estimate (IE) and a sensitivity analysis to identify the most influential indicators.
  
  
  
  The annual production of Dutch cannabis was estimated to be between 171 and 965tons (95% IE of 271-613tons). The consumption was estimated to be between 28 and 119tons, depending on the inclusion or exclusion of non-residents (95% IE of 51-78tons or 32-49tons respectively). The export was estimated to be between 53 and 937tons (95% IE of 206-549tons or 231-573tons, respectively).
  
  
  
  Mathematical models are valuable tools for the systematic assessment of the size of illegal markets and determining the uncertainty inherent in the estimates. The estimates required the use of many assumptions and the availability of reliable indicators was limited. This uncertainty is reflected in the wide ranges of the estimates. The estimates are sensitive to 10 of the 45 indicators. These 10 account for 86-93% of the variation found. Further research should focus on improving the variables and the independence of the mathematical models.
authors.affiliation: Erasmus University Rotterdam, Rotterdam School of Management - Centre of Excellence in Public Safety Management, Burgemeester Oudlaan 50, 3062 PA, Rotterdam, The Netherlands. Electronic address: vandergiessen@rsm.nl.
authors.forename: Mark
authors.initials: M
authors.lastname: van der Giessen
authors.affiliation: Research and Documentation Centre, Ministry of Security and Justice, Turfmarkt 147, 2511 DP The Hague, The Netherlands.
authors.forename: Marianne M J
authors.initials: MM
authors.lastname: van Ooyen-Houben
authors.affiliation: Research and Documentation Centre, Ministry of Security and Justice, Turfmarkt 147, 2511 DP The Hague, The Netherlands.
authors.forename: Debora E G
authors.initials: DE
authors.lastname: Moolenaar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002188:Cannabis / Q000254:growth & development*; D003132:Commerce / Q000191:economics / Q000458:organization & administration; D064423:Drug Trafficking / Q000191:economics; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000191:economics / Q000453:epidemiology*; D008385:Marijuana Smoking / Q000191:economics / Q000453:epidemiology*; D008875:Middle Aged; D008962:Models, Theoretical; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D013997:Time Factors; D055815:Young Adult
keywords: Cannabis consumption; Cannabis export; Cannabis production; Estimating illegal drug markets; Netherlands cannabis