Research Tools

Projects undertaken by the Unit have contributed to the development of many different research tools for both researchers and users of research. 

Sample Size calculator for cluster randomised trials

Version 2 of the sample size calculator is in development. 
Please click here for a beta version.  See also this document.

The instruction manual for this program can be downloaded as a pdf file at the link below.  

A further description of the calculator can be found in Campbell MK, Thomson S, Ramsay CR, MacLennan GS, Grimshaw JM. Sample size calculator for cluster randomised trials. Comput Biol Med 2004;34:113-125.

If you have any queries about the calculator, please contact Jemma Hudson (



In collaboration with colleagues at other Universities we have developed PRECIS-2, which is a tool to help trialists match their trial design decisions to the needs of the intended users of the trial results. PRECIS-2 has nine domains—eligibility criteria, recruitment, setting, organisation, flexibility (delivery), flexibility (adherence), follow-up, primary outcome, and primary analysis—scored from 1 (very explanatory design approach) to 5 (very pragmatic design approach) to facilitate domain discussion and consensus.


A website to support the use of the tool is available at


A description of PRECIS-2 can be found in Loudon K, Treweek S, Sullivan F, Donnan P, Thorpe KE, Zwarenstein M. The PRECIS-2 tool: designing trials that are fit for purpose. BMJ 2015;350:h2147 (


If you have any queries about the calculator, please contact Shaun Treweek (




Database of intra-correlation coefficients (ICCs)

A downloadable excel spreadsheet contains a list of intra-correlation coefficient calculated from a number of different interventions and settings. Also downloadable, is a list of references for the data contained in the spreadsheet.


Contamination in randomised trials

A flowchart was developed by the HTA Contamination in trials project to aid the decision on when a cluster randomised controlled trial might be preferred to a patient randomised controlled trial when contamination of controls are suspected.

Trial Protocol Tool

The Practihc collaboration developed a Trial Protocol Tool that supports the production of a high quality research protocol.  It provides a checklist of issues that should be considered when writing a protocol.  A paper describing the tool is available here.

Tool for conducting and managing RCTs

The SUPPORT project developed a Trial Management Tool to help trialists conduct and manage pragmatic randomised controlled trials (RCT).


The DAMOCLES study formulated a list of considerations that would be valuable for a Data Monitoring Committee (DMC) to address at the start of a trial which were developed into a charter.

Beliefs about surgery questionnaire

The REFLUX Study developed and validated a questionnaire for measuring patients Beliefs about surgery.

HSRU offer a 24-hour, seven day telephone randomisation service and/or randomisation over the Web.  For further information, click here.