Table 1.

ESS values computed for several sets of level 2 prior parameters ( ${\sigma }_{\alpha ,\phi }^2,{\sigma }_{\beta ,\phi }^2$, U_φ). The per-subgroup ESS values are based on assumed relative accrual rates .40, .30, .20, .10 for k = 1, 2, 3, 4.

${\sigma }_{\alpha ,\phi }^2={\sigma }_{\beta ,\phi }^2$	Uφ	ESS	Per-subgroup ESS
			1	2	3	4
100	5	6.6	2.6	2.0	1.3	0.7
25	5	7.1	2.8	2.1	1.4	0.7
4	5	9.1	3.6	2.7	1.8	0.9
25	2	25.8	10.3	7.7	5.2	2.6