Choosing covariates in the analysis of cluster randomised trials. 
 
NB The closing date for applications is Friday 24th April 2009.

A graduate with experience and interest in medical statistics is required for 
this project based at the Centre for Health Sciences, Barts and The London 
School of Medicine and Dentistry, Queen Mary, University of London. 

Cluster randomised trials are increasingly popular. A gap in knowledge in 
relation to such trials is determining which covariates to include in the trial 
analysis. In trials in which individuals are randomised, increases in power and 
reductions in bias arise if variables correlated with outcomes, such as
levels of outcome collected at baseline, are introduced into analyses. In
cluster 
randomised trials covariates can occur at two levels, the cluster and the 
individual level, and there may be complicated relationships between 
covariates at different levels. There has been a small amount of work in this 
area but a comprehensive review is needed, particularly for non-continuous 
and non-normally distributed outcomes. 

The aim of this project is to review existing knowledge and practice in
relation to choosing covariates in cluster randomised trials and to develop 
recommendations for choosing covariates to enter into analyses of cluster 
randomised trials. The project will involve systematically reviewing 
methodological literature and empirical trial reports, analysis of data from 
empirical trials and simulation. 

The Centre has over 15 years’ experience in conducting trials and was rated 
fourth in the UK in health services research in the 2008 Research Assessment 
Exercise. The successful applicant will be based within the Pragmatic Clinical 
Trials Unit located within the Centre and will have extensive training 
opportunities both in research and statistical methods as appropriate. The 
Centre currently hosts 14 PhD students across of range of disciplines within 
community health sciences. 

For an informal discussion please contact the lead project supervisor: 
Dr S Bremner Tel: 020 7882 2547 Email: [log in to unmask] or 
Professor S Eldridge Tel: 020 7882 2519 Email: [log in to unmask] 

Start Date
October 2009

Entrance Requirement
You must have at least an upper second class honours degree, or a lower
second class honours degree plus a master’s degree in a relevant discipline.

Funding Notes
This three-year studentship is funded by the Medical Research Council and
comes with a tax free stipend of £15,510 per annum. This studentship is open
to UK Nationals, EEA/Swiss migrant workers and non UK nationals with indefinite 
leave to remain in the UK who all have three years ordinary residence in the 
UK prior to the start of the studentship.

To apply, please download the School of Medicine & Dentistry application form 
from our website: http://www.qmul.ac.uk/postgraduate/apply/index.html 
and return to the Admissions Office - email: [log in to unmask] 
Please note that we accept postal and electronic applications. 
Referees may email references directly to [log in to unmask]