Table 1.

Performance of the Samples on Key Language and Literacy Measures

	At-risk group			Control group
Time and measure	n	M	SD	n	M	SD	Reliability (α)	Cohen’s d
Time 1
Age in months	174	45.13	3.65	71	44.69	3.20	—	−0.12 [–0.40, 0.15]
Articulation (100)	172	73.60	20.43	71	89.48	7.58	—	0.90 [0.61, 1.18]
Word repetition (18)	161	13.51	3.96	68	16.74	1.93	.89	0.93 [0.63, 1.22]
Nonword repetition (18)	160	10.65	3.94	67	14.12	2.52	.89	0.97 [0.67, 1.27]
Basic concepts (18)	171	13.39	3.54	71	16.35	1.64	—	0.95 [0.66, 1.24]
Vocabulary (40)	169	15.00	7.06	71	20.69	5.24	.82	0.87 [0.58, 1.15]
Sentence structure (22)	170	11.21	4.16	71	14.39	3.27	.78	0.81 [0.52, 1.10]
Sentence repetition (16)	144	4.17	4.23	67	9.27	4.28	—	1.18 [0.87, 1.49]
Time 2
Letter-sound knowledge (32)	169	15.03	10.03	74	19.78	9.36	.95	0.48 [0.21, 0.76]
Writing letters (10)	169	3.30	3.03	74	4.65	3.05	.85	0.44 [0.17, 0.72]
Phoneme isolation: beginning of words (8)	126	4.59	2.95	70	5.76	2.54	.91	0.42 [0.12, 0.71]
Phoneme isolation: end of words (8)	121	2.06	2.87	68	3.44	3.32	.95	0.45 [0.15, 0.75]
RAN objects rate	150	.65	.19	71	.79	.17	—	0.78 [0.49, 1.07]
RAN colors rate	137	.56	.18	67	.69	.19	—	0.72 [0.42, 1.02]
Time 3
Early word reading (30)	167	13.89	8.70	74	20.15	8.04	.98	0.74 [0.45, 1.01]
Single-word reading (60)	165	7.88	9.30	74	15.52	13.53	—	0.71 [0.43, 0.99]
Spelling (5)	167	1.66	1.34	74	2.55	1.22	—	0.68 [0.40, 0.96]
Time 5
Reading comprehension (88)	155	54.66	9.35	72	60.58	8.71	.77	0.65 [0.36, 0.93]

Note: For most measures, the maximum possible score is given in parentheses. For rapid automatized naming (RAN), the rate was calculated as the number of correct responses (maximum of 40) divided by time (in seconds). Cohen’s ds for the mean difference between groups are adjusted for unequal sample size (Rosnow, Rosenthal, & Rubin, 2000); values in brackets are 95% confidence intervals.