Brief Report| Volume 61, ISSUE 7, P718-721, July 2008

Differences in the contents of two randomized surveys of GPs' prescribing intentions affected response rates

  • Arash Rashidian
    Corresponding author. Department of Health Economics and Management, School of Public Health, Tehran University of Medical Sciences, Tehran 1417613191, Iran. Tel.: +98-21-88951391; fax: +98-21-88989129.
    Center for Academic and Health Policy (CAHP), Tehran University of Medical Sciences, Iran

    Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, UK
    Search for articles by this author
  • Jan van der Meulen
    Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, UK

    Clinical Effectiveness Unit, The Royal College of Surgeons of England, UK
    Search for articles by this author
  • Ian Russell
    Institute of Medical and Social Care Research, University of Wales, Bangor, UK
    Search for articles by this author



      We investigated the differences in response rates and the presence of response bias in two randomized surveys of prescribing intentions for statins and asthma.

      Study Design and Setting

      We conducted the surveys of British general practitioners (GPs) in 2002. The two surveys had similar designs, formats, administration time, administration methods, and target populations. We compared the response rates to the two surveys while controlling for the characteristics of respondents with nonrespondents. We also compared early respondents with late respondents and assessed heterogeneity in the answers of early and late respondents to two key questions.


      The response rates to the two surveys were significantly different (statins: 27%; asthma: 19%; P=0.002). We found no interaction between the survey type and any of the GP and practice characteristics we examined. The GPs' answers to the key questions did not differ regardless of the timing of the responses.


      We demonstrated that the surveys' contents significantly influenced the response rates. We found no evidence that the nonrespondents would have answered the key questions differently. Future studies should investigate the mechanisms by which contents of surveys may influence response rate.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Clinical Epidemiology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Cartwright A.
        Professionals as responders: variations in and effects of response rates to questionnaires, 1961-1977.
        BMJ. 1978; ii: 1419-1421
        • McAvoy B.R.
        • Kaner E.F.S.
        General practice postal surveys: a questionnaire too far?.
        BMJ. 1996; 313: 732-733
        • Templeton L.
        • Deehan A.
        • Taylor C.
        • Drummond C.
        • Strang J.
        Surveying general practitioners: does a low response rate matter?.
        Br J Gen Pract. 1997; 47: 91-94
        • Young J.
        Mail surveys of general practice physicians: response rates and non-response bias.
        Swiss Med Wkly. 2005; 135: 187-188
        • Sales A.E.
        • Plomondon M.E.
        • Magid D.J.
        • Spertus J.A.
        • Rumsfeld J.S.
        Assessing response bias from missing quality of life data: the Heckman method.
        Health Qual Life Outcomes. 2004; 2
        • Stocks N.
        • Gunnell D.
        What are the characteristics of general practitioners who routinely do not return postal questionnaires: a cross sectional study.
        J Epidemiol Community Health. 2000; 54: 940-941
        • Kaner E.F.
        • Haighton C.A.
        • McAvoy B.R.
        ‘So much post, so busy with practice—so, no time!’: a telephone survey of general practitioners' reasons for not participating in postal questionnaire surveys.
        Br J Gen Pract. 1998; 48: 1067-1069
        • Sibbald B.
        • Addington-Hall J.
        • Brenneman D.
        • Freeling P.
        Telephone versus postal surveys of general practitioners: methodological considerations.
        Br J Gen Pract. 1994; 44: 297-300
        • Barclay S.
        • Todd C.
        • Finlay I.
        • Grande G.
        • Wyatt P.
        Not another questionnaire! Maximizing the response rate, predicting non-response and assessing non-response bias in postal questionnaire studies of GPs.
        Fam Pract. 2002; 19: 105-111
        • Jepson C.
        • Asch D.A.
        • Hershey J.C.
        • Ubel P.A.
        In a mailed physician survey, questionnaire length had a threshold effect on response rate.
        J Clin Epidemiol. 2005; 58: 103-105
        • Rashidian A.
        • Eccles M.P.
        • Russell I.
        Falling on stony ground? A qualitative study of implementation of clinical guidelines prescribing recommendations in primary care.
        Health Policy. 2008; 86: 148-161
        • Rashidian A.
        • Miles J.
        • Russell D.
        • Russell I.
        Sample size for regression analyses of theory of planned behaviour studies: case of prescribing in general practice.
        Br J Health Psychol. 2006; 11: 581-593
        • Edwards P.
        • Roberts I.
        • Clarke M.
        • DiGuiseppi C.
        • Pratap S.
        • Wentz R.
        • Kwan I.
        Increasing response rates to postal questionnaires: systematic review.
        BMJ. 2002; 324: 1183-1185
        • Thomson C.E.
        • Paterson-Brown S.
        • Russell D.
        • McCaldin D.
        • Russell I.T.
        Encouraging GPs to complete postal questionnaires–one big prize or many small prizes? A randomized controlled trial.
        Fam Pract. 2004; 21: 697-698
        • Leung G.M.
        • Ho L.M.
        • Chan M.F.
        • Johnston J.M.
        • Wong F.K.
        The effects of cash and lottery incentives on mailed surveys to physicians: a randomized trial.
        J Clin Epidemiol. 2002; 55: 801-807
        • McColl E.
        • Jacoby A.
        • Thomas A.
        • Soutter J.
        • Bamford C.
        • Steen N.
        • et al.
        Design and use of questionnaires: a review of best practice applicable to surveys of health service staff and patients.
        Health Technol Assess. 2001; 5
        • Majeed A.
        • Evans N.
        • Head P.
        What can PACT data tell us about prescribing in general practice?.
        BMJ. 1997; 315: 1515-1519
        • Montori V.M.
        • Leung T.W.
        • Walter S.D.
        • Guyatt G.H.
        Procedures that assess inconsistency in meta-analyses can assess the likelihood of response bias in multiwave surveys.
        J Clin Epidemiol. 2005; 58: 856-858
        • Cull W.L.
        • O'Connor K.G.
        • Sharp S.
        • Tang S.S.
        Response rates and response bias for 50 surveys of pediatricians.
        Health Serv Res. 2005; 40: 213-226