Data on fertility issues among female childhood cancer survivors: Differences in response characteristics

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.