Table.

Participant demographics and motion measures at each matching stage.

A. Full Sample (FS set)					B. After Quality Check for Motion (QC set)				C. After Quantitative Motion Matching (QM set)
	ASD (n=57, 13 females) mean ± SD; [range]	TD (n=50, 12 females) mean ± SD; [range]	Percent Difference	p- value	ASD (n=36, 7 females) mean ± SD; [range]	TD (n=39, 10 females) mean ± SD; [range]	Percent Difference	p- value	ASD (n=30, 6 females) mean ± SD; [range]	TD (n=34, 9 females) mean ± SD; [range]	Percent Difference	p- value
Age (years)	13.28±2.92	12.75±2.78	4.02	0.35	13.65±2.88	12.78±2.63	6.6	0.17	13.86±3.01	13.08±2.68	5.82	0.28
	[7.64-17.98]	[8.01-17.98]			[8.68-17.80]	[8.02-17.59]			[8.68-17.80]	[8.02-17.59]
Non-verbal IQ	103.18±18.62	107.40±13.53	4.01	0.19	104.82±19.34	107.28±12.89	2.32	0.52	105.61±17.43	107.76±12.38	2.02	0.57
	[53-140]	[77-137]			[53-140]	[83-137]			[53-140]	[86-137]
Verbal IQ	100.41±19.24	107.50±12.60	6.82	0.03	100.12±21.90	106.00±10.97	5.71	0.14	100.68±21.94	107.26±9.89	6.33	0.12
	[56-147]	[73-134]			[56-147]	[73-127]			[56-147]	[87-127]
SRS Total	81.00±10.13	42.20±5.46	62.98	<0.001	82.74±9.76	41.97±5.14	65.38	<0.001	82.90±8.81	41.90±5.03	65.7	<0.001
	[57-100]	[35-58]			[62-100]	[35-52]			[62-100]	[35-52]
ADOS S+C	12.83±4.15				13.21±4.28				13.74±4.36
	[7-22]				[7-22]				[7-22]
ADOS SBRI	2.30±1.55				2.12±1.43				2.22±1.42
	[0-6]				[0-5]				[0-5]
Average Translation (mm)	1.03±0.49	0.92±0.34	11.01	0.46	0.87±0.24	0.88±0.25	1.31	0.72	0.84±0.19	0.89±0.20	4.93	0.35
	[0.49-3.03]	[0.46-2.38]			[0.49-1.82]	[0.49-1.71]			[0.49-1.19]	[0.49-1.35]
Average Rotation (rad; X10-3)	6.48±4.23	5.68±3.51	13.1	0.20	4.86±1.96	4.64±1.95	4.73	0.56	4.57±1.55	4.49±1.59	1.92	0.78
	[1.54-21.63]	[2.39-20.71]			[2.31-11.70]	[2.39-12.25]			[2.31-8.56]	[2.39-8.63]
% Bad Slices	0.13±0.27	0.09±0.31	39.31	0.03	0.03±0.05	0.02±0.08	38.49	0.03	0.02±0.05	0.02±0.09	2.14	0.39
	[0-1.22]	[0-1.99]			[0.00-0.19]	[0.00-0.52]			[0.00-0.19]	[0.00-0.52]
Average Dropout Score	1.15±0.19	1.07±0.14	7.43	0.02	1.15±0.21	1.03±0.09	10.47	0.01	1.07±0.13	1.04±0.10	3.24	0.34
	[1-1.66]	[1-1.55]			[1.00-1.66]	[1.00-1.41]			[1.00-1.38]	[1.00-1.41]

Group differences in participant demographics and quantitative motion measures at each stage of matching. Age and behavioral measures tested with t-tests, motion measures tested with Mann-Whitney U Test due to non-normal distributions. FS = Full Set. QC = Quality-Checked subsample. QM = Quantitatively Matched subset. SRS = Social Responsiveness Scale. ADOS = Autism Diagnostic Observation Schedule. SBRI = Stereotyped Behaviors and Restricted Interests. S+C = Social and Communication subscores. rad = radians.