Cluster randomised trials randomise groups of individuals rather than individuals themselves to interventions. The groups might be communities, schools, workplaces, hospitals, or patients treated by a particular doctor. There are a number of reasons for the use of cluster trials as opposed to individually randomised trials. They may be the only available choice, as when a city is randomised to a mass intervention. Another reason is that the investigators may wish to reduce the risk of contamination (Box 1), or it may be more effective, more convenient or cheaper to deliver an intervention to a group rather than to an individual. For example, patients in the same education program will interact with each other and may learn better together than on their own, making a course more effective and economical than one‐on‐one tuition.
The full article is accessible to AMA members and paid subscribers. Login to read more or purchase a subscription now.
Please note: institutional and Research4Life access to the MJA is now provided through Wiley Online Library.
- 1. Campbell MJ. Walters SJ. How to design, analyse and report cluster randomized trials in medicine and health services research. Chichester: Wiley, 2014.
- 2. Donner A, Klar N. Design and analysis of cluster randomized trials in health research. London: Arnold, 2000.
- 3. Eldridge S, Kerry S. A practical guide to cluster randomized trials in health services research. Chichester: Wiley, 2012.
- 4. Hayes RJ, Moulton LH. Cluster randomized trials. Boca Raton: Chapman and Hall/CRC, 2009.
- 5. Campbell MJ. Challenges of cluster randomized trials. J Comp Eff Res 2014; 3: 271–281.
- 6. Campbell MJ. Randomisation in cluster trials. Scharrvids, May 2015. https://www.youtube.com/watch?v=PD4_DFiwg3E&index=3&list=PL1mJ7IZ3qFxiYlJ-jGZ1cf__ZVC08mymM (accessed Mar 2018).
- 7. Matthews JN, Altman DG, Campbell MJ, Royston P. Analysis of serial measurements in medical research. BMJ 1990; 300: 230–235.
- 8. Abramsky T, Devries K, Kiss L, et al. Findings from the SASA! study: a cluster randomized controlled trial to assess the impact of a community mobilization intervention to prevent violence against women and reduce HIV risk in Kampala, Uganda. BMC Med 2014; 12: 12.
- 9. Davies MJ, Heller S, Skinner TC, et al. Effectiveness of the diabetes education and self‐management for ongoing and newly diagnosed (DESMOND) programme for people with newly diagnosed type 2 diabetes: cluster randomized controlled trial. BMJ 2008; 336: 491–495.
- 10. REPOSE Study Group. Relative effectiveness of insulin pump treatment over multiple daily injections and structured education during flexible intensive insulin treatment for type 1 diabetes: cluster randomized trial (REPOSE). BMJ 2017; 30; 356: j1285.
Series Editors
John R Attia
Michael P Jones
No relevant disclosures.