Second, this type of analysis refers to the effective rather than objective stability of genetic and environmental effects (Turkheimer & Waldron, 2000). Objectively, one’s genotype (e.g., presence or absence of a specific polymorphism) or an environmental input (e.g., presence or absence of a spouse) may be the same at two time points, but the effective influence may be different. Effectively stable genes or environments are those that account for variance in the trait at both time points.
