Biostatistics photoThe biostatistics research team have expertise in methods for test evaluation, cluster and stepped-wedge studies, meta-analysis (including multivariate and panoramic meta-analysis), multi-parameter evidence synthesis, simulation, prognostic modelling and survival analysis. The team are involved in both methodological research and in primary studies applying statistical methods to answer clinical questions.

Theme Lead

Professor Jon DeeksProfessor Jon Deeks

Theme Lead

Professor of Biostatistics
Deputy Director

Institute of Applied Health Research

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About the research

The biostatistics team have a variety of research interests. The team have internationally renowned expertise in test evaluation and cluster RCTs. For more information on our work in test evaluation please see the TAP webpage.  

A key theme of the biostatistics group is methods for cluster RCTs and stepped-wedge studies, led by Professor Karla Hemming. Stepped-wedge cluster randomised trials (SW-CRT) are a relatively new study design, particularly applicable to interventions which are rolled out across centres over time. SW-CRT is necessary in various situations, such as those in which one cannot withhold the intervention from a control group for the full duration of the study, but it is possible to stagger the trial roll-out.

The team are involved in many primary studies, collaborating with colleagues in the institute and further afield.

The biostatistics team teach at undergraduate and post-graduate level and coordinate a number of modules across programmes. The teaching of the biostatistics team is led by Dr Alice Sitch.

The team provide CPD opportunities with regular workshops on cluster RCTs and test evaluation. The team are also developing a suite of CPD courses ranging from an introduction to statistical concepts to advanced modelling. 

Part of the umbrella group of BESTEAM, the Biostatistics group are also linked to the Evidence Synthesis group.

Meet the Team

The Biostatistics group are part of BESTEAM.

View the BESTEAM staff list.

Current projects

Methods research

  • NIHR Senior Research Fellowship held by Professor Karla Hemming:  Improving the evidence base of healthcare policy interventions through the stepped-wedge cluster randomised trial using mixed methodologies.

Karla's work has led to the development of:

  1. A web app to enable decisions to be made regarding the design of stepped-wedge trials - in particular, sample size calculations. This app receives over 100 hour’s access per month by trial designers.
  2. Improvements to the design of specific trials, saving funder (including UK taxpayer) resources, and contributing to more informative outcomes.
  • Miss Christina Easter is currently completing a PhD titled “Risk of bias in stepped wedge cluster randomised trials”. The objectives of the PhD are to; identify how to effectively adjust for underlying temporal trends at the analysis stage; identify whether published SW-CRTS are at risk of selection biases; identify the determinants and barriers to selection biases and; develop a tool to describe the risk of bias in a SW-CRT.

Primary Research

  • The Research Design Service (RDS) provides expert advice for those developing grant application specifically for NIHR programmes. Christina Easter is a statistical advisor for the RDS and provides statistical support for those who require it, namely assessing sample size calculations, general study design support and methods for statistical analysis. 
  • The NIHR Applied Research Collaborations (ARC) West Midlands is a five year initiative funded by the National Institute of Health research with matched funds provided by local health and social services. Their mission is to create lasting and effective partnerships across health and social care organisations, and universities (Birmingham, Keele and Warwick) in order to improve care services across the West Midlands. Laura Quinn works in the cross-cutting theme of research methodology and informatics splitting her time between working on methodological research and providing statistical support to research themes across the ARC. 
  • British Society of Urogynaecology (BSUG) data analyses: assessing the treatment procedures for urinary incontinence. This is a retrospective study primarily assessing four types of treatments for urinary incontinence on global impression of improvement for incontinence whilst accounting for important prognostic factors. 
  • Sedation AND Weaning in CHildren (SANDWICH) study aims to determine if a protocol-based intervention, incorporating co-ordinated care with greater nursing involvement to managing sedation and weaning ventilation, can reduce the duration of invasive mechanical ventilation (IMV) and is cost effective compared with usual care in children in PICUs. This is a multi-centred stepped wedge study conducted in the UK. (ISRCTN 16998143).
  • The effectiveness and cost-effectiveness of Assets-based feeding help Before and After birth (ABA) for improving breastfeeding initiation and continuation. NIHR Public Health Research.
  • FUEL study: An evaluation of the implementation of national school food standards in secondary schools and their impact on the school food environment and pupil intake of free sugars: a mixed methods study. NIHR Public Health Research.  
  • The impact of specialist led integrated care on guideline adherence and outcomes in COPD. Astra Zeneca Investigator Initiated study.
  • BreatheWell: Global-COPD group—Improving the diagnosis, management and prognosis of COPD patients in low and middle income countries. NIHR Global Health Research.
  • Assets-based feeding help Before and After birth (ABA): feasibility study for improving breastfeeding initiation and continuation. NIHR Public Health Research.
  • Birmingham Lung Improvement StudieS (BLISS): Improving the lung health of patients through population research. NIHR Programme Grant for Applied Health Research.

Key publications

Methods research

Girling AJ, Hemming K. Statistical efficiency and optimal design for stepped cluster studies under linear mixed effects models. Stat Med. 2016 Jun 15;35(13):2149-66. doi: 10.1002/sim.6850. Epub 2016 Jan 7. PubMed PMID: 26748662; PubMed Central PMCID: PMC4949721.

Martin JT, Hemming K, Girling A. The impact of varying cluster size in cross-sectional stepped-wedge cluster randomised trials. BMC Med Res Methodol. 2019 Jun 14;19(1):123. doi: 10.1186/s12874-019-0760-6. PubMed PMID: 31200640; PubMed Central PMCID: PMC6570871.

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 Nov 9;363:k1614. doi: 10.1136/bmj.k1614. PubMed PMID: 30413417; PubMed Central PMCID: PMC6225589.

Hemming K, Taljaard M, Marshall T, Goldstein CE, Weijer C. Stepped-wedge trials should be classified as research for the purpose of ethical review. Clin Trials. 2019 Dec;16(6):580-588. doi: 10.1177/1740774519873322. PubMed PMID: 31818147.

Hemming K, Carroll K, Thompson J, Forbes A, Taljaard M; SW-CRT Review Group. Quality of stepped-wedge trial reporting can be reliably assessed using an updated CONSORT: crowd-sourcing systematic review. J Clin Epidemiol. 2019 Mar;107:77-88. doi: 10.1016/j.jclinepi.2018.11.017. Epub 2018 Nov 28. Review. PubMed PMID: 30500405. 


Hemming K, Kasza J, Hooper R, Forbes A, Taljaard M. A tutorial on sample size calculation for multiple-period cluster randomized parallel, cross-over and stepped-wedge trials using the Shiny CRT Calculator. Int J Epidemiol. 2020 Feb 22.pii: dyz237. doi: 10.1093/ije/dyz237. 

Primary Research

Mason F, Farley A, Pallan M, Sitch A, Easter C, Daley A J. Effectiveness of a brief behavioural intervention to prevent weight gain over the Christmas holiday period: randomised controlled trial BMJ 2018; 363

Kumarendran B, O’Reilly MW, Manolopoulos KN, Toulis KA, Gokhale KM, Sitch AJ, Wijeyaratne CN, Coomarasamy A, Arlt W, Nirantharakumar K. Polycystic ovary syndrome, androgen excess, and the risk of nonalcoholic fatty liver disease in women: A longitudinal study based on a United Kingdom primary care database. PLoS Med. 2018 Mar 28;15(3):e1002542. doi: 10.1371/journal.pmed.1002542. eCollection 2018 Mar. PubMed PMID: 29590099; PubMed Central PMCID: PMC5873722.

Jordan RE, Adab P, Sitch A, Enocson A, Blissett D, Jowett S, Marsh J, Riley RD, Miller MR, Cooper BG, Turner AM, Jolly K, Ayres JG, Haroon S, Stockley R, Greenfield S, Siebert S, Daley AJ, Cheng KK, Fitzmaurice D. Targeted case finding for chronic obstructive pulmonary disease versus routine practice in primary care (TargetCOPD): a cluster-randomised controlled trial. Lancet Respir Med. 2016 Sep;4(9):720730. doi: 10.1016/S2213-2600(16)30149-7. Epub 2016 Jul 19. PubMed PMID: 27444687.

Li B, Pallan M, Liu WJ, Hemming K, Frew E, Lin R, Liu W, Martin J, Zanganeh M, Hurley K, Cheng KK, Adab P. The CHIRPY DRAGON intervention in preventing obesity in Chinese primary-school--aged children: A cluster-randomised controlled trial. PLoS Med. 2019 Nov 26;16(11):e1002971. doi: 10.1371/journal.pmed.1002971. eCollection 2019 Nov. PubMed PMID: 31770371; PubMed Central PMCID: PMC6879117.

Roshandel G, Khoshnia M, Poustchi H, Hemming K, Kamangar F, Gharavi A, Ostovaneh MR, Nateghi A, Majed M, Navabakhsh B, Merat S, Pourshams A, Nalini M, Malekzadeh F, Sadeghi M, Mohammadifard N, Sarrafzadegan N, Naemi-Tabiei M, Fazel A, Brennan P, Etemadi A, Boffetta P, Thomas N, Marshall T, Cheng KK, Malekzadeh R. Effectiveness of polypill for primary and secondary prevention of cardiovascular diseases (PolyIran): a pragmatic, cluster-randomised trial. Lancet. 2019 Aug 24;394(10199):672-683. doi: 10.1016/S0140-6736(19)31791-X.PubMed PMID: 31448738. 

Adab P, Pallan MJ, Lancashire ER, Hemming K, Frew E, Barrett T, Bhopal R, Cade JE, Canaway A, Clarke JL, Daley A, Deeks JJ, Duda JL, Ekelund U, Gill P, Griffin T, McGee E, Hurley K, Martin J, Parry J, Passmore S, Cheng KK. Effectiveness of a childhood obesity prevention programme delivered through schools, targeting 6 and 7 year olds: cluster randomised controlled trial (WAVES study). BMJ. 2018 Feb 7;360:k211. doi: 10.1136/bmj.k211. Erratum in: BMJ. 2018 May 2;361:k1954. PubMed PMID: 29437667; PubMed Central PMCID: PMC5792961.


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