. Author manuscript; available in PMC: 2011 Jan 12.

Published in final edited form as: Sci Stud Read. 2007 Feb 1;20(1-2):51–75. doi: 10.1007/s11145-006-9018-x

Table 6.

Genetic and environmental influences on grade 4 vocabulary and reading skills.

	A1	A2	A3	A4	a²
Vocabulary Latent Trait	.66^*				.44 (.30–.63)
Word Recognition Latent Trait	.62^*	.63^*			.77 (.57–.92)
Decoding Latent Trait	.47^*	.75^*	.00		.78 (.58–.90)
Comprehension Latent Trait	.90^*	.22^*	.00	.00	.86 (.63–.95)

	C1	C2	C3	C4	c²

Vocabulary Latent Trait	.74^*				.54 (.36–.68)
Word Recognition Latent Trait	.23^*	.29			.14 (.01–.34)
Decoding Latent Trait	.12	.27	.00		.09 (.00–.27)
Comprehension Latent Trait	.30^*	.08	.00	.00	.09 (.01–.31)

	E1	E2	E3	E4	e²

Vocabulary Latent Trait	.14^*				.02 (.003–.04)
Word Recognition Latent Trait	.28^*	.10			.09 (.06–.13)
Decoding Latent Trait	.34^*	.15	.00		.14 (.09–.19)
Comprehension Latent Trait	.21^*	.00	.00	.00	.04 (.01–.10)

Note. 95% confidence intervals in parentheses.

Significantly greater than zero. N (pairs) = 389.