title: Maximising follow-up participation rates in a large scale 45 and Up Study in Australia.
abstract: BACKGROUND
  The issue of poor response rates to population surveys has existed for some decades, but few studies have explored methods to improve the response rate in follow-up population cohort studies.
  
  
  METHODS
  A sample of 100,000 adults from the 45 and Up Study, a large population cohort in Australia, were followed up 3.5 years after the baseline cohort was assembled. A pilot mail-out of 5000 surveys produced a response rate of only 41.7 %. This study tested methods of enhancing response rate, with three groups of 1000 each allocated to (1) receiving an advance notice postcard followed by a questionnaire, (2) receiving a questionnaire and then follow-up reminder letter, and (3) both these strategies.
  
  
  RESULTS
  The enhanced strategies all produced an improved response rate compared to the pilot, with a resulting mean response rate of 53.7 %. Highest response was found when both the postcard and questionnaire reminder were used (56.4 %) but this was only significantly higher when compared to postcard alone (50.5 %) but not reminder alone (54.1 %). The combined approach was used for recruitment among the remaining 92,000 participants, with a resultant further increased response rate of 61.6 %.
  
  
  CONCLUSIONS
  Survey prompting with a postcard and a reminder follow-up questionnaire, applied separately or combined can enhance follow-up rates in large scale survey-based epidemiological studies.
authors.affiliation: Prevention Research Collaboration, Level 6 Charles Perkins Centre D17, Sydney School of Public Health, University of Sydney, Sydney, NSW 2006 Australia.
authors.forename: Adrian
authors.initials: A
authors.lastname: Bauman
authors.affiliation: Prevention Research Collaboration, Level 6 Charles Perkins Centre D17, Sydney School of Public Health, University of Sydney, Sydney, NSW 2006 Australia.
authors.forename: Philayrath
authors.initials: P
authors.lastname: Phongsavan
authors.affiliation: Sax Institute, University of Technology, PO Box K617, Haymarket, NSW 1240 Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Cowle
authors.affiliation: National Centre for Epidemiology and Population Health, Australian National University, Building 62, Acton, ACT 0200 Australia.
authors.forename: Emily
authors.initials: E
authors.lastname: Banks
authors.affiliation: Centre for Big Data Research in Health, Faculty of Medicine, University of New South Wales, Sydney, NSW 2052 Australia.
authors.forename: Louisa
authors.initials: L
authors.lastname: Jorm
authors.affiliation: The George Institute for Global Health, PO Box M201, Missenden Road, Camperdown, NSW 2050 Australia.
authors.forename: Kris
authors.initials: K
authors.lastname: Rogers
authors.affiliation: School of Public Health and Community Medicine, University of New South Wales, Sydney, Australia ; Centre for Research, Evidence Management and Surveillance, Locked Bag 7279, Liverpool, NSW 1871 Australia.
authors.forename: Bin
authors.initials: B
authors.lastname: Jalaludin
authors.affiliation: Prevention Research Collaboration, Level 6 Charles Perkins Centre D17, Sydney School of Public Health, University of Sydney, Sydney, NSW 2006 Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Grunseit
keywords: Epidemiological studies; Follow-up; Recruitment strategies; Response rates