Table 3.

Number of individuals and number of clusters required for a cluster randomised crossover (CRXO), cluster randomised controlled trial (CRCT) and individually randomised controlled trial (IRCT) trial with ρ = 0.010 for each design and specified η for the CRXO design

	Number of required individuals	Number of required ICUs
CRXO
ρ = 0.010, η = 0.007 (equal cluster sizes)	51,581	22
ρ = 0.010, η = 0.006 (equal cluster sizes)	63,811	27
ρ = 0.010, η = 0.007 (unequal cluster sizes)	41,208	23
CRCT	13,4792	113
IRCT	10,090	9

ICU intensive care unit