cluster randomised trial
A type of clinical trial in which blocks of patients–as opposed to individual patients–are randomised.
Pros Ability to study interventions that can’t be directed to selected individuals; ability to control for contamination by others–e.g., one person’s changing behaviours may influence another person’s behaviour.
Cons Greater complexity in design and analysis; requires many more subjects to achieve the same statistical power as conventional trials.
Synonyms Cluster randomised controlled trial, group-randomised trial, place-randomised trial