This study investigates the impact of warfare on nuptial patterns, focusing on the trends and characteristics of age differences within marriage. Specifically, it explores the socio-demographic outcomes of the Imjin War (1592–1598) and post-war reconstruction in Korea, using the earliest extant Chosŏn household registers, compiled between 1606 and 1630. Individual-level microdata were derived involving 2,336 married couples based on 11,749 entries in these registers, covering four administrative districts located in the southeastern region of the Korean peninsula severely devastated by the war. Factors such as status, property, warfare, social practices, and legal regulations influenced spousal age differences. First, social rank and family wealth played pivotal roles, with age gaps widening as a husband's socio-economic status increased. Second, females born after 1580, whose first marriages were affected by the Imjin War and post-war circumstances, experienced an average marital age gap of about ten years. Third, this effect was further complicated by the imposition of socio-legal rules on remarriage; that is, the yangban entailed a pronounced age difference owing to the Neo-Confucian norm of chaste widowhood. This study enriches the understanding of historical marriage customs in Korea and offers insights for studies on age disparity in marriage.

This paper looks at the progress that the Mosaic database has enabled in the study of family structures in continental Europe in the past. Our main argument is that the combination of comprehensive archival research, digitization and computation, data mining, and open-access dissemination that is at the core of the Mosaic project is bringing about an important shift in the fundamental principles that have driven European family history research to date. These transformative features of Mosaic go beyond mere data infrastructural developments, as scaling up to much larger datasets leads to qualitative differences in measurements, methods, and questions. Integrating these perspectives can lead to an important incremental shift in both the scale and the scope of knowledge about historical European family systems.

This paper takes, as its starting point, Preston and Haines’ observation in Fatal Years that social class was the most important influence on infant and child mortality in England and Wales in the early twentieth century. A subsequent study suggested that this could in part be due to the spatial distribution of the different classes across different types of place, and that some of the mortality differences by social class might actually reflect the contextual effects of healthy and unhealthy places. Although this line of argument has received a considerable amount of attention in health geography literature, it has rarely been examined for a specific historic period, and then only within particular urban areas. In this paper, we apply multi-level models to a complete count individual-level dataset of the 1911 census of England and Wales, comparing influences on infant and child mortality at the level of the individual couple and for two spatial levels. We find that although most variation in infant and child mortality operates at the individual level, there is also important variation at the two spatial levels and part of the mortality differences between social classes is better explained by the areas in which people lived rather than by their social class. A consideration of independent variables at all three levels suggests that different spatial scales capture different sorts of influences on early age mortality.

Evolutionary demographers often invoke tradeoffs between reproduction and survival to explain reductions in fertility during demographic transitions. The evidence for such tradeoffs in humans has been mixed, partly because tradeoffs may be masked by individual differences in quality or access to resources. Unmasking tradeoffs despite such phenotypic correlations requires sophisticated statistical analyses that account for endogeneity among variables and individual differences in access to resources. Here we tested for costs of reproduction using N = 13,663 birth records from the maternity hospital in Basel, Switzerland, 1896–1939, a period characterised by rapid fertility declines. We predicted that higher parity is associated with worse maternal and offspring condition at the time of birth, adjusting for age and a variety of covariates. We used Bayesian multivariate, multilevel models to simultaneously analyse multiple related outcomes while accounting for endogeneity, appropriately modelling non-linear effects, dealing with hierarchical data structures, and effectively imputing missing data. Despite all these efforts, we found virtually no evidence for costs of reproduction. Instead, women with better access to resources had fewer children. Barring limitations of the data, these results are consistent with demographic transitions reflecting women's investment in their own embodied capital and/or the adoption of maladaptive low-fertility norms by elites.

Several studies assume that Calvinist Christianity severely undermined or even persecuted the practice of polyandry in the Sri Lankan areas under Dutch control. We analyze Dutch colonial policy and Church activities toward polyandry by combining ecclesiastical and legal sources. Moreover, we use the Dutch colonial administration of the Sinhalese population to estimate the prevalence of polyandry. We conclude that polyandry was far from extinct by the end of the Dutch period and we argue that the colonial government was simply not knowledgeable, interested and effective enough to persecute the practice in the rural areas under its control.

Theorems, proofs, laws and rules are commonly named according to the presumed investigator, but often earlier investigators have contributed substantially to the findings. One example of this is Hellin's law, which was named after Hellin, although he was not the first to discover it. In research on twinning and higher multiple maternities, the law has played a central role because it is approximately correct, despite showing discrepancies that are difficult to explain or eliminate. Several improvements to this law have been proposed. In this study, we re-examine some old papers to provide an overview of the scientists who have contributed to the genesis and the improvements of this law. In addition, we consider more recent contributions in which Hellin's law has been discussed and evaluated. It has been mathematically proven that Hellin's law does not hold as a general rule. However, most studies are based on empirical rates of multiple maternities, ignoring random errors. Such studies can never confirm the law, but only serve to identify errors too large to be characterized as random.

Assumptions about future mortality are more important than those for factors such as fertility, migration, disability trends or real interest rates for cost projections of the U.S. Old Age, Survivors, Disability and Health Insurance scheme. Recently, one factor has been assumed to be the key driver of future mortality in both official British population projections and actuarial ones: a ‘cohort effect’ associated with a group who were born in a period centred on the early 1930s who have been identified as having experienced particularly rapid improvements in mortality rates and are often referred to as the ‘golden generations’ or ‘golden cohorts’. The concept of ‘cohort effects’ is discussed; limitations of national-level cohort data considered; and methods for identifying such effects are reviewed. Particular attention is given to the analysis of populations which have been identified as having clear cut cohort effects; those of Britain and Sweden in the later part of the nineteenth century and early twentieth century, as well as the contemporary British population. The likely magnitude of such effects is discussed using a stylised model to assess the extent to which members of the ‘golden generations’ are especially privileged.

With reference to the concept of ‘the stages of life’ rather than ‘ages’, this paper examines the possibilities of estimating population figures for the First, Second and Third Ages in the United Kingdom, both for the present and at points in the past. The approach utilises the economic status of the citizenry – in particular, before, during and after paid work – rather than their ages or birth dates. The quantitative approximations are accompanied by a social commentary about the leverage of economic pressures, especially the calls or otherwise of employment, in effect, the Second Age, on the relative size of the First and Third Ages. It is concluded that much may be gained from ‘redrawing the composition of the population with social rather than demographic contours’.

A case-control study was conducted on the termination of menstrual life on mothers of twins. It involves a much larger data base and finer analyses, and makes use of the same methodology of a previous study. The time interval between the twin and the last confinement proved to be shorter in twin-bearing mothers than in a matched set of controls with singletons only after blocking of the effect of birth order, and despite the similarity of maternal age at delivery and confinements numbers. Mothers of like-sex twins only appeared to terminate reproductive life earlier than controls. The separate study of maternal age at twin confinement shows that the earlier the twin birth the shorter the menstrual life thereafter. Both like-sex twin births and early maternal age at delivery of a twin pair have the same shortening effect on subsequent menstrual life without clear evidence of additivity of effects as if both occurrences were alternatives with similar biological effects. Comparison of the results of the current study with those of our earlier analysis shows consistency on above results. However, the current study could not reproduce previous results on the role of unlike-sex twins or late maternal age at delivery on time to last confinement; yet, they cannot be discarded. It is suggested that increased power of interaction analyses and tighter matching of controls with respect to sex might improve the conclusions of subsequent studies.