Life‐Course Transitions and the Age Profile of Internal Migration

Despite underlying regularities in the age profile of migration, there is mounting evidence of cross‐national variations in the ages at which migration occurs. Explanations for these differences have variously been sought by reference to cultural, social, and economic factors, and through analysis of reasons for moving. There is also a growing body of work linking migration events to particular transitions in the life course. We set out a conceptual framework that links contextual factors to the age structure of migration through life‐course transitions that act as proximate determinants of the age at migration. We propose metrics to capture the prevalence, timing, and spread of four key life‐course transitions: education completion, labor force entry, union formation, and first childbearing. We then seek to quantitatively establish the link between these indicators and the age and intensity of internal migration at its peak for a global sample of 27 countries. Correlation and factor analysis reveal substantial diversity in the timing and spread of transitions to adult roles, and show that cross‐national differences in the age profile of migration closely parallel variations in the age structure of the life course for over two‐thirds of countries. Migration age profiles are aligned with transitions to adulthood for both sexes but most strongly among women.     

A Note on standardized rates

The authors of this note demonstrate that it is not necessarily true that the standardized death-rate of a combined population will lie between the standardized death-rates of its two components.     

The consequences of early marriage on marital dissolution

Research has been consistent in documenting the direct negative effect of early marriage on marital stability, while disagreeing over the level of influence of status attainment measures on divorce. However, the discipline has failed to come to consensus on the complexity of these relationships: that early marriage may operate indirectly through mediating variables to increase the likelihood of divorce. The focus of this paper is an analysis of a path model which includes the estimated effects of antecedents of early marriage, early marriage and education on the probability of divorce. Findings using the General Social Surveys support research that suggests that early marriage is the most important variable influencing divorce. Further, little influence of the early marriage measure through education was found.     

Block diagrams and splitting criteria for classification trees

Various aspects of the classification tree methodology of Breiman et al., (1984) are discussed. A method of displaying classification trees, called block diagrams, is developed. Block diagrams give a clear presentation of the classification, and are useful both to point out features of the particular data set under consideration and also to highlight deficiencies in the classification method being used. Various splitting criteria are discussed; the usual Gini-Simpson criterion presents difficulties when there is a relatively large number of classes and improved splitting criteria are obtained. One particular improvement is the introduction of adaptive anti-end-cut factors that take advantage of highly asymmetrical splits where appropriate. They use the number and mix of classes in the current node of the tree to identify whether or not it is likely to be advantageous to create a very small offspring node. A number of data sets are used as examples.