Figure 3.

Three examples of within-cluster correlation patterns implied by the random coefficient model. A trial with J = 5 is assumed throughout; the diagonal cells present the within-period ICC values, while the off-diagonal cells present the between-period ICC values. White color indicates a smaller ICC value while red color indicates a larger ICC value. The variance components parameters are assumed as ${\sigma }_{\text{ϵ}}=6,{\tau }_{\alpha }=1,{\tau }_{\xi }=0.5$ and the covariance parameter (a) ${\sigma }_{\alpha \xi }=-0.5$, (b) ${\sigma }_{\alpha \xi }=0$, (c) ${\sigma }_{\alpha \xi }=0.5$. (a) Negative covariance σ_αξ = − 0.5; (b) Zero covariance σ_αξ = 0; (c) Positive covariance σ_αξ = 0.5.