Electronic prompts significantly increase response rates to postal questionnaires: a randomized trial within a randomized trial and meta-analysis

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OBJECTIVES: To assess the effectiveness of sending electronic prompts to randomized controlled trial participants to return study questionnaires.

STUDY DESIGN AND SETTING: A "trial within a trial" embedded within a study determining the effectiveness of chronic obstructive pulmonary disease (DOC) screening on smoking cessation. Those participants taking part in DOC who provided a mobile phone number and/or an electronic mail address were randomized to either receive an electronic prompt or no electronic prompt to return a study questionnaire. The results were combined with two previous studies in a meta-analysis.

RESULTS: A total of 437 participants were randomized: 226 to the electronic prompt group and 211 to the control group. A total of 285 (65.2%) participants returned the follow-up questionnaire: 157 (69.5%) in the electronic prompt group and 128 (60.7%) in the control group [difference 8.8%; 95% confidence interval (CI): -0.11%, 17.7%; P = 0.05]. The mean time to response was 23 days in the electronic prompt group and 33 days in the control group (hazard ratio = 1.27; 95% CI: 1.105, 1.47). The meta-analysis of all three studies showed an increase in response rate of 7.1% (95% CI: 0.8%, 13.3%).

CONCLUSION: The use of electronic prompts increased response rates and reduces the time to response.

Original languageEnglish
Pages (from-to)1446-1450
Number of pages5
JournalJournal of Clinical Epidemiology
Issue number12
Early online date27 Jan 2015
Publication statusPublished - Dec 2015

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