Standard Protocol Items: Recommendation For Interventional Trials (SPIRIT). Available at: https://www.spirit-statement.org/. Accessed 16 Mar 2019.
Fewtrell MS, Kennedy K, Singhal A, Martin RM, Ness A, Hadders-Algra M, et al. How much loss to follow-up is acceptable in long-term randomised trials and prospective studies? Arch Dis Child. 2008 Jun;93(6):458–61.
Wood AM, White IR, Thompson SG. Are missing outcome data adequately handled? A review of published randomized controlled trials in major medical journals. Clinical trials. 2004;1(4):368–76.
Walters SJ, Bonacho Dos Anjos Henriques-Cadby I, Bortolami O, Flight L, Hind D, Jacques RM, et al. Recruitment and retention of participants in randomised controlled trials: a review of trials funded and published by the United Kingdom Health Technology Assessment Programme. BMJ Open 2017 Mar 20;7(3):e015276-2016-015276.
Sackett DL. Evidence-based medicine how to practice and teach EBM.: WB Saunders Company; 1997.
Walsh M, Srinathan SK, McAuley DF, Mrkobrada M, Levine O, Ribic C, et al. The statistical significance of randomized controlled trial results is frequently fragile: a case for a Fragility Index. J Clin Epidemiol. 2014;67(6):622–8.
Hollis S, Campbell F. What is meant by intention to treat analysis? Survey of published randomised controlled trials. BMJ. 1999 Sep 11;319(7211):670–4.
Vickers AJ, Altman DG. Statistics notes: missing outcomes in randomised trials. BMJ. 2013 Jun 6;346:f3438.
Brueton VC, Tierney J, Stenning S, Harding S, Meredith S, Nazareth I, et al. Strategies to improve retention in randomised trials. The Cochrane Library 2013.
Robinson KA, Dinglas VD, Sukrithan V, Yalamanchilli R, Mendez-Tellez PA, Dennison-Himmelfarb C, et al. Updated systematic review identifies substantial number of retention strategies: using more strategies retains more study participants. J Clin Epidemiol. 2015;68(12):1481–7.
Smith CT, Hickey H, Clarke M, Blazeby J, Williamson P. The trials methodological research agenda: results from a priority setting exercise. Trials. 2014;15(1):32.
McKee M, Britton A, Black N, McPherson K, Sanderson C, Bain C. Interpreting the evidence: choosing between randomised and non-randomised studies. BMJ. 1999;319(7205):312–5.
Anglemyer A, Horvath HT, Bero L. Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials. The Cochrane Library 2014.
El Feky A, Gillies K, Gardner H, Fraser C, Treweek S. A protocol for a systematic review of non-randomised evaluations of strategies to increase participant retention to randomised controlled trials. Systematic reviews. 2018;7(1):30.
Moher D, Liberati A, Tetzlaff J, Altman DG, Prisma Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097.
Edwards P, Roberts I, Clarke M, DiGuiseppi C, Pratap S, Wentz R, et al. Increasing response rates to postal questionnaires. Overview of systematic methodology reviews 2007:23.
Sterne JA, Hernan MA, Reeves BC, Savovic J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ. 2016;355:i4919.
Guyatt GH, Oxman AD, Kunz R, Falck-Ytter Y, Vist GE, Liberati A, et al. Going from evidence to recommendations. BMJ. 2008 May 10;336(7652):1049–51.
Guyatt GH, Oxman AD, Vist G, Kunz R, Brozek J, Alonso-Coello P, et al. GRADE guidelines: 4. Rating the quality of evidence—study limitations (risk of bias). J Clin Epidemiol. 2011;64(4):407–15.
Guyatt GH, Oxman AD, Kunz R, Brozek J, Alonso-Coello P, Rind D, et al. GRADE guidelines 6. Rating the quality of evidence—imprecision. J Clin Epidemiol. 2011;64(12):1283–93.
Guyatt GH, Oxman AD, Kunz R, Woodcock J, Brozek J, Helfand M, et al. GRADE guidelines: 7. Rating the quality of evidence—inconsistency. J Clin Epidemiol. 2011;64(12):1294–302.
Guyatt GH, Oxman AD, Kunz R, Woodcock J, Brozek J, Helfand M, et al. GRADE guidelines: 8. Rating the quality of evidence—indirectness. J Clin Epidemiol. 2011;64(12):1303–10.
Guyatt GH, Oxman AD, Montori V, Vist G, Kunz R, Brozek J, et al. GRADE guidelines: 5. Rating the quality of evidence—publication bias. J Clin Epidemiol. 2011;64(12):1277–82.
Treweek S, Pitkethly M, Cook J, Fraser C, Mitchell E, Sullivan F, et al. Strategies to improve recruitment to randomised trials. Cochrane Database Syst Rev. 2018;2.
Atherton H, Oakeshott P, Aghaizu A, Hay P, Kerry S. Use of an online questionnaire for follow-up of young female students recruited to a randomised controlled trial of chlamydia screening. J Epidemiol Community Health. 2010 Jul;64(7):580–4.
Childs JD, Bowman JA, Wu SS, Butler AM, Andrade RL, Teyhen DS, et al. Incremental effects of telephone call center and healthcare utilization database use to improve follow-up rate in the prevention of low back pain in the military trial. US Army Medical Department Journal 2015.
Dormandy E, Brown K, Reid EP, Marteau TM. Towards socially inclusive research: an evaluation of telephone questionnaire administration in a multilingual population. BMC Med Res Methodol. 2008;8(1):2.
Johnson NA, Kypri K, Latter J, McElduff P, Attia J, Saitz R, et al. Effect of telephone follow-up on retention and balance in an alcohol intervention trial. Prev Med Rep. 2015;2:746–9.
Lall R, Mistry D, Bridle C, Lamb SE. Telephone interviews can be used to collect follow-up data subsequent to no response to postal questionnaires in clinical trials. J Clin Epidemiol. 2012 Jan;65(1):90–9.
Peterson JC, Pirraglia PA, Wells MT, Charlson ME. Attrition in longitudinal randomized controlled trials: home visits make a difference. BMC Med Res Methodol. 2012;12(1):178.
Bailey JV, Pavlou M, Copas A, McCarthy O, Carswell K, Rait G, et al. The Sexunzipped trial: optimizing the design of online randomized controlled trials. J Med Internet Res. 2013 Dec 11;15(12):e278.
Ulmer M, Robinaugh D, Friedberg JP, Lipsitz SR, Natarajan S. Usefulness of a run-in period to reduce drop-outs in a randomized controlled trial of a behavioral intervention. Contemp Clin Trials. 2008 Sep;29(5):705–10.
Hansen E, Fonager K, Freund KS, Lous J. The impact of non-responders on health and lifestyle outcomes in an intervention study. BMC research notes. 2014;7(1):632.
Varner C, McLeod S, Nahiddi N, Borgundvaag B. Text messaging research participants as a follow-up strategy to decrease emergency department study attrition. CJEM. 2018 Jan;20(1):148–53.
Brealey SD, Atwell C, Bryan S, Coulton S, Cox H, Cross B, et al. Improving response rates using a monetary incentive for patient completion of questionnaires: an observational study. BMC Med Res Methodol. 2007;7(1):12.
Rodgers M, Meisel Z, Wiebe D, Crits-Christoph P, Rhodes KV. Wireless participant incentives using reloadable bank cards to increase clinical trial retention with abused women drinkers: a natural experiment. J Interpers Violence. 2016;0886260516662849.
Ezell JM, Saltzgaber J, Peterson E, Joseph CL. Reconnecting with urban youth enrolled in a randomized controlled trial and overdue for a 12-month follow-up survey. Clinical Trials. 2013;10(5):775–82.
Sellers CJ, Lee H, Chasela C, Kayira D, Soko A, Mofolo I, et al. Reducing lost to follow-up in a large clinical trial of prevention of mother-to-child transmission of HIV: the Breastfeeding, Antiretrovirals and Nutrition study experience. Clinical trials. 2015;12(2):156–65.
Varner C, McLeod S, Nahiddi N, Borgundvaag B. Text messaging research participants as a follow-up strategy to decrease emergency department study attrition. Canadian journal of emergency medicine. 2018;20(1):148–53.
Edwards P, Roberts I, Sandercock P, Frost C. Follow-up by mail in clinical trials: does questionnaire length matter? Control Clin Trials. 2004 Feb;25(1):31–52.
Ronckers C, Land C, Hayes R, Verduijn P, van Leeuwen F. Factors impacting questionnaire response in a Dutch retrospective cohort study. Ann Epidemiol. 2004 Jan;14(1):66–72.
Tai SS, Nazareth I, Haines A, Jowett C. A randomized trial of the impact of telephone and recorded delivery reminders on the response rate to research questionnaires. J Public Health. 1997;19(2):219–21.
May AM, Adema LE, Romaguera D, Vergnaud A, Agudo A, Ekelund U, et al. Determinants of non-response to a second assessment of lifestyle factors and body weight in the EPIC-PANACEA study. BMC Med Res Methodol. 2012;12(1):148.
Keding A, Brabyn S, MacPherson H, Richmond SJ, Torgerson DJ. Text message reminders to improve questionnaire response rates. J Clin Epidemiol. 2016 Nov;79:90–5.
Clark L, Ronaldson S, Dyson L, Hewitt C, Torgerson D, Adamson J. Electronic prompts significantly increase response rates to postal questionnaires: a randomized trial within a randomized trial and meta-analysis. J Clin Epidemiol. 2015;68(12):1446–50.
Kearney A, Daykin A, Shaw AR, Lane AJ, Blazeby JM, Clarke M, et al. Identifying research priorities for effective retention strategies in clinical trials. Trials. 2017;18(1):406.
Treweek S, Bevan S, Bower P, Campbell M, Christie J, Clarke M, et al. Trial Forge Guidance 1: what is a Study Within A Trial (SWAT)? Trials. 2018;19(1):139.