Table 6.

Effect Size (Cohen’s d; Cohen, 1988) for ANOVA Contrast in Diagnostic Grouping of Early Gesture

		Pairwise Comparison for Diagnosis
Early Gestures	EMM	SE	p	Cohen’s d	Cohen’s d 95% CI	SE	df
12 Months
LL-Neg vs. HL-Neg	0.77	0.35	.073	0.27	[0.03, 0.51]	0.12	358
*** LL-Neg vs. HL-ASD	2.44	0.49	< .001	0.86	[0.52, 1.20]	0.17	358
*** HL-Neg vs. HL-ASD	1.67	0.44	< .001	0.59	[0.28, 0.90]	0.16	358
18 Months
LL-Neg vs. HL-Neg	0.92	0.50	.154	0.34	[0.02, 0.71]	0.19	144
*** LL-Neg vs. HL-ASD	2.98	0.71	< .001	1.11	[0.57, 1.65]	0.27	144
** HL-Neg vs. HL-ASD	2.05	0.66	.006	0.77	[0.27, 1.26]	0.25	144
24 Months
LL-Neg vs. HL-Neg	0.37	0.27	.350	0.18	[0.08, 0.43]	0.13	341
*** LL-Neg vs. HL-ASD	3.83	0.36	< .001	1.80	[1.44, 2.16]	0.18	341
*** HL-Neg vs. HL-ASD	3.46	0.33	< .001	1.63	[1.30, 1.96]	1.96	341

Notes. * p < .05, ** p < .01, ***p < .001. HL-ASD, high likelihood for autism infants who were diagnosed with ASD at 24 months of age; HL-Neg, high likelihood for autism infants who were not diagnosed with ASD at 24 months of age; LL-Neg, low likelihood for autism infants who were not diagnosed with ASD at 24 months of age. SD indicates standard deviation. Pairwise comparison indication is based on Tukey adjusted p-value of p <.05; EMS indicates estimated marginal means; SE indicates standard error; df indicates degrees of freedom; CI indicates confidence interval; Cohen’s d effect size index: 0.2 represents a small effect, 0.5 represents a medium effect, 0.8 represents a large effect