Joint coverage probability in a simulation study on continuous-time Markov chain parameter estimation

Parameter dependency within data sets in simulation studies is common, especially in models such as continuous-time Markov chains (CTMCs). Additionally, the literature lacks a comprehensive examination of estimation performance for the likelihood-based general multi-state CTMC. Among studies attempting to assess the estimation, none have accounted for dependency among parameter estimates. The purpose of this research is twofold: (1) to develop a multivariate approach for assessing accuracy and precision for simulation studies (2) to add to the literature a comprehensive examination of the estimation of a general 3-state CTMC model. Simulation studies are conducted to analyze longitudinal data with a trinomial outcome using a CTMC with and without covariates. Measures of performance including bias, component-wise coverage probabilities, and joint coverage probabilities are calculated. An application is presented using Alzheimer's disease caregiver stress levels. Comparisons of joint and component-wise parameter estimates yield conflicting inferential results in simulations from models with and without covariates. In conclusion, caution should be taken when conducting simulation studies aiming to assess performance and choice of inference should properly reflect the purpose of the simulation.     

Peer 2 Peer: Efficacy of a Course-Based Peer Education Intervention to Increase Physical Activity Among College Students

Abstract

There are few physical activity (PA) interventions in higher education, and they have been only minimally effective. Objective: To determine if a course-based, peer education intervention was associated with increases in PA and physical fitness. Participants: Participants were 178 students enrolled in a personal health class during the 2007–2008 academic year. Methods: A quasi-experimental design was used to assess the effect of the intervention. Repeated measures analysis of covariance was employed to test the impact of the intervention on students’ PA, body composition, waist-to-hip ratio, cardiovascular fitness, flexibility, and muscular strength. Results: Women in the treatment group classified as “Inactive” at baseline increased PA, whereas “Inactive” control women had reductions in PA. Women in the treatment group who were “Active” at baseline reduced their waist-to-hip ratio and increased flexibility. There were no differences by treatment group among men. Conclusions: The intervention was effective in improving PA and physical fitness among college women.     

Subjective and Occupational Well-Being in a Sample of Mexican Workers

This article examines the well-being of workers, observing that subjective and occupational well-being are interrelated but independent dimensions and analyzing their interaction with their modulating factors. Specifically, the relationships between well-being and personal value structures are examined, hypothesizing that congruence between personal and socially predominant values improves the well-being of workers. The influence of various occupational and personal factors is also analyzed. We studied 209 workers of a multinational company in Mexico using different standardized questionnaires. The results demonstrate that subjective and occupational well-being are related but are independent variables influenced by differentiated variables. Specifically, the occupational wellbeing of workers is influenced by the nature of their work, whereas subjective well-being is affected by their social values and level of education. We present a model for the interaction of these variables and their consequences with the intention of the worker to stay with or leave the company. We discuss some practical issues raised by the study and make recommendations for future.     

Factors Affecting the LGBT Population When Choosing a Surrogate Decision Maker

ABSTRACT

For individuals in the marginalized population of lesbian, gay, bisexual, and trans- gender persons (LGBT), choosing a health care surrogate to make medical decisions is an emotionally challenging task. These decisions become more difficult when compounded by issues of discrimination, lack of legal and social support, varying levels of relationship commitment, and complications of disclosure to family and medical professionals. Limited research exists regarding the social, legal, medical, and familial environments that impact the choice of a surrogate decision maker for an LGBT individual. This systematic review examines 14 articles to identify factors influencing individual surrogate choice and existing gaps in the literature. To remedy current research limitations, future research recommendations address the areas of design, sampling, data collection, and data analysis within diverse subgroups of the LGBT population. This review further identifies related areas of service required by members of the LGBT population relative to diversity, demographics, and social, legal, medical, and familial environments influencing their choice of a surrogate decision maker.     

Media preferences of digital natives’ internal communication: A pilot study

Contemporary generations of employees are living in a completely different environment than previous generations, shaped by easier information gathering and access to knowledge. For employers, it raises an important question: what media preferences do digital natives have regarding internal communication channels? This study revealed that employees still favor traditional internal channels, in spite of a strong preference for social media in their private lives.     

Strategies in dynamic decision making - An experimental investigation of the rationality of decision behaviour

This paper is concerned with the question of how people tackle dynamic decision problems. It is on the interface between economics and psychology. Economic theory has a well-defined theory of how people should tackle such problems, but experimental evidence suggests that these are not empirically valid, and particularly that people find dynamic decision problems complex and cognitively demanding. Psychologists have long been aware of such issues and have developed a suite of theories to explain behaviour in such contexts, but these have been largely developed in a static context. This paper attempts to build a bridge between the two disciplines by exploring decision processes in a dynamic problem for which economic theory provides clear predictions. To aid us in this quest we use an experimental design which enables us to infer the decision rules that people are using. We identify a number of distinct decision heuristics, which could usefully be embodied into economic models of dynamic decision making.     

In sickness and in health: an examination of relationship status and health using data from the Canadian National Public Health Survey

There is an extensive literature suggesting that marriage confers benefits to both men and women in the form of increased earnings, better health and a longer life. Yet, where the focus is on health, most of this work has centered on one or two measures of health outcomes or on certain health behaviors such as smoking or alcohol use and has often failed to include those who cohabit as a separate relationship status. In this paper, we extend the research on the links between health and relationship status in three important ways. First, we consider a wide array of health indicators including self-reported health, chronic conditions, physical limitations, a measure of mental health, body mass index (BMI), and a number of health-related behaviors. Second, we use data from eight waves of the Canadian National Public Health Survey between 1994 and 2008 which allows us to estimate the effect of relationship status on health in a setting in which health insurance is not dependent on marriage. Third, we incorporate cohabitation as a separate relationship status. After controlling for time-invariant factors related to selection into and out of marriage, we find that marriage confers health benefits in the form of improved mental health, and lower levels of alcohol use. Marriage, however, is not without its cost. Similar to studies using U.S. data, marriage results in higher BMI, greater incidence of overweight and obesity and lower probabilities of regular exercise. These benefits and costs accrue to those who marry, and often to cohabiters.     

Differences in Tobacco Use Among Two-Year and Four-Year College Students in Minnesota

Abstract

Objective: This study compares tobacco use rates among two-year and four-year college students and explores the demographic variables that predicted that behavior. Participants: 9,931 students at 14 two-year and four-year colleges in Minnesota participated. Methods: Students at 11 schools completed an online survey, and students at 3 schools completed a paper survey in 2007. Results: After controlling for sex, age, ethnicity, relationship status, hours of work per week, and number of school credits, attending a two-year college predicted current and daily smoking (odds ratio [OR]) = 1.70, 95% confidence interval [CI] = 1.52–1.89; OR = 3.47, 95% CI = 2.94–4.11) and smokeless tobacco use (OR = 1.65, 95% CI = 1.32–2.06; OR = 1.64, 95% CI = 1.06–2.53). Conclusions: Although two-year college students comprise approximately two fifths of the college student population, surveys of college student tobacco use have focused nearly exclusively on four-year college students. Two-year college students should represent a priority population for tobacco control because attending a two-year college predicts increased tobacco use.     

The Influence of Commitment,Trust, Satisfaction,and Involvement on Donor Retention

Due to certain developments in the business of fundraising, there exists an increasing necessity to theoretically and empirically analyze donor behavior. This article examines donor retention from the donor’s point of view. It concretizes four antecedents and their relationships with one another. The influencing variables investigated are commitment, trust, satisfaction, and involvement. The empirical analysis conducted in Germany among donors of four representative social non-profit organizations shows that all variables have an influence on donor retention, although some of them only indirectly.