Table 3.

Random Coefficients Model Estimate for Letter-Word Identification W Score with Intercept at T₅

Effect	Estimate	Effect size	t or Z value*	p value
Fixed effects
Intercept	477.05		144.17	< .0001
Condition1	8.52	0.245	2.12	0.0346
Linear time	18.36	1.070	9.25	< .0001
Linear × condition	−1.52	0.069	−0.60	0.5461
Quadratic time	−1.77	0.500	−4.32	< .0001
Quadratic × condition	−1.12	0.223	−1.93	0.0545
Selection2	13.54	0.348	3.01	0.0029
Condition × selection	−4.45	0.083	−0.72	0.4699
Linear × selection	−0.64	0.059	−0.51	0.6128
Linear × condition × selection	−3.62	0.245	−2.12	0.0349
Ethnicity3	2.68	0.090	0.78	0.4342
Linear × ethnicity	4.06	0.494	4.27	< .0001
Grade level4	2.82	0.106	0.92	0.3561
Linear × grade level	−12.15	1.655	−14.31	< .0001
Random effects
Intercept	289.79		5.30	<.0001
Linear time	8.68		0.21	0.8299
Quadratic time	1.14		0.50	0.6187
Residual	254.67		14.60	<.0001
Covariance between intercept and time	−174.18		−5.50	<.0001
Covariance between intercept and quadratic	−46.61		−6.37	<.0001
Covariance between time and quadratic	1.39		0.15	0.8810

^*t value for fixed effects, Wald Z values for random effects

¹Condition coded 1 for intervention 0 for control

²Selection coded 1 for aggression 0 for reading

³Ethnicity coded 1 for Hispanic 0 for non-Hispanic

⁴Grade level coded 1 for 2^nd & 3^rd 0 for Kindergarten & 1^st