Table 1. Fit indices of cluster solutions identified through k-means cluster analysis at each wave.

	T0		T1			T2
	#5	#6	#4	#5	#6	#5	#6	#7
C-index	.15	.18	.11	.08	.06	.05	.10	.11
G(+) index	.04	.03	.05	.03	.02	.03	.03	.02
Gamma index	.75	.80	.76	.81	.86	.83	.85	.87
Point biserial correlation	.43	.41	.47	.41	.40	.42	.43	.41
ESS	64.52	70.92	61.23	7.12	75.66	71.49	76.53	79.62

Note. ESS = explained error sum of squares of the given classification.