Fig. 3.

A single cluster in the cluster randomised crossover (CRXO) design where (a) ρ > η, η > 0. b η → ρ. c η → 0. The green solid vertical lines indicate difference between true intensive care unit (ICU) mean length of stay (LOS) and true cluster-period mean LOS. The yellow (blue) curve indicates a normal distribution of patient LOS within each cluster or cluster-period where the patient or cluster was allocated to intervention S (T). The true difference between intervention S and T is zero. The total variance in LOS remains constant