title: Electronic prompts significantly increase response rates to postal questionnaires: a randomized trial within a randomized trial and meta-analysis.
abstract: OBJECTIVE
  To assess the effectiveness of sending electronic prompts to randomized controlled trial participants to return study questionnaires.
  
  
  METHODS
  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%).
  
  
  CONCLUSIONS
  The use of electronic prompts increased response rates and reduces the time to response.
authors.affiliation: York Trials Unit, Department of Health Sciences, Heslington University of York, York YO10 5DD, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Clark
authors.affiliation: York Trials Unit, Department of Health Sciences, Heslington University of York, York YO10 5DD, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Ronaldson
authors.affiliation: York Trials Unit, Department of Health Sciences, Heslington University of York, York YO10 5DD, UK.
authors.forename: Lisa
authors.initials: L
authors.lastname: Dyson
authors.affiliation: York Trials Unit, Department of Health Sciences, Heslington University of York, York YO10 5DD, UK.
authors.forename: Catherine
authors.initials: C
authors.lastname: Hewitt
authors.affiliation: York Trials Unit, Department of Health Sciences, Heslington University of York, York YO10 5DD, UK. Electronic address: david.torgerson@york.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Torgerson
authors.affiliation: York Trials Unit, Department of Health Sciences, Heslington University of York, York YO10 5DD, UK.
authors.forename: Joy
authors.initials: J
authors.lastname: Adamson
mesh_terms: D000328:Adult; D000368:Aged; D034742:Electronic Mail; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000517:prevention & control*; D017010:Reminder Systems; D016540:Smoking Cessation / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D060145:Text Messaging
keywords: Data collection; Electronic mail; Randomized trial; Reminder system; Research methodology; Short messenger service