. Author manuscript; available in PMC: 2014 Oct 9.

Published in final edited form as: J Educ Psychol. 2013 Apr 29;105(3):633–648. doi: 10.1037/a0032581

Table 3.

Pre- and Posttest Means by Treatment Group and Effect Sizes

Measure	Time	Group				t/F^a	Effect size^b
		Tier 3		Typical school instruction
		M	SD	M	SD
WJ III Basic Reading	Pre	90.17	12.23	91.76	8.33	0.58
	Post	94.34	9.82	90.32	9.18	8.13^*	.56
WJ III Letter–Word Identification	Pre	87.62	12.62	90.04	9.49	0.84
	Post	91.96	9.63	89.68	9.48	7.90^*	.44
WJ III Word Attack	Pre	94.15	11.67	95.04	8.79	0.33
	Post	98.06	10.78	92.20	10.11	5.78^*	.65
TOWRE Word Reading Efficiency	Pre	80.47	10.17	81.80	9.62	0.54
	Post	88.91	12.44	85.60	9.62	4.35^*	.42
TOWRE Phonemic Decoding Efficiency	Pre	85.57	7.54	85.52	7.14	−0.03
	Post	91.36	9.38	88.00	7.14	2.25	.40
TOWRE Sight Word Efficiency	Pre	81.79	10.76	84.16	10.40	0.90
	Post	90.21	12.65	88.12	10.04	5.07^*	.39
DIBELS Oral Reading Fluency	Pre	18.15	10.23	17.08	12.50	−0.39
	Post	51.28	23.50	47.32	23.24	0.41	.12
WJ III Passage Comprehension	Pre	82.06	9.75	84.48	7.89	1.07
	Post	87.55	8.63	86.92	8.82	3.95^*	.34
Gates Passage Comprehension	Pre	12.87	15.21	11.36	9.79	−0.45
	Post	20.91	18.57	13.80	15.29	1.60	.35

Note. Typical school instruction (TSI) n = 25 for all measures; Tier 3 n = 47 for all measures except Gates and DIBELS posttest; for these measures, n = 46. WJ III = Woodcock–Johnson Tests of Achievement; TOWRE = Test of Word Reading Efficiency; DIBELS = Dynamic Indicators of Basic Early Literacy Skills; Gates = Gates–MacGinitie Reading Comprehension.

T tests were conducted to compare TSI and Tier 3 students at pretest. Repeated-measures analyses of variance were conducted to compare groups on pretest/posttest gains. The F value represents the Time*Treatment effect.

Effect sizes were calculated by dividing the difference in gain scores by the pooled standard deviation corrected for measurement error (the SD of the gain $scores / \sqrt{[2 * (1 - r)]}$ (McGaw & Glass, 1980).

p < .05.