title: Self-reported frequency of drinking assessed with a closed- or open-ended question format: a split-sample study in Switzerland.
abstract: OBJECTIVE
  This study was designed to determine whether reporting of drinking frequency differed according to whether the question asked was open or closed ended.
  
  
  METHODS
  In a split-sample design with 994 participants responding to a questionnaire, the question on usual frequency of drinking for one sample (n = 457) was open ended, and for the other (n = 537) was closed ended (participants were offered seven response alternatives, ranging from "three times a day" to "never").
  
  
  RESULTS
  The closed-ended question elicited higher frequencies of drinking than the open-ended question. No significant interactions could be found between sociodemographic background variables and question format.
  
  
  CONCLUSIONS
  This study does not support the general recommendation of survey methodologists that questions about frequency of behavior be open ended.
authors.affiliation: Research Department, Swiss Institute for the Prevention of Alcohol and Drug Problems, Lausanne.
authors.forename: G
authors.initials: G
authors.lastname: Gmel
authors.forename: O
authors.initials: O
authors.lastname: Lokosha
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology* / Q000523:psychology; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011795:Surveys and Questionnaires; D013557:Switzerland / Q000453:epidemiology