title: Increasing the response rate of text messaging data collection: a delayed randomized controlled trial.
abstract: OBJECTIVE
  To test the effectiveness of multiple interventions on increasing the response rate of text messaging for longitudinal data collection.
  
  
  METHODS
  Our cohort included 283 caregivers of children aged 6-12 months who were participating in an anemia program in rural China. Using text messages to collect data on anemia medication adherence, we conducted a delayed randomized controlled trial to test multiple interventions (an additional four reminders; a ¥5.0 (US$0.79) credit reward for replying; and a feedback text message). After a 6-week pilot study with week 7 as the baseline measurement, we randomly allocated all participants into two groups: group 1 (n = 142) and group 2 (n = 141). During weeks 8-11, we introduced the interventions to group 1, and in weeks 12-15 the intervention was introduced to both groups. We compared the response rates between groups and explored factors affecting the response rate.
  
  
  RESULTS
  During weeks 8-11, the response rates in group 1 increased and were significantly higher than in group 2 (p<0.05). During weeks 12-15, the response rate increased significantly in group 2 (p>0.05) and slightly decreased in group 1. Younger participants or participants who had children with lower hemoglobin concentration were more likely to reply (p = 0.02). Sending four reminders on the second day contributed to only 286 (11.7%) extra text messages.
  
  
  CONCLUSIONS
  Our study showed that multiple interventions were effective in increasing response rate of text messaging data collection in rural China.
  
  
  CONCLUSIONS
  Larger multi-site studies are needed to find the most effective way of using these interventions to allow usage of text messaging data collection for health research.
authors.affiliation: Department of Integrated Early Childhood Development, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Integrated Early Childhood Development, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Integrated Early Childhood Development, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Global eHealth Unit, Department of Primary Care and Public Health, Imperial College London, London, UK.
authors.forename: Michelle Helena
authors.initials: MH
authors.lastname: van Velthoven
authors.affiliation: Department of Integrated Early Childhood Development, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Integrated Early Childhood Development, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Du
authors.affiliation: Department of Integrated Early Childhood Development, Capital Institute of Pediatrics, Beijing, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Centre for Population Health Sciences and Global Health Academy, University of Edinburgh Medical School, Edinburgh, UK.
authors.forename: Igor
authors.initials: I
authors.lastname: Rudan
authors.affiliation: Global eHealth Unit, Department of Primary Care and Public Health, Imperial College London, London, UK.
authors.forename: Josip
authors.initials: J
authors.lastname: Car
mesh_terms: D000328:Adult; D000740:Anemia / Q000188:drug therapy; D017028:Caregivers; D002681:China; D003625:Data Collection / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D007407:Interviews as Topic; D008297:Male; D010865:Pilot Projects; D012424:Rural Population; D060145:Text Messaging; D013997:Time Factors
keywords: nutrition surveys; program evaluation; randomized controlled trial