Table 1

Search strategy

PhaseTechniqueProcedureSearch dates
Phase 1Snowball samplingWe initially searched the following search terms: ‘size’; ‘pack size’; ‘package size’; ‘amount’; ‘number’; ‘weight’; ‘volume’; ‘portion’; ‘packet’; ‘pouch’; ‘carton’; ‘can size’; ‘tin size’; ‘pouch size’; ‘pouch count’; ‘(collection: ‘Marketing to Youth’) AND ‘package size’)’. These terms were based on initial guesses about how companies may have referred to package quantity. Additional search terms identified when screening and reviewing the initial documents included ‘package size configuration’; ‘half pack’; ‘mini pack’; ‘10’s pack’; ‘5 s’; ‘10 s’; ‘12 s’; ‘value pack’; ‘25 s’; ‘bulk package’; ‘bulk packaging’. Finally, additional documents were located using the TTID’s ‘more like this’ feature and by viewing adjacent Bates numbers. For each search, we screened the first 200 documents returned for relevance. Phase 1 was considered complete when we no longer found new search terms, research findings or motivating factors for package quantity changes. Phase 1 located 53 relevant documents, including 43 concerning cigarettes, six concerning smokeless tobacco and four concerning roll-your-own tobacco.15 June 2015 to 27 April 2016
Phase 2Static searchWe entered the following search string on September 22, 2017: ((("pack size" OR "package size" OR "can size" OR "tin size" OR "pouch count") AND ("half pack" OR "mini pack" OR "bulk pack" OR "Project Orville" OR "Project Buck" OR "kiddie pack" OR "Project Silver" OR "Craven A" OR "Packaging Evaluation Study" OR "Black Smoker Study" OR "10-pack" OR "10’s" OR "5-pack" OR "5’s" OR "12-pack" OR "12’s" OR "14-pack" OR "14’s" OR "15-pack" OR "15’s" OR "25-pack" OR "25’s")) AND ("plan" OR "report" OR "evaluation")) NOT ("invoice" OR "compliance report" OR "distribution summary" OR "purchase order" OR "docket" OR "product analytical" OR "Cigarette Information Report"). The search returned 3311 results. We screened all of these documents for relevance. Phase 2 located 113 relevant documents that were not covered in phase 1, including 112 concerning cigarettes and one concerning ‘smokeless cigarettes.’18 September to 28 October 2017
Phase 3Follow-up snowball search of additional termsWe searched the following terms and strings, plus the adjacent Bates numbers of any relevant documents located: "black smoker study" and "10 pack"; "Project Orville"; "Project Buck"; "Project Silver"; "pack size" AND ("consumer pull-out" OR "consumer pullout"); "15’s format"; "cigarette segmentation study" AND "pack size"; "pack size" AND "rationing"; title:("pack size"); title:("trial pack"); "pack size starter"~20; "package size starter"~20; "pack size consumption"~10 NOT "docket" NOT "commons" NOT "american society"; "buying habits study" AND ("pack size" OR "package size"); "buyer’s study" AND "pack size"; "Packaging Evaluation Study"; "Black Smoker Study" AND "package size"; "Black Smoker Study" AND "pack size"; "Rationalisation of Pack Size"; "Package Size Evaluation Study"; "Package Size Test"; "12-count pack"; "Pack Size Dynamics"; "Project Delta" AND "pack size"; "new consumers/YAS" AND "pack size"; title:("10’s pack"); title:("12-pack"); title:"van program" AND "10 pack"; title:"package size". The searches returned approximately 800 documents in total. We screened all of these documents for relevance. Phase 3 located 50 relevant documents that were not covered in phases 1 or 2, including 45 documents on cigarettes and five documents on roll-your-own tobacco.19 January 19 to 22 February 2018