Table 1. Autism Diagnostic Observation Schedule means (standard deviations in parentheses) for High-risk Autism group with and without a later Autism Spectrum Disorder diagnosis.

	High-risk Autism (No diagnosis)	High-risk Autism (With diagnosis)	Significance and Effect Size
Autism Diagnostic Observation Schedule - Module 1	n = 11	n = 3
Social Total	2.64 (1.75)	5.00 (3.00)	p = .096, d = 1.27
Range	0-6	2-8
Communication Total	1.45 (1.13)	1.67 (1.15)	p = .78, d = .21
Range	0-4	1-3
Social+Communication Total	4.09 (2.30)	6.67 (4.04)	p = .16, d = 1.04
Range	1-8	3-11
Autism Diagnostic Observation Schedule - Module 2	n = 18	n = 5
Social Total	1.56 (1.46)	5.80 (1.79)	p < .001, d = 2.9
Range	0-4	3-7
Communication Total	1.89 (1.41)	3.60 (2.07)	p = .041, d = 1.15
Range	0-4	1-6
Social+Communication Total	3.44 (2.15)	9.40 (3.78)	p < .001, d = 2.45
Range	0-7	4-13

Note. Autism Diagnostic Observation Schedule (ADOS) data are from the most recent ADOS administration (either 24 or 36 months). Final sample included n=29 for High-risk Autism with no clinical diagnosis and n=8 for High-risk Autism with an Autism Spectrum Disorder diagnosis at the most recent lab visit.