Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

This study explores how researchers' analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers' expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team's workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers' results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.

Wealth in Couples: Introduction to the Special Issue

The assumption that economic resources are equally shared within households has been found to be untenable for income but is still often upheld for wealth. In this introduction to the special issue “Wealth in Couples”, we argue that within-household inequality in wealth is a pertinent and under-researched area that is ripe for development. To this end, we outline the relevance of wealth for demographic research, making the distinction between individual and household wealth. Drawing on a life-course perspective, we discuss individual wealth accumulation within couples and its links to family-demographic processes, the institutional context, and norms on pooling and sharing. We conclude with a brief summary of the main findings from the special issue and highlight implications for demographic research and for future research in this field.

Who Opts Out? The Customisation of Marriage in the German Matrimonial Property Regime

This study examines the prevalence of marital contracts across marriage cohorts (1990–2019) in Germany. We further investigate the characteristics of spouses who signed a marital contract. Using cross-sectional data from the German Family Panel (pairfam, 2018/19), we employ complementary log–log and multinomial logistic regression models to predict the prevalence and the type of marital contracts. The results show that 5% of all married couples opt out of the default matrimonial property regime by signing a contract in Germany. Differentiating between contract types, most couples either specify a separation of property (40%) or modify the default community of accrued gains (31%). We find an increase in the prevalence of marital contracts across marriage cohorts. The decision to opt out of the default is strongly positively associated with self-employment that often requires the customisation of asset ownership structures within marriage. Married individuals with prior divorce experiences are more likely to opt for the separation of property, indicating that the awareness of the economic consequences of divorce promotes the individualisation of marriage. Our results are in line with the cross-national trend towards customised marriages, although the trend in Germany is less pronounced than in other countries.

Gendered employment trajectories and individual wealth at older ages in Eastern and Western Germany

This study examines the association between employment trajectories and retired men's and women's individual wealth at older ages in the two distinct welfare state contexts of Eastern and Western Germany. Because of the increasing re-marketization of retirement provisions, wealth is becoming increasingly important for retirees' economic well-being. Using data from the German Socio-Economic Panel Study (2002, 2007, 2012 and 2017), we conduct sequence and cluster analyses to identify groups of typical employment trajectories of men and women in Eastern and Western Germany. For men, we find that continuous full-time employment is positively associated with net wealth at older ages, whereas early retirement and long-term unemployment are negatively associated with wealth. These associations are similar for housing and non-housing wealth in both contexts. For women in Western Germany, a low labour market participation is associated with higher levels of housing wealth and lower levels of non-housing wealth compared with female full-time employees. The results point to gendered wealth accumulation due to differences in men's and women's labour market participation in gender-unequal welfare state contexts. The associations between employment and wealth are slightly weaker in Eastern Germany, indicating that the socialist regime of the GDR restricted the ability to accumulate wealth.

Birth cohort, ageing and gender ideology: Lessons from British panel data

Individuals' gender attitudes influence their behaviors, and adherence to traditional gender ideology is an important mechanism contributing to the (re)production of gender inequalities. In developed nations, the 'gender revolution' was accompanied by marked societal shifts towards gender-egalitarian attitudes, but these trends have recently stalled. In this paper, we re-examine the role of birth cohort and ageing in influencing gender ideology through the lens of life-course theory and leveraging British panel data. We contribute to the field by considering cohort-differences in ageing effects on gender ideology and documenting within-cohort variability in such effects. We find that (i) people from older cohorts hold comparatively more traditional gender attitudes, (ii) the effect of ageing on gender ideology is positive, (iii) there are cohort-differences in these ageing effects, (iv) gender-attitude trajectories are less predictable in younger than older cohorts, and (v) factors capturing life-course experience explain little of the cohort differences. Our findings highlight important avenues for future research on gender ideology change, and offer insights into the likely pace and direction of social movements towards gender egalitarianism.

Long-term Health Consequences of Adverse Labor Market Conditions at Time of Leaving Education: Evidence from West German Panel Data

Using longitudinal survey data from the Socio-Economic Panel Study ( N = 3,003 respondents with 22,165 individual-year observations) and exploiting temporal and regional variation in state-level unemployment rates in West Germany, we explore differences in trajectories of individuals' self-rated health over a period of up to 23 years after leaving education under different regional labor market conditions. We find evidence for immediate positive effects of contextual unemployment when leaving education on individuals' health. We find no evidence for generally accelerated or decelerated health deterioration when leaving education in high-unemployment contexts. We find, however, that individual unemployment experience when leaving education is associated with worse health and with more accelerated health deterioration in high-unemployment contexts. The cumulative experience of unemployment after leaving education does not mediate the influence of early labor market experiences for long-term health outcomes. In addition, our analyses indicate no gender differences in these results.

Intergenerational transmission of homeownership in Europe: revisiting the socialisation hypothesis

Socialisation towards homeownership during childhood has been proposed as one transmission channel of homeownership across generations in previous literature, but tests of this socialisation hypothesis are scarce. This study presents the yet most rigorous test of the socialisation hypothesis using retrospective life-history data (SHARELIFE, N=19,567 individuals) from 13 European countries. Event history and panel regression models are applied. Results show that socialisation in homeownership positively affects the hazard rates of entering homeownership for the first time and the probability to be a homeowner throughout individuals' lives net of other parental background variables and material transfers. We find a socialisation effect across divergent (but not all) examined countries. Further sensitivity analyses using a placebo test and a hypothetical confounder support the conclusion that being socialised in homeownership during childhood increases the chances of becoming and being a homeowner in later life.