title: Improving shop floor compliance with age restrictions for alcohol sales: effectiveness of a feedback letter intervention.
abstract: OBJECTIVE
  In this study, we investigated the effects and handling of an intervention to increase compliance with age limits regarding alcohol sales. The intervention tested in this field experiment was a feedback letter sent to alcohol outlets about their individual compliance results based on a mystery shopping study.
  
  
  METHODS
  We measured compliance in 146 alcohol outlets (cafeterias, supermarkets, bars, liquor stores and youth centres) in one region in the Netherlands with 15-year-old mystery shoppers. About half (n=72) of the outlets received the intervention letter (the experimental group). After this intervention, we measured compliance again (n=138). Then we sent the same letter to the control group and interviewed all the outlets regarding their handling of the intervention (n=106).
  
  
  RESULTS
  After the experimental group received the letter, compliance increased significantly (from 18.1% to 32.4%). In the control group, compliance did not change. Of the outlets interviewed, 81% stated that they had received the letter, and the action most commonly taken was to bring the letter to the attention of their staff.
  
  
  CONCLUSIONS
  Positive feedback letters are more often copied and shared integrally with personnel, compared with negative letters. Compliance with respect to underage alcohol sales can be improved, although compliance levels remain low in the Netherlands.
authors.affiliation: Communication Studies, University of Twente, Enschede, The Netherlands. j.j.vanhoof@utwente.nl
authors.forename: Joris J
authors.initials: JJ
authors.lastname: Van Hoof
authors.forename: Jordy F
authors.initials: JF
authors.lastname: Gosselt
authors.forename: Niels
authors.initials: N
authors.lastname: Baas
authors.forename: Menno D T
authors.initials: MD
authors.lastname: De Jong
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000428:Alcohol Drinking / Q000331:legislation & jurisprudence*; D000434:Alcoholic Beverages / Q000191:economics / Q000600:supply & distribution*; D003132:Commerce / Q000331:legislation & jurisprudence* / Q000706:statistics & numerical data; D005246:Feedback; D005260:Female; D033161:Government Regulation; D019983:Guideline Adherence; D006801:Humans; D008297:Male; D033242:Minors / Q000331:legislation & jurisprudence* / Q000706:statistics & numerical data; D009426:Netherlands; D012737:Sex Factors