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Jonathan Cook

Jonathan Cook is an Associate Professor based at the Centre for Statistics in Medicine within the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS) at the University of Oxford. His main research interest is in the design, conduct, analysis and reporting of randomised controlled trials (particularly surgical trials). Specific areas of interest include specification of the target difference in the sample size calculation, addressing interventional expertise, and methods for improving recruitment. He also has extensive experience in systematic reviews of randomised controlled trials and diagnostic research. He has collaborated on numerous projects including randomised trials, observational and diagnostic studies, methodological projects and systematic reviews in a variety of clinical areas (anaesthesia, cardiovascular research, obstetrics and gynaecology, ophthalmology, orthopaedics, primary care, general surgery and urology amongst others). He is a Lead Statistician in Oxford Clinical Trials Research Unit (OCTRU) and is a Deputy Director of the Surgical Intervention Trials Unit (SITU).

Jonathan graduated from the University of Aberdeen with a BSc in Statistics. Following this he undertook a PhD on the statistical assessment of learning curve effects in randomised controlled trials. Subsequently, he worked at the Health Services Research Unit, University of Aberdeen as a Statistician. In August 2007, he started a MRC UK Fellowship focusing upon methodology related the design, conduct and analysis of surgical randomised trials. In 2012, he was awarded a MRC UK Methodology Fellowship focusing upon expertise-based trial designs and in August that year became a Senior Research Fellow. He joined the Centre for Statistics in Medicine in 2013 initially on a secondment during which he was appointed to a University Lectureship in the NDORMS, University of Oxford.

Jonathan holds a number of external responsibilities. These include serving on and chairing Data Monitoring and Steering committee for a number of clinical trials, being a Deputy Editor of Clinical Trials, and a statistical Editor for the British Journal of Surgery. He has over 150 fulltext publications including more than 50 as first or senior author.



Select Key publications

Cook JA, Julious SA, Sones W, Hampson LV, Hewitt C, Berlin JA, Ashby D,  Emsley R, Fergusson DA, Walters SJ, Wilson ECF, MacLennan G, Stallard N, Rothwell JC, Bland M, Brown L, Ramsay CR, Cook A, Armstrong D, Altman D, Vale LD.  DELTA2 guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial. BMJ 2018; 363. doi:


Cook JA, McCulloch P, Blazeby J, Beard D, Marinac-Dabic D, Sedrakyan A on behalf of the IDEAL group. IDEAL framework for surgical innovation: randomised controlled trials in the Assessment stage and evaluations in the Long term stage. BMJ 2013;346:f2820


Rombach I Knight R, Peckham N Stokes JR, Cook JA. Current practice in analysing and reporting binary outcome data – a review of randomised controlled trial report. BMC Medicine 18:147, 2020


Beard DJ, Campbell MK, Blazeby J, Carr AJ, Weijer C, Cuthbertson BH, Buchbinder R, Pinkney T, Bishop FL, Pugh J, Cousins S, Harris I, Lohmander LS, Blencowe N, Gillies K, Probst P, Brennan C, Farrar-Hockley D, Cook A, Savulescu J, Huxtable R, Rangan A, Tracey I, Brocklehurst P, Ferreira ML, Nicholl J, Reeves BC, Hamdy F, Rowley SCS, Cook JA. Considerations and Methods for Placebo Controls in Surgical Trials: State of the Art Review and ASPIRE Guidance. The Lancet 2020; 395: 828–38.

Copsey B, Thompson J, Vadher K, Ali U, Dutton S, Fitzpatrick R, Lamb SE, Cook JA. Sample size calculations are poorly conducted and reported in many randomised trials of hip and knee osteoarthritis: results of a systematic review. Journal of Clinical Epidemiology 2018