Skip to main content

Table 1 Sample size estimates based on two-sided alpha = 0.05 for pairwise condition comparisons and 80 % power

From: See One, Do One, Order One: a study protocol for cluster randomized controlled trial testing three strategies for implementing motivational interviewing on medical inpatient units

Effect size Total sample size for an ordinary RCT (3 arms) ICC Number of providers Average number of patients per provider Total sample size for a cluster RCT unadjusted for estimated MI uptake Total sample size for a cluster RCT adjusted for estimated MI uptake
d = 0.4 300 0.07 31 31 930 1116
40 vs 18 % 195 0.1 30 17 510 765