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...

In this paper we introduce a new set of period parity progression measures with continued fertility postponement in order to account for two distinct implications caused by delays in childbearing: tempo distortions imply an underestimation of quantum of fertility in observed period data, and the...

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...

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In this paper we apply tempo-adjusted period parity progression ratios (Kohler and Ortega 2001) to Sweden, the Netherlands and Spain. These countries represent three distinct demographic patterns in contemporary Europe and are of particular interest for demographers. The goal of our analyses is...

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...

This paper presents a toolkit for measuring and analysing inter-individual inequality in length of life by Gini coefficient. Gini coefficient is treated as an additional function of the life table. A new method for the estimation of Gini coefficient from life table data has been developed and...

We investigate the timing of fertility and marriage as it depends on educational attainment utilizing a birth-month experiment in Sweden that leads to exogenous variation in the age at completing schooling. Our analysis finds that the difference of 11 months in the age at school-leaving between...

In this paper, a multilevel approach is used to investigate whether and how regional social contexts influence first and second birth probabilities of women living in western Germany during the 1980s and 1990s. In the theoretical part it is argued that regional opportunity structures as well as...

In this paper we use new methods and data to reassess the relationship between the age at first birth and completed fertility. In particular we attempt to properly estimate the postponement effect, i.e., the reduction in fertility associated with a delay in childbearing, using a sample of Danish...