Heritability is the proportion of variance caused by genetic factors of a specific trait in a population.[1] Falconer's formula is a mathematical formula that is used in twin studies to estimate the relative contribution of genetic vs. environmental factors to variation in a particular trait (that is, the heritability of the trait) based on the difference between twin correlations.[2] Statistical models for heritability commonly include an error that will absorb phenotypic variation that cannot be described by genetics when analyzed. These are unique subject-specific influences on a trait.[1] Falconer's formula was first proposed by the Scottish geneticist Douglas Falconer.[3]
The formula is