對Holzinger遺傳係數h2之評註

A Note on Holzinger's Heritability Coefficient h2

本文指出Holzinger（1973）所發展而廣為使用的遺傳係數h2並無確實理論根據，因其推演過程不嚴謹。Holzinger所用以推導h2的變異數成分模式和其認為h2估計遺傳變異數比值的說法隱含了一個違反事實的論點，即異卵雙生子無任何基因相同。而另一係數，Nichols的HR，雖由傳統的變異數成分模式推導所得，然其必要條件卻缺乏實徵上的表面效度。

It is shown that the still widely used heritability estimate h2 developed by Holzinger (1937) is not valid because Holzinger's derivation of it was unsound: The variance component mode l he used to derive h2, together with his claim that it estimates the genetic variance ratio, imply the counterfactual assertion that dizygotic twins share no genes. While a competing coefficient, Nichols' HR, does indeed follow from the conventional variance component model, the necessary conditions it rests on lack empirical face validity.