Table 2a.

AIMS observed means (variances) and unconditional growth model by assessment condition and intervention group

Measure/Parameter	Familiar			Novel
	Typical	Struggling-NI	Struggling-I	Typical	Struggling-NI	Struggling-I
	Observed M (VAR)
AIMS time 1	23.2 (67.4)	12.7 (72)	13.9 (67.3)	23.8 (71.6)	14.5 (67)	14.6 (70.3)
AIMS time 2	27.1 (79.9)	15.3 (107.8)	15.9 (66.1)	24.8 (76.5)	15.2 (86.3)	15.4 (73.9)
AIMS time 3	31.0 (113.4)	16.5 (142.3)	18.0 (106.8)	26.9 (89.6)	16.9 (75.7)	15.6 (76)
AIMS time 4	35.1 (119.3)	19.2 (139.9)	21.2 (118.6)	29.1 (98.4)	17.1 (104.2)	17.5 (95)
AIMS time 5	37.2 (121.9)	21.0 (199.9)	24.6 (130.9)	29.8 (106.1)	19.3 (106.3)	18.1 (109.5)
	Unconditional Growth Model Estimates
Means
I	23.4	12.8	13.4	23.5	14.3	14.4
S	1.82	1.04	1.32	0.83	0.58	0.46
Variances/Covariances
I	55.7	65.7	45.3	51.5	49.8	39.2
S	0.25	0.59	0.37	0.17	0 Fixed	0.25
I with S	2.46	3.46	2.08	1.42	0 Fixed	1.51
Residual
AIMS time 1	15.8	9.4	20.7	23.5	25.9	29.7
AIMS time 2	14.1	18.2	14.6	18.2	30.2	27.1
AIMS time 3	20.9	28.5	33.5	20.3	32.2	26.8
AIMS time 4	21.6	32.5	31.3	20.6	56.3	25.7
AIMS time 5	23.6	35.7	33.7	28.7	42.1	29.3
	Slope Properties
Reliability a	.33	.46	.35	.32		.30
Variance Extracted b
Time 1 Intercept	.27	.38	.28	.19	NA	.22
Time 5 Intercept	.29	.44	.30	.20	NA	.21

Note. CFI = .99, RMSEA = .07, SRMR = .05. All effects are unstandardized. 0 Fixed means variance/covariance was fixed to 0 in order to obtain proper estimates.

^aThe ratio between model estimated true slope variance and observed variance in OLS estimated individual slopes (National Center on Response to Intervention, 2011).

^bThe average variance extracted by slope, ρ_ve (η_s) (Fornell & Larcker, 1981).