Estimating the size of the cannabis market

• Author: Singleton, Nicola; Kalamara, Eleni; Noor, André
• Pages: 13-20

TECHNICALREPORTIEstimatingthesizeofthemainillicitretaildrugmarketsinEurope:anupdate

13

3Estimatingthesizeofthecannabismarket

Cannabisisthemostfrequentlyuseddrugandhencethedataavailablerelatingtoitsusearerelatively

comprehensiveandrobust.Generalpopulationsurveyswereusedastheprimarysourceofdataonthe

numberofcannabisusersintheyear,whowerecategorisedintofourdifferentusergroups,accordingto

frequencyofuse.Inaddition,acorrectionwasmadeforundercoverageofhighriskopioidusers,whomay

alsofrequentlyusecannabis,withinthesesurveys.

Improvementsintheestimationprocessinthissecondroundofestimationsweremadeinthreemainareas.

Informationonamountsusedwereavailablefor15EUcountriesfromtheEuropeanWebSurveyon

Drugs(EWSD)(Matiasetal.,2019),partiallyaddressingadatagapidentifiedintheprevious

estimationbymorethandoublingthenumberofcountrieswithavailabledata.Inthepreviousround

ofestimatesweonlyhaddatafromfivecountries.

InformationonthetypeofcannabisusedwasalsoavailablefromtheEWSD,allowingadistinctionto

bemadebetweenamountsusedforherbandresinandapartitionofthemarketintothesetwo

groupsonthebasisofdemanddata.Thepreviousestimationreliedonseizuredatatopartitionthe

market.

ImprovementstotheroutinedatacollectionsattheEMCDDAhavereducedslightlytheneedfor

imputationandalsoprovidemoreuptodateinformationfortheestimationprocess.

Thedecisionsmadeaboutthedatatobeusedwithintheestimates,imputationprocessesandassumptions

madearedescribedforeachcomponentofthebasicmodelbelow.Thedatausedintheestimationprocess

areshowninTables1aand1b.

3.1Numberofcannabisusers

Numberofcannabisusersinthegeneralpopulation

CannabisusersaremainlywellintegratedinsocietyandlikelytobequitewellrepresentedinGPS.Within

Europe,mostcountrieshaveafairlyrecentGPSthatincludesquestionsonuseinthelastyearandthelast

month,andonfrequencyofuse(mostoftenrelatingtouseinthelastmonthbutsometimesinthelastyear).

ThesedataarereportedtotheEMCDDAroutinely,andthenumberofcannabisusersincludedinthesurveysis

generallysufficientlylargetoenableestimatesoftheprevalenceofdifferenttypesofuserstobeconstructed

formostcountries.Therefore,fortheestimateofnumbersofpeoplewhousecannabis,GPSdatahavebeen

usedasthemainsourceofdataforthemarketsizeestimatesusingthesameapproachasusedintheprevious

estimatespublishedin2016(EMCDDA,2016).

Aswasthecaseforthepreviousmarketsizeestimates,totakeaccountoftheconsiderablevariationsin

amountsofcannabispeopleuseperyeardependingontheirfrequencyofuse,thenumbersofpeoplewhouse

cannabisneedtobedividedintosubgroupsonthebasisoftheirfrequencyofuse.Foreachcountry,those

whohadusedcannabisinthelastyearweresubdividedintofourgroupsbasedontheirresponsestotheGPS

questionsontheiruseofcannabisinthelastyearandlastmonth,andfrequencyofuse.However,thewayin

whichfrequencyofuseisascertainedvariesbetweencountries,withsomeaskingaboutnumberofdaysin

whichdrugswereusedandothersarepresentingfrequencygroups,suchas‘lessthanonceaweek’.The

estimatesofquantitiesofcannabisarenotavailableintheGPSandareobtainedfromtheEWSD,whichasks

slightlydifferentquestionsonfrequencyofuse.Soitwasnecessarytoidentifygroupingsthatapproximated,

asnearlyaspossible,thosethathadbeenusedinthepreviousstudy,whichhadbeenoriginallydevelopedin

thestudybyvanLaaretal.(2013).