Prenotification had no additional effect on the response rate and survey quality: A randomized trial

Objectives: To determine the effect of prenotification package on survey quality, including response rates, response time, percentage of nonresponse items, and cost. Study Design and Setting: Participants were randomized into two groups. In the first round mailing, participants in prenotification group received a prenotification package, whereas direct questionnaire mailing group participants received a questionnaire with prepaid return envelope only. In the second round mailing, both groups received the questionnaires. The trial was integrated into a study among 35-65-year-old female nurses in Hong Kong. Results: A total of 367 nurses were included in the trial. A total of 362 mails were successfully delivered. The initial response rate in the first round mailing were 8.79% and 8.89% for prenotification and direct questionnaire mailing groups, respectively. After the second round mailing, the final response rate in prenotification and direct questionnaire mailing groups were 17.58% and 17.22%, respectively; no significant difference was found between the groups. There were no differences with respect to percentage of nonresponse items or response time, but the cost of prenotification group was HK$ 15.11 per response higher than direct mailing group. Conclusion: Prenotification had no additional effect on the response rate and other survey quality compared with direct questionnaire mailing in a Hong Kong population.