• Health Care Assessment
• Delivery of Care
• Quality Assurance
• Research Tools
  • Study Design
  • Study Conduct
  • Outcome Measures
  • Review and Dissemination

Study Design

Sample Size calculator for cluster randomised trials

A sample size calculator for cluster randomised trials is obtainable from the link below. This is a self-extracting program.

NB// If you are experiencing any difficulties downloading the calculator please try using and alternative browser to download or right click on the link and choose 'save as' to download it manually to your own computer.  

• http://www.abdn.ac.uk/hsru/sampsize/ssc.exe

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

• https://www.abdn.ac.uk/hsru/documents/calculationmanual.pdf

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 Med2004;34:113-125.

If you have any queries about the calculator, please contact Graeme MacLennan (g.maclennan@abdn.ac.uk).

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.

• Implementation studies: Spreadsheet
• Implementation studies: References
• Surgical studies: 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.

• Contamination flowchart