title: Improving response rate and quality of survey data with a scratch lottery ticket incentive.
abstract: BACKGROUND
  The quality of data collected in survey research is usually indicated by the response rate; the representativeness of the sample, and; the rate of completed questions (item-response). In attempting to improve a generally declining response rate in surveys considerable efforts are being made through follow-up mailings and various types of incentives. This study examines effects of including a scratch lottery ticket in the invitation letter to a survey.
  
  
  METHODS
  Questionnaires concerning oral health were mailed to a random sample of 2,400 adults. A systematically selected half of the sample (1,200 adults) received a questionnaire including a scratch lottery ticket. One reminder without the incentive was sent.
  
  
  RESULTS
  The incentive increased the response rate and improved representativeness by reaching more respondents with lower education. Furthermore, it reduced item nonresponse. The initial incentive had no effect on the propensity to respond after the reminder.
  
  
  CONCLUSIONS
  When attempting to improve survey data, three issues become important: response rate, representativeness, and item-response. This study shows that including a scratch lottery ticket in the invitation letter performs well on all the three.
authors.affiliation: Institute of Community Medicine, Faculty of Health Sciences, University of Tromsø, Norway. frank.olsen@skde.no
authors.forename: Frank
authors.initials: F
authors.lastname: Olsen
authors.forename: Birgit
authors.initials: B
authors.lastname: Abelsen
authors.forename: Jan Abel
authors.initials: JA
authors.lastname: Olsen
mesh_terms: D000328:Adult; D015982:Bias; D003256:Community Participation / Q000379:methods* / Q000706:statistics & numerical data; D035061:Control Groups; D003362:Cost-Benefit Analysis; D005260:Female; D006306:Health Surveys / Q000191:economics / Q000379:methods*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009664:Norway; D009909:Oral Health; D011177:Postal Service; D045808:Refusal to Participate / Q000706:statistics & numerical data; D017010:Reminder Systems / Q000191:economics; D012111:Residence Characteristics; D012201:Reward; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires