TABLE 1.

Performance indices of the RF models on the test set (=test) and the previously unseen validation data set (=val) for nonverbal children and minimally verbal children

Number of features	AUC test	ACC test	Sens. test	Spec. test	Youden's J	McN	AUC val	ACC val	Sens. val	Spec. val
Nonverbal children
ADOS + ADI combination (N = 198)
All 66 features	0.86	0.88	0.79	0.94	0.69	1	0.86	0.81	0.83	0.80
Eighteen features (optimal model) (13 ADOS, 5 ADI‐R)	0.88	0.91	0.83	0.97	0.69	0.92	0.86	0.77	0.74	0.80
Three features (minimal model) (3 ADOS, 0 ADI)	0.79	0.83	0.78	0.81	0.66	0.09	0.76	0.78	0.83	0.73
ADOS alone (N = 466)
All 29 features	0.93	0.92	0.93	0.89	0.54	1	0.88	0.82	0.91	0.72
ADOS six features (optimal model)	0.89	0.90	0.95	0.84	0.50	0.20	0.84	0.78	0.89	0.67
ADOS four features (minimal model)	0.89	0.89	0.93	0.86	0.56	0.09	0.81	0.78	0.93	0.64
Minimally verbal children
ADOS + ADI combination (N = 304)
All 65 features	0.88	0.89	0.92	0.84	0.51	1	0.90	0.78	0.96	0.62
Sixteen features (optimal model) (11 ADOS, 5 ADI‐R)	0.87	0.89	0.90	0.85	0.52	0.94	0.90	0.80	0.93	0.67
Seven features (minimal model) (5 ADOS, 2 ADI)	0.83	0.85	0.89	0.82	0.51	0.21	0.87	0.74	0.89	0.59
ADOS alone (N = 566)
All 28 features	0.92	0.91	0.96	0.88	0.43	1	0.92	0.85	0.84	0.87
Seven ADOS features (optimal model)	0.91	0.91	0.93	0.89	0.45	0.21	0.89	0.83	0.82	0.84
Six ADOS features (minimal model)	0.91	0.91	0.96	0.86	0.41	0.14	0.90	0.84	0.85	0.82

Abbreviations: ACC, accuracy; ADI‐R, Autism Diagnostic Interview‐Revised; ADOS, Autism Diagnostic Observation Schedule; AUC, area under the curve; J, Youden's Index; McN, McNemar level of significance—each model tested against the full‐feature sets of available features; Sens, sensitivity; Spec, specificity.