. Author manuscript; available in PMC: 2016 Feb 2.

Published in final edited form as: Psychol Sci. 2013 Jun 19;24(8):1408–1419. doi: 10.1177/0956797612472204

Table 3.

Fixed Effects From the Within-Grade Hierarchical Linear Model for the Spring Letter-Word Identification Assessment (Reading Score)

Predictor	b	b SE	t	p
	First grade
Fitted mean reading, γ₀₀	460.025	1.220	t(26) = 376.976	<.001
Effect of ISI in Grade 1, γ₀₁	4.344	1.689	t(26) = 2.571	.016
Effect of fall reading, γ₁₀	0.601	0.023	t(444) = 25.192	<.001

	Second grade
Fitted mean reading, γ₀₀	479.401	2.441	t(46) = 196.390	<.001
Effect of ISI in Grade 2, γ₀₁	6.722	2.83	t(46) = 2.375	.022
Effect of fall reading, γ₁₀	0.671	0.022	t(885) = 29.873	<.001

	Third grade
Fitted mean reading, γ₀₀	502.134	0.711	t(37) = 706.189	<.001
Effect of ISI in Grade 3, γ₀₁	2.161	0.967	t(37) = 2.233	.032
Effect of fall reading, γ₁₀	0.826	0.026	t(38) = 31.769	<.001

Note: First-grade deviance = 3,690.28; second-grade deviance = 5,978.767976; third-grade deviance = 3,689.469255. The fitted mean spring reading score for the control group is represented by γ₀₀; the effect of the Individualizing Student Instruction (ISI) reading intervention in Grade 1 is represented by γ₀₁ (total fitted score = γ₀₀ + γ₀₁); and the effect of the fall reading W score is represented by γ₁₀.