cvcrand - Efficient Design and Analysis of Cluster Randomized Trials
Constrained randomization by Raab and Butcher (2001)
<doi:10.1002/1097-0258(20010215)20:3%3C351::AID-SIM797%3E3.0.CO;2-C>
is suitable for cluster randomized trials (CRTs) with a small
number of clusters (e.g., 20 or fewer). The procedure of
constrained randomization is based on the baseline values of
some cluster-level covariates specified. The intervention
effect on the individual outcome can then be analyzed through
clustered permutation test introduced by Gail, et al. (1996)
<doi:10.1002/(SICI)1097-0258(19960615)15:11%3C1069::AID-SIM220%3E3.0.CO;2-Q>.
Motivated from Li, et al. (2016) <doi:10.1002/sim.7410>, the
package performs constrained randomization on the baseline
values of cluster-level covariates and clustered permutation
test on the individual-level outcomes for cluster randomized
trials.