Table 4.

Phenotypically Standardized Genetic, Shared Environmental, and Nonshared Environmental Variance/Covariance Matrices: Phonological Awareness (PA), Rapid Automatized Naming (RAN), and Word Identification (Word ID)

	Months of school not includeda				Months of school includedb
Variable	PA	RAN	Word ID	Variable	PA	RAN	Word ID
Genetic				Genetic
PA	h2 = .61*			PA	h2 = .59*
RAN	.53*	h2 = .46*		RAN	.52*	h2 = .46*
Word ID	.24*	.21*	h2 = .59*	Word ID	.26*	.22*	h2 = .57*
Shared environment				Shared environment
PA	c2 = .27*			PA	c2 = .27*
RAN	.00	c2 = .24*		RAN	.00	c2 = .23*
Word ID	.27*	.04	c2 = .31*	Word ID	.22*	.04	c2 = .18*
Nonshared environment				Nonshared environment
PA	e2 = .12*			PA	e2 = .13*
RAN	.08	e2 = .30*		RAN	.08	e2 = .30*
Word ID	.02	.01	e2 = .10*	Word ID	.02	.01	e2 = .10*
Months of school				Months of school
PA	—			PA	sch2 = .01
RAN	—	—		RAN	.01	sch2 = .01
Word ID	—	—	—	Word ID	.04	.03	sch2 = .15*

Note. Asterisks indicate statistically significant values (using 95% confidence intervals in Mx). h² = heritability; c² = shared environment; e² = nonshared environment; sch = months of school.

^aSee Figure 1.

^bSee Figure 2.