. Author manuscript; available in PMC: 2014 Feb 1.

Published in final edited form as: Child Dev. 2013 Apr 10;84(6):10.1111/cdev.12104. doi: 10.1111/cdev.12104

Table 4.

Estimates and Related Confidence Intervals (in Parentheses) of Genetic and Environmental Components of Covariance in the Latent Quadratic Growth Model Parameters

	Genetic		Shared env		Nonshared env
	Intercept	Linear slope	Intercept	Linear slope	Intercept	Linear slope
Word Identification
Slope	−0.01 (−0.14, 0.1)	—	−0.60 (−0.73, −0.46)^*	—	−0.004 (−0.03, 0.01)	—
Quadratic	−0.08 (−0.22, 0.06)	−0.17 (−0.36, −0.02)^*	0.50 (0.32, 0.65)^*	−0.81 (−0.93, −0.59)^*	−0.003 (−0.02, 0.02)	0.0004 (−0.02, 0.002)
Word Attack
Slope	−0.06 (−0.33, 0.16)	—	−0.43 (−0.65, −0.16)^*	—	0.02 (−0.03, 0.05)	—
Quadratic	0.02 (−0.26, 0.35)	−0.47 (−0.94, −0.11)^*	0.36 (0.03, 0.63)^*	−0.48 (−0.84, −0.02)^*	−0.04 (−0.08, 0.02)	−0.01 (−0.12, 0.003)
Reading Comprehension
Slope	−0.2 (0.46, 0.01)	—	−0.61 (−0.80, −0.36)^*	—	−0.06 (−0.03, −0.01)^*	—
Quadratic	0.21 (−0.05, 0.50)	−0.29 (−0.66, 0.07)	0.56 (0.28, 0.80)^*	−0.64 (−0.92, −0.29)^*	0.05 (0.01, 0.14)	−0.07 (−0.20, −0.01)^*
Rapid Naming
Slope	−0.44 (−0.71, −0.14)^*	—	−0.24 (−0.48, −0.01)^*	—	−0.24 (−0.36, −0.16)^*	—
Quadratic	0.40 (0.10, 0.67)^*	−0.40 (−0.72, −0.06)^*	0.25 (0.01, 0.48)^*	−0.34 (−0.61, −0.06)^*	0.24 (0.16, 0.36)^*	−0.25 (−0.39, −0.15)^*

Note. Quadratic = Quadriatic Slope; Word Identification = Woodcock Reading Mastery Test (WRMT) Word Identification; Word Attack = WRMT Word Attack; Reading Comprehension = WRMT Reading Comprehension; Rapid Naming = Comprehensive Test of Phonological Processing, Rapid Naming.

p < .05.