Goodness-of-Fit Tests for the Additive Risk Model with (p > 2)-Dimensional Time-Invariant Covariates

This paper presents methods for checking the goodness-of-fit of the additive risk model with p(> 2)-dimensional time-invariant covariates. The procedures are an extension of Kim and Lee (1996) who developed a test to assess the additive risk assumption for two-sample censored data. We apply the proposed tests to survival data from South Wales nikel refinery workers. Simulation studies are carried out to investigate the performance of the proposed tests for practical sample sizes.     

The Impact of Authority Relations and Feedback Delivery Method on Performance

ABSTRACT

The proliferation of technology has been changing feedback delivery methods in organizations. However, the effectiveness of feedback delivery methods can vary depending on social dynamics (e.g., authority relations) in the organization. The current study was designed to examine the impact of authority relations and feedback delivery methods on performance. A total of 120 participants were recruited to work on a simulated cell-phone assembly task and were exposed to one of the four feedback conditions: (a) authority figure with face-to-face feedback, (b) authority figure with e-mail feedback, (c) non-authority figure with face-to-face feedback, and (d) non-authority figure with e-mail feedback. Results showed that while both feedback delivery methods resulted in high performance with the presence of an authority figure, only face-to-face feedback resulted in high performance with a non-authority figure. Practical considerations for effective feedback delivery methods in relation to authority figures are also discussed.     

Powerful emotions: symbolic power and the (productive and punitive) force of collective feeling

This article argues that emotions can be a medium of social power. Using qualitative interview material from American Jews discussing anti-Semitism and its relationship to contemporary politics, it engages recent scholarship on emotions and political contention and shows how emotions make effective the various forms of symbolic exclusion by which group members exercise what Bourdieu calls symbolic power. It also explores the emotional connections to group membership by which some “excluded” members can engage in symbolic struggle over “the principles of vision and division” Bourdieu (Sociological Theory 7(1), 14–25, 1989) that define the group. Finally, it shows how emotions work to incite discipline in some group members, inspiring them to conform to dominant definitions of group membership so as to avoid both symbolic struggle and exclusion.     

The Clash between Social Policy and Traditional Values: Unmet Welfare Needs Sustained by the Culture of Familism in South Korea

Drawing from a wider study of the ideas of poverty and inequality in South Korea, this paper reports on the lived experiences of disadvantaged South Koreans and their relationship to the National Basic Livelihood Security System (NBLSS), a flagship social assistance program aimed at addressing poverty and inequality. Utilizing a cultural approach to understanding and analysing policy responses to poverty, the impact of familism in the application of the NBLSS safety net is examined. Research data is presented through the testimonies, obtained through qualitative research interviews, of disadvantaged research participants and those who work with them, as well as policy‐makers' perspectives, revealing key flaws in the current NBLSS policy objectives. It is clearly evident that, by clinging to outdated Confucian conceptualizations of familial piety as a justification for highly selectivist access to what is no more than a subsistence level of financial support for poor people, the proposition of a poverty safety net is compromised and is widely missing its aim of reducing poverty and inequality in contemporary South Korea.     

Self-Regulatory Driving Behaviors: Gender and Transportation Support Effects

This study examined the relationship between transportation support and self-regulatory driving behaviors of 566 community-dwelling older adults living in retirement communities, with a focus on gender differences. The results of logistic regression analysis showed that older women were more likely to avoid driving at night or on the highway than their male counterparts. Transportation support from peer friends was found to increase the likelihood of self-regulatory driving behaviors. The findings of this study imply that transportation policy and driving safety programs for older adults need to be developed, considering available transportation alternatives and gender differences in driving behaviors.     

A network ridesharing experiment with sequential choice of transportation mode

Within the last decade, there has been a dramatic bloom in ridesharing businesses along with the emergence of new enabling technologies. A central issue in ridesharing, which is also important in the general domain of cost-sharing in economics and computer science, is that the sharing of cost implies positive externalities and hence coordination problems for the network users. We investigate these problems experimentally in the present study. In particular, we focus on how sequential observability of transportation mode choices can be a powerful facilitator of coordination in ridesharing. Our study abstracts the essential issues of coordination in ridesharing into a directed network game with experimentally testable predictions. In line with the theoretical analysis, our experimental evidence shows that even a limited extent of sequential choice observability might lead to efficient coordination. However, convergence to efficiency is slower with more limited observability, resulting in a significant increase in travel cost.     

Nonstationary panel data analysis: an overview of some recent developments

This paper overviews some recent developments in panel data asymptotics, concentrating on the nonstationary panel case and gives a new result for models with individual effects. Underlying recent theory are asymptotics for multi-indexed processes in which both indexes may pass to infinity. We review some of the new limit theory that has been developed, show how it can be applied and give a new interpretation of individual effects in nonstationary panel data. Fundamental to the interpretation of much of the asymptotics is the concept of a panel regression coefficient which measures the long run average relation across a section of the panel. This concept is analogous to the statistical interpretation of the coefficient in a classical regression relation. A variety of nonstationary panel data models are discussed and the paper reviews the asymptotic properties of estimators in these various models. Some recent developments in panel unit root tests and stationary dynamic panel regression models are also reviewed.     

Attribution of tumour lethality and estimation of the time to onset of occult tumours in the absence of cause-of-death Information

A new statistical approach is developed for estimating the carcinogenic potential of drugs and other chemical substances used by humans. Improved statistical methods are developed for rodent tumorigenicity assays that have interval sacrifices but not cause-of-death data. For such experiments, this paper proposes a nonparametric maximum likelihood estimation method for estimating the distributions of the time to onset of and the time to death from the tumour. The log-likelihood function is optimized using a constrained direct search procedure. Using the maximum likelihood estimators, the number of fatal tumours in an experiment can be imputed. By applying the procedure proposed to a real data set, the effect of calorie restriction is investigated. In this study, we found that calorie restriction delays the tumour onset time significantly for pituitary tumours. The present method can result in substantial economic savings by relieving the need for a case-by-case assignment of the cause of death or context of observation by pathologists. The ultimate goal of the method proposed is to use the imputed number of fatal tumours to modify Peto's International Agency for Research on Cancer test for application to tumorigenicity assays that lack cause-of-death data.