Table 3.

Hierarchical linear regression analyses predicting child communication variables from treatment status and Time 1 object interest

	Dependent variables
	Residualized gain scores of initiating joint attention			Residualized gain scores of initiating behavioral requests			Residualized gain scores of PIA-CV nonverbal communication			Residualized gain scores of weighted frequency of intentional communication
Predictors	ΔR2 a	B	95% CI	ΔR2 a	B	95% CI	ΔR2 a	B	95% CI	ΔR2 a	B	95% CI
Intercept		.039	[−.39, .47]		.017	[−.12, .15]		.079	[−.19, .35]		.834	[−.27, 1.94]
Treatment Status	.01	.163	[−.45, .77]	.00	.004	[−.19, .20]	.01	−.086	[−.46, .28]	.01	−.499	[−1.99, .99]
DPA # Toys at T1	.03	.191	[−.11, .49]	.24***	.172	[.08, .27]	.05	.134	[−.06, .32]	.33**	1.514	[.65, 2.38]
Treatment Status × DPA # Toys at T1	.20**	−.664	[−1.06, −.27]	.21**	−.213	[−.34, −.09]	.13*	−.288	[−.53, −.04]	.29**	−1.718	[−2.76, −.67]
N	45			45			42			29

Note: The n’s displayed are smaller than those presented in Figure 1 and Table 2 when children were missing a specific outcome measure or the Time 1 measure to required to compute the residualized gain score; CI = confidence interval; PIA-CV = Parent Interview for Autism – Clinical Version; PCFP = Parent–Child Free Play; DPA = Developmental Play Assessment; T1 = 1st time point.

^aR squared change was calculated as the square of the part correlation coefficient.

^*p < .05.

^**p < .01.

^***p < .001.