title: Using web-based and paper-based questionnaires for collecting data on fertility issues among female childhood cancer survivors: differences in response characteristics.
abstract: BACKGROUND
  Web-based questionnaires have become increasingly popular in health research. However, reported response rates vary and response bias may be introduced.
  
  
  OBJECTIVE
  The aim of this study was to evaluate whether sending a mixed invitation (paper-based together with Web-based questionnaire) rather than a Web-only invitation (Web-based questionnaire only) results in higher response and participation rates for female childhood cancer survivors filling out a questionnaire on fertility issues. In addition, differences in type of response and characteristics of the responders and nonresponders were investigated. Moreover, factors influencing preferences for either the Web- or paper-based version of the questionnaire were examined.
  
  
  METHODS
  This study is part of a nationwide study on reproductive function, ovarian reserve, and risk of premature menopause in female childhood cancer survivors. The Web-based version of the questionnaire was available for participants through the Internet by means of a personalized user name and password. Participants were randomly selected to receive either a mixed invitation (paper-based questionnaire together with log-in details for Web-based questionnaire, n = 137) or a Web-only invitation (log-in details only, n = 140). Furthermore, the latter group could request a paper-based version of the questionnaire by filling out a form.
  
  
  RESULTS
  Overall response rates were comparable in both randomization groups (83% mixed invitation group vs 89% in Web-only invitation group, P = .20). In addition, participation rates appeared not to differ (66% or 90/137, mixed invitation group vs 59% or 83/140, Web-only invitation group, P =.27). However, in the mixed invitation group, significantly more respondents filled out the paper-based questionnaire compared with the Web-only invitation group (83% or 75/90 and 65% or 54/83, respectively, P = .01). The 44 women who filled out the Web-based version of the questionnaire had a higher educational level than the 129 women who filled out the paper-based version (P = .01). Furthermore, the probability of filling out the Web-based questionnaire appeared to be greater for women who were allocated to the Web-only invitation group (OR = 2.85, 95% CI 1.31-6.21), were older (OR = 1.08, 95% CI 1.02-1.15), had a higher educational level (OR high vs low = 0.06, 95% CI 0.01-0.52), or were students (OR employed vs student = 3.25, 95% CI 1.00-10.56).
  
  
  CONCLUSIONS
  Although overall response as well as participation rates to both types of invitations were similar, adding a paper version of a questionnaire to a Web-only invitation resulted in more respondents filling out the paper-based version. In addition, women who were older, had a higher level of education, or were students, were more likely to have filled out the Web-based version of the questionnaire. Given the many advantages of Web-based over paper-based questionnaires, researchers should strongly consider using Web-based questionnaires, although possible response bias when using these types of questionnaires should be taken into account.
  
  
  BACKGROUND
  Nederlands Trial Register NTR2922; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2922 (Archived by WebCite at http://www.webcitation.org/5zRRdMrDv).
authors.affiliation: VU University Medical Center Amsterdam, Department of Pediatrics, division of Oncology-Hematology, Amsterdam, Netherlands. mh.vandenberg@vumc.nl
authors.forename: Marleen H
authors.initials: MH
authors.lastname: van den Berg
authors.forename: Annelies
authors.initials: A
authors.lastname: Overbeek
authors.forename: Helena J
authors.initials: HJ
authors.lastname: van der Pal
authors.forename: A Birgitta
authors.initials: AB
authors.lastname: Versluys
authors.forename: Dorine
authors.initials: D
authors.lastname: Bresters
authors.forename: Flora E
authors.initials: FE
authors.lastname: van Leeuwen
authors.forename: Cornelis B
authors.initials: CB
authors.lastname: Lambalk
authors.forename: Gertjan J L
authors.initials: GJ
authors.lastname: Kaspers
authors.forename: Eline
authors.initials: E
authors.lastname: van Dulmen-den Broeder
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D016001:Confidence Intervals; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology / Q000517:prevention & control*; D020407:Internet / Q000706:statistics & numerical data*; D009369:Neoplasms / Q000534:rehabilitation; D009426:Netherlands / Q000453:epidemiology; D016017:Odds Ratio; D057240:Patient Preference / Q000706:statistics & numerical data*; D011594:Psychometrics; D011795:Surveys and Questionnaires / Q000592:standards*; D017741:Survivors / Q000523:psychology / Q000706:statistics & numerical data*; D055815:Young Adult