Accounting for complex intracluster correlations in longitudinal cluster randomized trials: a case study in malaria vector control

Table 1 Visualization of five possible correlation structures for longitudinal cluster randomized trials

Correlation structure	Intracluster correlation matrices
Exchangeable
Nested Exchangeable
Exponential decay
Toeplitz
Unstructured

ρ_w/ρ_wi = within-period ICC, ρ_b/ρ_bi = between-period ICC, ρ_ij = the correlation between two within-cluster observations collected during the i-th and j-th period, r = cluster autocorrelation
Each correlation matrix shows a design with 3 periods and 2 cluster-period sizes. Across blocks, it shows the between period correlations between any individual from two periods. Within each block, correlations show the correlation between two individuals within the same period. ρ_ij is equal to ρ_ji

ISSN: 1471-2288