Variability of Travel Time,Congestion, and the Cost of Travel

The variability of travel time modifies the rush hour traffic and the cost of commuting. The bottleneck model of road congestion with fixed peak-load demand is augmented of an additive random delay. When individuals have (α-β-γ) preferences, there exists a unique Nash equilibrium. The variability of travel time leads to departure rates that are spread more evenly over the rush hour than when travel times are deterministic. This equilibrium mechanism mitigates both congestion and the cost of unreliability. This implies that “single-traveler models,” which treat congestion as an exogenous phenomenon, overestimate the value of reliability for the rush hour. The application with the uniform or with the exponential distribution helps appraise the overestimation.     

Measuring Attitudes About Intimate Partner Violence Against Women: The ATT-IPV Scale

In lower-income settings, women more often than men justify intimate partner violence (IPV). Yet, the role of measurement invariance across gender is unstudied. We developed the ATT-IPV scale to measure attitudes about physical violence against wives in 1,055 married men and women ages 18–50 in My Hao district, Vietnam. Across 10 items about transgressions of the wife, women more often than men agreed that a man had good reason to hit his wife (3 % to 92 %; 0 % to 67 %). In random split-half samples, one-factor exploratory factor analysis (EFA) (N ₁ = 527) and confirmatory factor analysis (CFA) (N ₂ = 528) models for nine items with sufficient variability had significant loadings (0.575–0.883; 0.502–0.897) and good fit (RMSEA = 0.068, 0.048; CFI = 0.951, 0.978, TLI = 0.935, 0.970). Three items had significant uniform differential item functioning (DIF) by gender, and adjustment for DIF revealed that measurement noninvariance was partially masking men’s lower propensity than women to justify IPV. A CFA model for the six items without DIF had excellent fit (RMSEA = 0.019, CFI = 0.994, TLI = 0.991) and an attitudinal gender gap similar to the DIF-adjusted nine-item model, suggesting that the six-item scale reliably measures attitudes about IPV across gender. Researchers should validate the scale in urban Vietnam and elsewhere and decompose DIF-adjusted gender attitudinal gaps.     

Model-based Clustering of Sequential Data with an Application to Contraceptive Use Dynamics

ABSTRACT

Multi-state models describe the transitions people experience as life unfolds. The transition probabilities depend on sex, age, and attributes of the person and the context. Empirical evidence suggests that attributes that cannot be measured directly may at most be inferred from a long list of observable characteristics. A cluster-based, discrete-time multi-state model is presented, where transition probabilities are estimated simultaneously for several subpopulations of a heterogeneous population. The subpopulations are not defined a priori but are determined on the basis of similarities in behavior in order to determine which women exhibit similar characteristics with respect to method choice, method switch, discontinuation and subsequent resumption of contraceptive use. The data are from the life history calendar based on the Brazilian Demographic and Health Survey 1996. The parameters of the model are estimated using the EM algorithm. Seven subpopulations with heterogeneous transition probabilities are identified.     

Editorial

This paper uses the empirical characteristic function (ECF) procedure to estimate the parameters of mixtures of normal distributions. Since the characteristic function is uniformly bounded, the procedure gives estimates that are numerically stable. It is shown that, using Monte Carlo simulation, the finite sample properties of th ECF estimator are very good, even in the case where the popular maximum likelihood estimator fails to exist. An empirical application is illustrated using the monthl excess return of the Nyse value-weighted index.     

Bayesian adaptive lasso with variational Bayes for variable selection in high-dimensional generalized linear mixed models

This article describes a full Bayesian treatment for simultaneous fixed-effect selection and parameter estimation in high-dimensional generalized linear mixed models. The approach consists of using a Bayesian adaptive Lasso penalty for signal-level adaptive shrinkage and a fast Variational Bayes scheme for estimating the posterior mode of the coefficients. The proposed approach offers several advantages over the existing methods, for example, the adaptive shrinkage parameters are automatically incorporated, no Laplace approximation step is required to integrate out the random effects. The performance of our approach is illustrated on several simulated and real data examples. The algorithm is implemented in the R package glmmvb and is made available online.     

Growth,inequality and poverty in Vietnam: How did trade liberalisation help the poor, 2002–2008

Using the Vietnamese Living Standards Surveys for 2002, 2004, 2006 and 2008, we explore how provinces with differential access to trade liberalisation reforms differ in their pro-poor growth performance in Vietnam. Using both non-parametric and parametric estimation, we find strong, robust evidence of pro-poor growth in provinces with greater exposure to trade liberalisation. Using censored and uncensored regressions, the study also shows that increased wages play a critical role in this outcome. Our analysis enables identification of the core mechanisms through which the poor materialise their gains from trade-driven growth in a transition economy.     

The impact of remittances from Canada's seasonal workers programme on Mexican farms

Based on a survey of participants in Canada's Seasonal Agricultural Workers Program, the authors’ three‐stage least squares estimation of a simultaneous equation model finds that migrants’ remittances enhance on‐farm investments in Mexico, which, in turn, increase farm income. Remittances are also found to have a positive influence on non‐farm income in Mexico, by giving respondents the possibility of starting a new business and diversifying their investments. These results support the hypothesis underlying the “new economics of labour migration” that remittances contribute to economic development by relaxing the credit constraint on the investment function of family farms.     

The Value of Community Cohesion Among Vietnamese Students in Era of Urbanisation and Globalisation

The concept of community cohesion as applied in social research is about more than tackling social exclusion and also involves sustaining relationships of trust and neighbourly interaction. Community cohesion is a function of connections and relations maintained between individuals, groups and associations. It can be fostered through measures that build feelings of trust, safety and belonging between people and can form a basis for shared values and norms of behaviour. This concept originates from Emile Durkheim, who identified the interdependence between members of a social group who share solidarity, loyalties and responsibilities. In Vietnam, various idioms and proverbs about social solidarity and social cohesion express the significant role of community in the lives of individuals as well as an individual’s responsibilities towards the community. Recent public debates suggest that social cohesion is changing or fraying, especially among youth, owing to the social, economic and cultural impacts of globalisation and urbanisation. However, there is lack of research focusing on community cohesion among young people in general and students in particular in the Vietnamese context. This paper reports on a research project on student life conducted in twelve Hanoi universities, and with 484 research participants, utilizing surveys, interviews and focus groups. This paper aims to identify the current situation and trends in student values with regards to community, particularly their views on community participation, and their responsibilities to communities, friends and society in general. The findings suggest that in spite of significant changes associated with urban life and globalisation, students still positively value community cohesion and engage in practices that maintain solidarity, trust and interdependencies with a range of consociates.     

Use of senior centers as a moderator of stress related distress among Latino elders

Little is known about the moderating effects of community services on psychological distress among Latino elders. This study explores the use of senior centers as an intervention strategy to moderate the harmful impact of stress on psychological distress. The study was conducted using data from the 1988 National Survey of Hispanic Elderly People (N=2,299). To examine the direct and moderating effects of the use of senior centers on the relationship between stress and psychological distress we applied multiple regression analysis to an initial model, a direct effect model, and a moderating model. The results indicated that, under stressful life situations, respondents who used senior centers experienced lower levels of psychological distress than those who did not. Implications of the findings for senior centers and for further research are discussed.