Table 2.

Summary of Developmental Characteristics on second and fourth year measures

	ASD (n=50)		DD (n=25)		TD (n=50)			Pairwise p-value
Characteristic	M	SD	M	SD	M	SD	F value	ASD-DD	ASD-TD
CSBS DP behavior sampled in the second year
Age in months	21.29a	1.92	20.64a	1.56	21.07a	1.75	1.23	.321	.911
Social composite	5.00a	2.36	7.92b	3.21	11.38c	2.57	82.77***	.001	.000
Speech composite	5.82a	2.62	7.16a	2.59	10.26b	2.43	39.86***	.116	.000
Symbolic composite	5.82a	3.07	6.52a	2.60	10.96b	2.56	48.77***	.661	.000
Total	73.88a	12.62	81.64b	11.86	102.54c	11.26	75.77***	.035	.000
Mullen scales of early learninge in the fourth year
Age in months	38.98a	9.83	35.85a	6.11	35.45a	5.42	1.23	.258	.085
Nonverbal DQ	76.00a	25.81	84.48a	20.12	114.08b	17.48	44.45***	.325	.000
Verbal DQ	68.00a	31.11	77.26a	21.04	108.93b	15.52	46.96***	.345	.000
Vineland adaptive behavior scalesf in the fourth year
Age in months	43.18a	14.48	47.04a	14.48			1.28	.284
Communication	75.88a	19.25	81.88b	16.99			4.49*	.015
Daily living	73.00a	12.86	83.08b	20.13			4.30*	.017
Social	74.79a	16.47	84.72b	17.12			3.77*	.028
Motor	78.96a	13.76	79.20a	26.28			0.27	.765
Adaptive Behavior	71.00a	14.02	79.08b	20.08			3.99*	.023

Note: Means in the same row with different subscripts differ significantly at p <.05 on the post-hoc Dunnet T3 comparison; F-values are Welch corrected when necessary for violation of homogeneity of variance as assessed by Levene’s test.

^dStandard Scores based on a M of 10 and SD of 3 for the Composite and M of 100 and SD of 15 for the Total.

^eDevelopmental Quotients (DQ) based on age equivalent divided by chronological age multiplied by 100

^fStandard Scores based on a M of 100 and SD of 15.

^*p <.05

^**p <.01

^***p <.001