Regression Analysis of Restricted Mean Survival Time Based on Pseudo-Observations

Regression models for survival data are often specified from the hazard function while classical regression analysis of quantitative outcomes focuses on the mean value (possibly after suitable transformations). Methods for regression analysis of mean survival time and the related quantity, the restricted mean survival time, are reviewed and compared to a method based on pseudo-observations. Both Monte Carlo simulations and two real data sets are studied. It is concluded that while existing methods may be superior for analysis of the mean, pseudo-observations seem well suited when the restricted mean is studied.     

Relational and Overt Aggression in Childhood and Adolescence: Clarifying Mean‐level Gender Differences and Associations with Peer Acceptance

Research on relational aggression has drawn attention to how girls may be likely to aggress, but the role of gender is not fully understood. There are opposing views regarding whether relational aggression is most common among girls. Current findings demonstrate that when gender differences in relational aggression are assessed with peer nominations, gender differences favoring girls are more likely: (1) in adolescence than childhood; and (2) when statistical overlap with overt aggression is controlled. Results also indicated that associations of relational aggression with peer acceptance depend on the aggressor's gender, the peer rater's gender, and whether overlap with overt aggression is controlled. Associations of relational aggression with lower acceptance became non‐significant when overt aggression was controlled, suggesting that relational aggression displayed in isolation may not damage acceptance. In fact, in mid‐adolescence, girls’ relational aggression predicted greater liking by boys. Reducing relational aggression among adolescent girls may be especially challenging if the behavior is linked with acceptance by boys.     

Intra‐Household Specialization in Housework in the United States and Denmark*

Objective. Focusing on housework activities, we hypothesize that the degree of specialization is influenced by economic notions of efficiency, as well as by time constraints and egalitarian values. Methods. Employing time‐use data on U.S. and Danish couples, we construct a composite index measure of intra‐household specialization. We analyze the comparability of reported time use and our specialization index using different types of data, and then model specialization using a multivariate two‐limit Tobit. Results. We find evidence that Danish households specialize less than U.S. households and that children, particularly preschool‐aged children, are associated with significantly increased specialization in the United States but not in Denmark. Conclusions. We postulate that the more egalitarian social structure in Scandinavia is a driving force behind the lower rate of specialization observed in Denmark. Further, we believe the subsidized child‐care services provided by the Danish welfare system reduce the impact children have on specialization in ordinary housework tasks.     

Infants of Depressed Mothers Show Reduced Gaze Activity During Mother–Infant Interaction at 4 Months

Gaze is one of the main means of communication in young infants, and it has been shown to be important for subsequent socio‐emotional and cognitive development. Maternal depression is a well‐known risk factor for disrupting mother–infant interactions, but findings regarding gaze behavior in infants of depressed versus nondepressed mothers have been ambiguous. In this study, we examined gaze duration and activity in a sample of 27 infants of mothers with postpartum depression (PPD) and 49 infants of nondepressed mothers. Maternal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale, and diagnoses were confirmed in clinical interview. Infant gaze was assessed during 4‐month face‐to‐face interactions using continuous timed‐event coding with high temporal resolution. Although we found no differences in gaze duration, infants of PPD mothers had both significantly less Gaze On and also less Gaze Off events. Findings suggest that PPD is related to reduced gaze activity during mother–infant interaction in 4‐month‐olds. This reduced activity may have long‐term negative consequences for child development.     

‘La Lenin is my passport’: schooling,mobility and belonging in socialist Cuba and its diaspora

Based on an ethnographic study of transnational networks of alumni of an academically selective boarding school in Havana, this article explores the nexus between mobility, schooling and belonging in the context of socialist Cuba and its diaspora. Drawing on Goffman’s work, I argue that the boarding school experience was transformative; it facilitated or consolidated social mobility for its pupils, which later, for many, led to geographic mobility in the form of study and work outside Cuba. After graduating, alumni continue to identify with the school and to reproduce their alumni identities. The affective webs of belonging forged through family links and friendships fostered at the school constitute emotionally sustaining networks that also provide material support after migrating. I propose that the school represents a site of identification for a globally dispersed non-national diaspora and argue that migration scholars need to embed international migration within people’s lives more broadly.     

Marriage migration: just another case of positive assortative matching?

It is a stylized fact that marriage formation involves positive assortative matching on education. We also find this in the case of immigrants, even when they tend to “import” their spouses and potentially trade off education for other favorable characteristics. For Pakistanis, we find positive compensating differentials in terms of high education to youth having adopted host country norms, when marrying a marriage migrant. This indicates that Pakistani marriage migrants pay a premium to be able to marry and live in Denmark. For Turks, individuals having source country norms pay a premium in order to import a partner, indicating that unspoiled traditional norms are traded off for education.

Slack free MEA and RDM with comprehensive efficiency measures

This paper extends two directional distance function models, the Multi-directional Efficiency Analysis (MEA) Model and the Range Directional Model (RDM), in order to account for any type of technical inefficiency, i.e. both directional and non-directional inefficiencies. We first focus on the variable returns to scale (VRS) case, because both VRS-MEA and RDM are translation invariant models, which mean that both models are able to deal with negative data. Our main result is the definition of a new comprehensive efficiency measure which is units invariant and translation invariant and covers both models. Secondly, we introduce the RDM model under constant returns to scale (CRS) together with a new comprehensive efficiency measure.     

Matched survival data in a co-twin control design

When using the co-twin control design for analysis of event times, one needs a model to address the possible within-pair association. One such model is the shared frailty model in which the random frailty variable creates the desired within-pair association. Standard inference for this model requires independence between the random effect and the covariates. We study how violations of this assumption affect inference for the regression coefficients and conclude that substantial bias may occur. We propose an alternative way of making inference for the regression parameters by using a fixed-effects models for survival in matched pairs. Fitting this model to data generated from the frailty model provides consistent and asymptotically normal estimates of regression coefficients, no matter whether the independence assumption is met.