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...

Demographers have increasingly argued that social interaction is an important mechanism for understanding fertility behavior. Yet, substantial uncertainty exists whether ´social learning´ or ´social influence´ constitutes the dominant mechanism through which social networks affect...

Bongaarts and Feeney (1998) have recently proposed an adjusted total fertility rate to disentangle tempo effects from changes in the quantum of fertility. We propose an extension to the Bongaarts and Feeney formula that includes variance effects, i.e., changes in the variance of the fertility...

As the heterogeneity in life expectancy by socioeconomic status increases, pension systemsbecome more regressive implying wealth transfers from short to long lived individuals. Variouspension reforms aim to reduce these inequalities that are caused by ex-ante differences in lifeexpectancy....