Fig. 3: Path diagram of Nuclear Twin and Family Design (NTFD) structural equation model of educational attainment. | npj Science of Learning

Fig. 3: Path diagram of Nuclear Twin and Family Design (NTFD) structural equation model of educational attainment.

From: Conventional twin studies overestimate the environmental differences between families relevant to educational attainment

Fig. 3

The model for monozygotic (MZ) twins is displayed at the top and for dizygotic (DZ) twins at the bottom. Variances of latent factors are set to 1 unless otherwise specified (e.g., q = variance of A factor, x = variance of P factor). Path p was also set to 1 for model identification purposes. Social homogamy models set the genetic paths in red font to zero. A dominance model sets the non-additive genetic correlation between all siblings who are not MZ twins at 0.25 whereas an epistatic model sets that correlation at 0 (blue font).

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