Table 1 Demographic and developmental characteristics of the cohort. Statistic pertains to comparison of variable versus quantitative IQ (not ID group). We used Wilcoxon rank-sum test to examine IQ across sex; Spearman rank correlation to correlate IQ with age and VABS-II scores; and logistic regression model to compare ASD diagnosis with IQ.

Gender (% Female)

0.62

8

0.55

20

0.42

62

0.47

90

W = 1194

0.13

Age at evaluation (years)

7.48

1.32

8

11.69

5.03

20

8.15

4.58

62

8.88

4.72

90

r_s = -0.08

0.45

VABS-II Adaptive Behavior Composite Standard Score

74.12

7.94

8

60.5

10.06

20

44.56

9.43

62

50.73

13.59

90

r_s = 0.84

<0.0001

VABS-II Communication Standard Score

78

8.12

8

61.15

11.65

20

42.37

9

62

49.71

15.12

90

r_s = 0.84

<0.0001

VABS-II Socialization Standard Score

82.38

12.59

8

64.6

12.43

20

50.47

10.71

62

56.44

14.98

90

r_s = 0.76

<0.0001

VABS-II Daily Living Skills Standard Score

65.88

16.62

8

61.05

12.22

20

45.32

10.88

62

50.64

14.13

90

r_s = 0.75

<0.0001

VABS-II Motor Standard Score

71.29

10.03

7

69.15

10.54

13

53.1

7.9

50

57.9

11.45

70

r_s = 0.75

<0.0001

ASD (%)

0.14

7

0.35

20

0.73

59

0.59

86

IQ coefficient: estimate = -0.07, std error = 0.02

<0.0001