Pragmatic Clinical Trials Unit

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Our Methodological Publications

PCTU staff have written a number of methodological papers that can be located in this section, organised by year of published date. 

If you would like more information about how to collaborate with PCTU on a future study, please check here.


  • Jolly K, Sidhu M, PSM COPD Group, Bower P, Madurasinghe V, MRC START Group (2019). Improving recruitment to a study of telehealth management for COPD: a cluster randomised controlled 'study within a trial' (SWAT) of a multimedia information resource. Trials vol. 20, (1) 1186/s13063-019-3496-z  

    Leyrat C, Caille A, Eldridge S, Kerry S, Dechartres A, Giraudeau B(2019). Intervention effect estimates in cluster randomized versus individually randomized trials: a meta-epidemiological study. Int J Epidemiol vol. 48, (2) 609-619. 10.1093/ije/dyy229   

  • ELDRIDGE SM, Kristunas CA, Hemming K, Eborall H, Gray LJ (2019). The current use of feasibility studies in the assessment of feasibility for stepped-wedge cluster randomised trials: a systematic review. BMC Medical Research Methodology vol. 19, (1)10.1186/s12874-019-0658-3  

  • Karla Hemming, Kelly Carroll, Jennifer Thompson, Andrew Forbes, Monica Taljaard, The SW-CRT Review Group. Quality of stepped-wedge trial reporting can be reliably assessed using an updated CONSORT: crowd-sourcing systematic review. Journal of clinical epidemiology. 2019; 107:77-88

  • Hooper R, Copas A (2019). Stepped wedge trials with continuous recruitment require new ways of thinking. Journal of Clinical Epidemiology 1016/j.jclinepi.2019.05.037

  • Kasza J, Hemming K, Hooper R, Matthews J, Forbes AB (2019). Impact of non-uniform correlation structure on sample size and power in multiple-period cluster randomised trials. Stat Methods Med Res vol. 28, (3) 703-716. 1177/0962280217734981

  • Hooper R, Knowles C (2019). Improving the efficiency of individually randomized clinical trials by staggering the introduction of the intervention. Stat Med vol. 38, (1) 44-52. 1002/sim.7959

  • Tsui M, Rehal S, Jairath V, Kahan BC (2019). Most non-inferiority trials were not designed to preserve active comparator treatment effects. J Clin Epidemiol vol. 110, 82-89. 1016/j.jclinepi.2019.03.003

  • ALLOTEY JOE, MARLIN N (2019). Well‐conducted randomisation will improve balance and reliability of treatment estimates. Randomised controlled trials: random acts of allocation. BJOG: An International Journal of Obstetrics and Gynaecology, 1111/1471-0528.15496


  • Amundsen PA, Evans DW, Rajendran D, Bright P, Bjorkli T, Eldridge S, Buchbinder R, Underwood M, Froud R. Inclusion and exclusion criteria used in non-specific low back pain trials: a review of randomised controlled trials published between 2006 and 2012. BMC Musculoskelet Disord 2018;19:113.
  • Campbell MJ, Lancaster GA, Eldridge SM. A randomised controlled trial is not a pilot trial simply because it uses a surrogate endpoint. Pilot Feasibility Stud 2018;4:130.
  • Hemming K, Taljaard M, Forbes G, Eldridge SM, Weijer C. Ethical implications of excessive cluster sizes in cluster randomised trials. BMJ Qual Saf 2018;
  • Hemming K, Taljaard M, McKenzie JE, Hooper R, Copas A, Thompson JA, Dixon-Woods M, Aldcroft A, Doussau A, Grayling M, Kristunas C, Goldstein CE, Campbell MK, Girling A, Eldridge S, Campbell MJ, Lilford RJ, Weijer C, Forbes AB, Grimshaw JM. Reporting of stepped wedge cluster randomised trials: extension of the CONSORT 2010 statement with explanation and elaboration. BMJ 2018;363:k1614.
  • Hooper R, Forbes A, Hemming K, Takeda A, Beresford L. Analysis of cluster randomised trials with an assessment of outcome at baseline. BMJ 2018;360:k1121.
  • Hooper R, Knowles C. Improving the efficiency of individually randomized clinical trials by staggering the introduction of the intervention. Stat Med 2018;
  • Kahan BC, Morris TP, Harris E, Pearse R, Hooper R, Eldridge S. Re-randomization increased recruitment and provided similar treatment estimates as parallel designs in trials of febrile neutropenia. J Clin Epidemiol 2018;
  • Keerie C, Tuck C, Milne G, Eldridge S, Wright N, Lewis SC. Data sharing in clinical trials - practical guidance on anonymising trial datasets. Trials 2018;19:25.
  • Leyrat C, Morgan KE, Leurent B, Kahan BC. Cluster randomized trials with a small number of clusters: which analyses should be used? Int J Epidemiol 2018;47:321-331.
  • Parker A, Knapp P, Treweek S, Madhurasinghe V, Littleford R, Gallant S, Sullivan F, Schembri S, Rick J, Graffy J, Collier DJ, Eldridge S, Kennedy A, Bower P. The effect of optimised patient information materials on recruitment in a lung cancer screening trial: an embedded randomised recruitment trial. Trials 2018;19:503.
  • Taljaard M, Weijer C, Grimshaw JM, Ali A, Brehaut JC, Campbell MK, Carroll K, Edwards S, Eldridge S, Forrest CB, Giraudeau B, Goldstein CE, Graham ID, Hemming K, Hey SP, Horn AR, Jairath V, Klassen TP, London AJ, Marlin S, Marshall JC, McIntyre L, McKenzie JE, Nicholls SG, Alison Paprica P, Zwarenstein M, Fergusson DA. Developing a framework for the ethical design and conduct of pragmatic trials in healthcare: a mixed methods research protocol. Trials 2018;19:525.
  • Yelland LN, Kahan BC, Dent E, Lee KJ, Voysey M, Forbes AB, Cook JA. Prevalence and reporting of recruitment, randomisation and treatment errors in clinical trials: A systematic review. Clin Trials 2018;1740774518761627.


  • Al Wattar BH, Dodds J, Placzek A, Spyreli E, Higgins S, Moore A, Hooper R, Beresford L, Roseboom TJ, Bes-Rastrollo M, Hitman G, Khan KS, Thangaratinam S. Mediterranean diet based intervention in pregnancy to improve maternal and fetal outcomes: Methodological challenges and lessons learned from the multicentre ESTEEM study. Contemporary Clinical Trials Communications 2017;6:72-77.
  • Chan CL, Leyrat C, Eldridge SM. Quality of reporting of pilot and feasibility cluster randomised trials: a systematic review. BMJ Open 2017;7:e016970.
  • Clayton GL, Smith IL, Higgins JPT, Mihaylova B, Thorpe B, Cicero R, Lokuge K, Forman JR, Tierney JF, White IR, Sharples LD, Jones HE. The INVEST project: investigating the use of evidence synthesis in the design and analysis of clinical trials. Trials 2017;18:219.
  • Forbes G, Loudon K, Treweek S, Taylor SJC, Eldridge S. Understanding the applicability of results from primary care trials: lessons learned from applying PRECIS-2. J Clin Epidemiol 2017;90:119-126.
  • Froud R, Rajendran D, Patel S, Bright P, Bjorkli T, Eldridge S, Buchbinder R, Underwood M. The Power of Low Back Pain Trials: A Systematic Review of Power, Sample Size, and Reporting of Sample Size Calculations Over Time, in Trials Published Between 1980 and 2012. Spine 2017;42:E680-E686.
  • Hemming K, Eldridge S, Forbes G, Weijer C, Taljaard M. How to design efficient cluster randomised trials. BMJ 2017;358:j3064.
  • Hounsome N, Fitzsimmons D, Phillips C, Patel A. Developing core economic outcome sets for asthma studies: a protocol for a systematic review. BMJ Open 2017;7:e017054.
  • Kahan BC, Feagan B, Jairath V. A comparison of approaches for adjudicating outcomes in clinical trials. Trials 2017;18:266.
  • Kasza J, Hemming K, Hooper R, Matthews J, Forbes AB, Outcomes ACf, Resource Evaluation C. Impact of non-uniform correlation structure on sample size and power in multiple-period cluster randomised trials. Stat Methods Med Res 2017;962280217734981.
  • Madurasinghe VW. Sequence balance minimisation: minimising with unequal treatment allocations. Trials 2017;18:207.
  • Morgan KE, Forbes AB, Keogh RH, Jairath V, Kahan BC. Choosing appropriate analysis methods for cluster randomised cross-over trials with a binary outcome. Stat Med 2017;36:318-333.
  • Pinnock H, Barwick M, Carpenter CR, Eldridge S, Grandes G, Griffiths CJ, Rycroft-Malone J, Meissner P, Murray E, Patel A, Sheikh A, Taylor SJ. Standards for Reporting Implementation Studies (StaRI): explanation and elaboration document. BMJ Open 2017;7:e013318.
  • Rogozinska E, Marlin N, Thangaratinam S, Khan KS, Zamora J. Meta-analysis using individual participant data from randomised trials: opportunities and limitations created by access to raw data. Evid Based Med 2017;22:157-162.
  • Rogozinska E, Marlin N, Yang F, Dodd JM, Guelfi K, Teede H, Surita F, Jensen DM, Geiker NRW, Astrup A, Yeo S, Kinnunen TI, Stafne SN, Cecatti JG, Bogaerts A, Hauner H, Mol BW, Scudeller TT, Vinter CA, Renault KM, Devlieger R, Thangaratinam S, Khan KS. Variations in reporting of outcomes in randomized trials on diet and physical activity in pregnancy: A systematic review. J Obstet Gynaecol Res 2017;43:1101-1110.
  • van der Velden JM, Verkooijen HM, Young-Afat DA, Burbach JP, van Vulpen M, Relton C, van Gils CH, May AM, Groenwold RH. The cohort multiple randomized controlled trial design: a valid and efficient alternative to pragmatic trials? Int J Epidemiol 2017;46:96-102.
  • Viksveen P, Relton C, Nicholl J. Benefits and challenges of using the cohort multiple randomised controlled trial design for testing an intervention for depression. Trials 2017;18:308.


  • Arnup SJ, Forbes AB, Kahan BC, Morgan KE, McKenzie JE. The quality of reporting in cluster randomised crossover trials: proposal for reporting items and an assessment of reporting quality. Trials 2016;17:575.
  • Arnup SJ, Forbes AB, Kahan BC, Morgan KE, McKenzie JE. Appropriate statistical methods were infrequently used in cluster-randomized crossover trials. J Clin Epidemiol 2016;74:40-50.
  • Caille A, Kerry S, Tavernier E, Leyrat C, Eldridge S, Giraudeau B. Timeline cluster: a graphical tool to identify risk of bias in cluster randomised trials. BMJ 2016;354:i4291.
  • Cheong-See F, Allotey J, Marlin N, Mol BW, Schuit E, ter Riet G, Riley RD, Moons KGM, Khan KS, Thangaratinam S. Prediction models in obstetrics: understanding the treatment paradox and potential solutions to the threat it poses. BJOG 2016;123:1060-1064.
  • Eldridge SM, Chan CL, Campbell MJ, Bond CM, Hopewell S, Thabane L, Lancaster GA. CONSORT 2010 statement: extension to randomised pilot and feasibility trials. Pilot Feasibility Stud 2016;2:64.
  • Eldridge SM, Chan CL, Campbell MJ, Bond CM, Hopewell S, Thabane L, Lancaster GA. CONSORT 2010 statement: extension to randomised pilot and feasibility trials. BMJ 2016;355:
  • Eldridge SM, Costelloe CE, Kahan BC, Lancaster GA, Kerry SM. How big should the pilot study for my cluster randomised trial be? Statistical Methods in Medical Research 2016;25:1039-1056.
  • Eldridge SM, Lancaster GA, Campbell MJ, Thabane L, Hopewell S, Coleman CL, Bond CM. Defining Feasibility and Pilot Studies in Preparation for Randomised Controlled Trials: Development of a Conceptual Framework. PLoS One 2016;11:e0150205.
  • Froud R, Patel S, Rajendran D, Bright P, Bjorkli T, Buchbinder R, Eldridge S, Underwood M. A Systematic Review of Outcome Measures Use, Analytical Approaches, Reporting Methods, and Publication Volume by Year in Low Back Pain Trials Published between 1980 and 2012: Respice, adspice, et prospice. PLoS One 2016;11:e0164573.
  • Hooper R, Teerenstra S, de Hoop E, Eldridge S. Sample size calculation for stepped wedge and other longitudinal cluster randomised trials. Stat Med 2016;35:4718-4728.
  • Kahan BC. Using re-randomization to increase the recruitment rate in clinical trials - an assessment of three clinical areas. Trials 2016;17:595.
  • Kahan BC, Dore CJ, Murphy MF, Jairath V. Bias was reduced in an open-label trial through the removal of subjective elements from the outcome definition. J Clin Epidemiol 2016;77:38-43.
  • Kahan BC, Forbes G, Ali Y, Jairath V, Bremner S, Harhay MO, Hooper R, Wright N, Eldridge SM, Leyrat C. Increased risk of type I errors in cluster randomised trials with small or medium numbers of clusters: a review, reanalysis, and simulation study. Trials 2016;17:438.
  • Kahan BC, Rushton H, Morris TP, Daniel RM. A comparison of methods to adjust for continuous covariates in the analysis of randomised trials. BMC Med Res Methodol 2016;16:42.
  • Lau R, Stevenson F, Ong BN, Dziedzic K, Treweek S, Eldridge S, Everitt H, Kennedy A, Qureshi N, Rogers A, Peacock R, Murray E. Achieving change in primary care--causes of the evidence to practice gap: systematic reviews of reviews. Implement Sci 2016;11:40.
  • Madurasinghe VW. Guidelines for reporting embedded recruitment trials. Trials 2016;17:27.
  • Russell J, Berney L, Stansfeld S, Lanz D, Kerry S, Chandola T, Bhui K. The role of qualitative research in adding value to a randomised controlled trial: lessons from a pilot study of a guided e-learning intervention for managers to improve employee wellbeing and reduce sickness absence. Trials 2016;17:396.
  • Stevens N, Edwards L, Balayah Z, Hooper R, Knowles C. Risk based survey evidence supports electronic informed consent as a recruitment method for UK clinical trials. Journal of Clinical Epidemiology 2016;77:134-136.
  • Thabane L, Hopewell S, Lancaster GA, Bond CM, Coleman CL, Campbell MJ, Eldridge SM. Erratum to: Methods and processes for development of a CONSORT extension for reporting pilot randomized controlled trials. Pilot Feasibility Stud 2016;2:35.


  • Anastasiadis E, Ahmed HU, Relton C, Emberton M. A novel randomised controlled trial design in prostate cancer. BJU Int 2015;116:6-8.
  • Froud R, Bjorkli T, Bright P, Rajendran D, Buchbinder R, Underwood M, Evans D, Eldridge S. The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression. BMC Musculoskelet Disord 2015;16:370.
  • Froud R, Ellard D, Patel S, Eldridge S, Underwood M. Primary outcome measure use in back pain trials may need radical reassessment. BMC Musculoskelet Disord 2015;16:88.
  • Hooper R, Bourke L. Cluster randomised trials with repeated cross sections: alternatives to parallel group designs. Bmj 2015;350:h2925.
  • Kahan BC, Forbes AB, Dore CJ, Morris TP. A re-randomisation design for clinical trials. BMC Med Res Methodol 2015;15:96.
  • Kahan BC, Harhay MO. Many multicenter trials had few events per center, requiring analysis via random-effects models or GEEs. J Clin Epidemiol 2015;68:1504-11.
  • Kahan BC, Rehal S, Cro S. Risk of selection bias in randomised trials. Trials 2015;16:405.
  • Kahan BC, Rehal S, Cro S. Blinded Outcome Assessment Was Infrequently Used and Poorly Reported in Open Trials. PLoS One 2015;10:e0131926.
  • Lau R, Stevenson F, Ong BN, Dziedzic K, Treweek S, Eldridge S, Everitt H, Kennedy A, Qureshi N, Rogers A, Peacock R, Murray E. Achieving change in primary care--effectiveness of strategies for improving implementation of complex interventions: systematic review of reviews. BMJ Open 2015;5:e009993.
  • Pinnock H, Epiphaniou E, Sheikh A, Griffiths C, Eldridge S, Craig P, Taylor SJ. Developing standards for reporting implementation studies of complex interventions (StaRI): a systematic review and e-Delphi. Implement Sci 2015;10:42.
  • Rutterford C, Copas A, Eldridge S. Methods for sample size determination in cluster randomized trials. Int J Epidemiol 2015;44:1051-67.
  • Rutterford C, Taljaard M, Dixon S, Copas A, Eldridge S. Reporting and methodological quality of sample size calculations in cluster randomized trials could be improved: a review. J Clin Epidemiol 2015;68:716-23.
  • Wright N, Ivers N, Eldridge S, Taljaard M, Bremner S. A review of the use of covariates in cluster randomized trials uncovers marked discrepancies between guidance and practice. J Clin Epidemiol 2015;68:603-9.


  • Ahmed HU, Berge V, Bottomley D, Cross W, Heer R, Kaplan R, Leslie T, Parker C, Relton C, Stephens R, Sydes MR, Turnbull L, van der Meulen J, Vickers A, Wilt T, Emberton M, Prostate Cancer RCTCG. Can we deliver randomized trials of focal therapy in prostate cancer? Nat Rev Clin Oncol 2014;11:482-91.
  • Alva M, Gray A, Mihaylova B, Clarke P. The effect of diabetes complications on health-related quality of life: the importance of longitudinal data to address patient heterogeneity. Health Econ 2014;23:487-500.
  • Arnup SJ, Forbes AB, Kahan BC, Morgan KE, McDonald S, McKenzie JE. The use of the cluster randomized crossover design in clinical trials: protocol for a systematic review. Syst Rev 2014;3:86.
  • Devine A, Taylor SJ, Spencer A, Diaz-Ordaz K, Eldridge S, Underwood M. The agreement between proxy and self-completed EQ-5D for care home residents was better for index scores than individual domains. J Clin Epidemiol 2014;67:1035-43.
  • Diaz-Ordaz K, Kenward MG, Cohen A, Coleman CL, Eldridge S. Are missing data adequately handled in cluster randomised trials? A systematic review and guidelines. Clin Trials 2014;11:590-600.
  • Hooper R, Bourke L. The dog-leg: an alternative to a cross-over design for pragmatic clinical trials in relatively stable populations. Int J Epidemiol 2014;43:930-6.
  • Kahan BC. Accounting for centre-effects in multicentre trials with a binary outcome - when, why, and how? BMC Med Res Methodol 2014;14:20.
  • Kahan BC, Cro S, Dore CJ, Bratton DJ, Rehal S, Maskell NA, Rahman N, Jairath V. Reducing bias in open-label trials where blinded outcome assessment is not feasible: strategies from two randomised trials. Trials 2014;15:456.
  • Kahan BC, Jairath V, Dore CJ, Morris TP. The risks and rewards of covariate adjustment in randomized trials: an assessment of 12 outcomes from 8 studies. Trials 2014;15:139.
  • Kahan BC, Morris TP. A note regarding 'random effects' - authors' response. Stat Med 2014;33:2878-9.
  • Lau R, Stevenson F, Ong BN, Dziedzic K, Eldridge S, Everitt H, Kennedy A, Kontopantelis E, Little P, Qureshi N, Rogers A, Treweek S, Peacock R, Murray E. Addressing the evidence to practice gap for complex interventions in primary care: a systematic review of reviews protocol. BMJ Open 2014;4:e005548.
  • Morris TP, Kahan BC, White IR. Choosing sensitivity analyses for randomised trials: principles. BMC Med Res Methodol 2014;14:11.
  • Rick J, Graffy J, Knapp P, Small N, Collier DJ, Eldridge S, Kennedy A, Salisbury C, Treweek S, Torgerson D, Wallace P, Madurasinghe V, Hughes-Morley A, Bower P. Systematic techniques for assisting recruitment to trials (START): study protocol for embedded, randomized controlled trials. Trials 2014;15:407.
  • Rogers A, Harris T, Victor C, Woodcock A, Limb E, Kerry S, Iliffe S, Whincup P, Ekelund U, Beighton C, Ussher M, Adams F, Cook DG. Which older people decline participation in a primary care trial of physical activity and why: insights from a mixed methods approach. BMC Geriatr 2014;14:46.
  • Weijer C, Taljaard M, Grimshaw JM, Edwards SJL, Eccles MP, Althabe F, Binik A, Brown JB, Boruch R, Brehaut JC, Chaudhry S, Donner A, Dubois-Flynn G, Eccles MP, Edwards S, Elbourne D, Eldridge S, Forster D, Gallo A, Kiefe C, Kimmelman J, Lin M, Loder E, Lohr L, McRae AD, Naughton ES, Polson RJ, Saginur R, Saxena A, Spence J, Taljaard M, White A, White G, Zwarenstein M. The Ottawa statement on the ethical design and conduct of cluster randomized trials: A short report. Research Ethics 2014;10:77-85.


  • Diaz-Ordaz K, Froud R, Sheehan B, Eldridge S. A systematic review of cluster randomised trials in residential facilities for older people suggests how to improve quality. BMC Med Res Methodol 2013;13:127.
  • Diaz-Ordaz K, Slowther AM, Potter R, Eldridge S. Consent processes in cluster-randomised trials in residential facilities for older adults: a systematic review of reporting practices and proposed guidelines. BMJ Open 2013;3:
  • Hooper R. Versatile sample-size calculation using simulation. Stata Journal 2013;13:21-38.
  • Hooper R, Diaz-Ordaz K, Takeda A, Khan K. Comparing diagnostic tests: trials in people with discordant test results. Stat Med 2013;32:2443-56.
  • Hooper R, Froud RJ, Bremner SA, Perera R, Eldridge S. Cascade diagrams for depicting complex interventions in randomised trials. BMJ 2013;347:f6681.
  • Kahan BC. Bias in randomised factorial trials. Stat Med 2013;32:4540-9.
  • Kahan BC, Morris TP. Adjusting for multiple prognostic factors in the analysis of randomised trials. BMC Med Res Methodol 2013;13:99.
  • Kahan BC, Morris TP. Assessing potential sources of clustering in individually randomised trials. BMC Med Res Methodol 2013;13:58.
  • Kahan BC, Morris TP. Analysis of multicentre trials with continuous outcomes: when and how should we account for centre effects? Stat Med 2013;32:1136-49.
  • Taljaard M, Weijer C, Grimshaw JM, Eccles MP. The Ottawa Statement on the ethical design and conduct of cluster randomised trials: precis for researchers and research ethics committees. BMJ 2013;346:f2838.


  • Bratton DJ, Williams HC, Kahan BC, Phillips PP, Nunn AJ. When inferiority meets non-inferiority: implications for interim analyses. Clin Trials 2012;9:605-9.
  • Choudhury Y, Hussain I, Parsons S, Rahman A, Eldridge S, Underwood M. Methodological challenges and approaches to improving response rates in population surveys in areas of extreme deprivation. Prim Health Care Res Dev 2012;13:211-8.
  • Eldridge S, Kerry S. A practical guide to cluster randomised trials in health services research. 2012 Wiley(Chichester)
  • Froud R, Eldridge S, Diaz Ordaz K, Marinho VC, Donner A. Quality of cluster randomized controlled trials in oral health: a systematic review of reports published between 2005 and 2009. Community Dent Oral Epidemiol 2012;40 Suppl 1:3-14.
  • Froud R, Underwood M, Carnes D, Eldridge S. Clinicians' perceptions of reporting methods for back pain trials: a qualitative study. Br J Gen Pract 2012;62:e151-9.
  • Froud R, Underwood M, Eldridge S. Improving the reporting and interpretation of clinical trial outcomes. Br J Gen Pract 2012;62:e729-31.
  • Kahan BC, Morris TP. Reporting and analysis of trials using stratified randomisation in leading medical journals: review and reanalysis. BMJ 2012;345:e5840.
  • Kahan BC, Morris TP. Improper analysis of trials randomised using stratified blocks or minimisation. Stat Med 2012;31:328-40.
  • Peacock JL, Sauzet O, Ewings SM, Kerry SM. Dichotomising continuous data while retaining statistical power using a distributional approach. Statistics in Medicine 2012;31:3089-3103.
  • Reininghaus U, Priebe S. Measuring patient-reported outcomes in psychosis: conceptual and methodological review. British Journal of Psychiatry 2012;201:262-267.
  • Teerenstra S, Eldridge S, Graff M, de Hoop E, Borm GF. A simple sample size formula for analysis of covariance in cluster randomized trials. Stat Med 2012;31:2169-78.
  • Weijer C, Grimshaw JM, Eccles MP, McRae AD, White A, Brehaut JC, Taljaard M. The Ottawa Statement on the Ethical Design and Conduct of Cluster Randomized Trials. PLoS Med 2012;9:e1001346.


  • Froud R, Eldridge S, Kovacs F, Breen A, Bolton J, Dunn K, Fritz J, Keller A, Kent P, Lauridsen HH, Ostelo R, Pincus T, van Tulder M, Vogel S, Underwood M. Reporting outcomes of back pain trials: a modified Delphi study. Eur J Pain 2011;15:1068-74.
  • Hounsome N, Orrell M, Edwards RT. EQ-5D as a quality of life measure in people with dementia and their carers: evidence and key issues. Value Health 2011;14:390-9.
  • Mihaylova B, Briggs A, O'Hagan A, Thompson SG. Review of statistical methods for analysing healthcare resources and costs. Health Econ 2011;20:897-916.
  • Nadeem NJ, Taylor SJ, Eldridge SM. Withdrawal of inhaled corticosteroids in individuals with COPD--a systematic review and comment on trial methodology. Respir Res 2011;12:107.


  • Eldridge S. Pragmatic trials in primary health care: what, when and how? Fam Pract 2010;27:591-2.
  • Lancaster GA, Campbell MJ, Eldridge S, Farrin A, Marchant M, Muller S, Perera R, Peters TJ, Prevost AT, Rait G. Trials in primary care: statistical issues in the design, conduct and evaluation of complex interventions. Stat Methods Med Res 2010;19:349-77.
  • Relton C, Torgerson D, O'Cathain A, Nicholl J. Rethinking pragmatic randomised controlled trials: introducing the "cohort multiple randomised controlled trial" design. BMJ 2010;340:c1066.


  • Eldridge S, Kerry S, Torgerson DJ. Bias in identifying and recruiting participants in cluster randomised trials: what can be done? BMJ 2009;339:
  • Eldridge SM, Ukoumunne OC, Carlin JB. The Intra-Cluster Correlation Coefficient in Cluster Randomized Trials: A Review of Definitions. International Statistical Review 2009;77:378-394.
  • Froud R, Eldridge S, Lall R, Underwood M. Estimating the number needed to treat from continuous outcomes in randomised controlled trials: methodological challenges and worked example using data from the UK Back Pain Exercise and Manipulation (BEAM) trial. BMC Med Res Methodol 2009;9:35.
  • Hooper R. The Bayesian interpretation of a P-value depends only weakly on statistical power in realistic situations. J Clin Epidemiol 2009;62:1242-7.


  • Eldridge S, Ashby D, Bennett C, Wakelin M, Feder G. Internal and external validity of cluster randomised trials: systematic review of recent trials. BMJ 2008;336:876-80.


  • Eldridge SM, Ashby D, Kerry S. Sample size for cluster randomized trials: effect of coefficient of variation of cluster size and analysis method. Int J Epidemiol 2006;35:1292-300.


  • Eldridge S, Spencer A, Cryer C, Parsons S, Underwood M, Feder G. Why modelling a complex intervention is an important precursor to trial design: lessons from studying an intervention to reduce falls-related injuries in older people. J Health Serv Res Policy 2005;10:133-42.
  • Eldridge SM, Ashby D, Feder GS. Informed patient consent to participation in cluster randomized trials: an empirical exploration of trials in primary care. Clin Trials 2005;2:91-8.
  • Kerry SM, Cappuccio FP, Emmett L, Plange-Rhule J, Eastwood JB. Reducing selection bias in a cluster randomized trial in West African villages. Clin Trials 2005;2:125-9.


  • Adams G, Gulliford MC, Ukoumunne OC, Eldridge S, Chinn S, Campbell MJ. Patterns of intra-cluster correlation from primary care research to inform study design and analysis. J Clin Epidemiol 2004;57:785-94.
  • Eldridge SM, Ashby D, Feder GS, Rudnicka AR, Ukoumunne OC. Lessons for cluster randomized trials in the twenty-first century: a systematic review of trials in primary care. Clin Trials 2004;1:80-90.
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