MPIDR Working Paper
DF-analyses of heritability with double-entry twin data: asymptotic standard errors and efficient estimation
Kohler, H.-P., Rodgers, J. C.
MPIDR Working Paper WP-2000-005
Rostock, Max-Planck-Institut für demografische Forschung (Mai 2000)
This working paper has now been published. It is available at Behavior Genetics, 31(2) 179-191
In this paper we establish the asymptotic distribution of DeFries-Fulker (1985) regression estimates for heritability and shared environmental influences with double-entry twin data. A simple formula to estimate the covariance matrix of the coefficients in DF-regressions is provided, and applications to simulated data and Dabish twin data show that this method can substantially increase the statistical power of the analyses. We also provide an ´efficient DF-analysis´ that yields more precise estimates when additional covariates are included among the explanatory variables. (AUTHORS)