Semiparametric Estimation of a Proportional Hazard Model with Unobserved Heterogeneity

The proportional hazard model with unobserved heterogeneity gives the hazard function of a random variable conditional on covariates and a second random variable representing unobserved heterogeneity. This paper shows how to estimate the baseline hazard function and the distribution of the unobserved heterogeneity nonparametrically. The baseline hazard function and heterogeneity distribution are assumed to satisfy smoothness conditions but are not assumed to belong to known, finite-dimensional, parametric families. Existing estimators assume that the baseline hazard function or heterogeneity distribution belongs to a known parametric family. Thus, the estimators presented here are more general than existing ones.     

Contract Length as Risk Management When Labor is not Homogeneous

This paper examines the choice of contract length for workers who possess unique skills. Uncertainty, facing both the worker and the firm, creates an incentive to reallocate risk. The uncertainty arises from two sources: variation in the market value of the worker's human capital and fluctuation in the worker's physical production. Long‐term contracts are typically modeled as compensating wage differentials, or as a solution to the problem of asymmetric information. This paper develops a model proposing more complex behavior in the reallocation of risk between the contracting parties. The model shows that long‐term labor contracts are most likely to be observed when price uncertainty in the labor market exceeds the worker's productive uncertainty.     

Academic Autonomy and Freedom under Pressure: Severely Limited,or Alive and Kicking?

Academic freedom and the autonomy of academic institutions (their freedom from outside interference) are core values in contemporary academic life. This article outlines changes that have taken place in the last few decades that impact academic freedom and autonomy to at least some degree. These include the increasing catering by universities to stake-holders in the environment, increasing professionalization of university administrations, an evolving pattern of broadening authority over internal university decision-making, and an increasing attention to student (i.e. customer) needs. Two case studies -- one of recent decisions in the University of California system and the other at the University of Oslo -- illustrate the theoretical points in the article and point to the need to know a lot more about academic autonomy and academic freedom, especially in an environment of changing management practices and scarce resource bases for many institutions. The cases were selected because of the authors’ familiarity with them and are examples meant to illuminate some of the challenges and complexities inherent in the phenomena and to inspire further research on academic freedom and autonomy utilizing the instrumental and institutional perspectives from organization theory that are the core of our theoretical analysis.     

Middle-Range Future Claims: Constructing the Near-Future Consequences of COVID-19

The extraordinary social and economic impact of the COVID-19 pandemic has generated many claims about the middle-range future—the period beginning in the late summer or early fall of 2020 and projected to last for some months or years. This paper surveys those assertions and seeks to explain the factors that led to them. Exploring questions about future claims can expand the scope of social problems theory.     

Pilot study of a Web-based acceptance and commitment therapy intervention for university students to reduce academic procrastination

Objective: This pilot study pursued two aims. The first was to investigate the feasibility and acceptability of a Web-based acceptance and commitment therapy (ACT) intervention to reduce academic procrastination among university students. The second aim was to test the effectiveness of the intervention on procrastination and committed actions. Participants: The sample was comprised of Canadian university students (n?=?36) that participated in the intervention between September 2016 and April 2017. Methods: The study relied on a prepost research design. Results: The intervention appears feasible, acceptable, and valuable to students. A significant reduction in procrastination and a significant improvement in committed actions were found between pre and postintervention. The effect sizes for these results were medium. Conclusions: Results provide preliminary support for the feasibility and effectiveness of a Web-based ACT intervention for academic procrastination. Results also highlight some aspects that need to be improved for further development.     

Symposium: Neuroergonomics, technology, and cognition

This symposium describes collaborative research on neuroergonomics, technology, and cognition being conducted at George Mason University and the US Air Force Research Laboratory (AFRL) as part of the Center of Excellence in Neuroergonomics, Technology, and Cognition (CENTEC). Six presentations describe the latest developments in neuroergonomics research conducted by CENTEC scientists. The individual papers cover studies of: (1) adaptive learning systems; (2) neurobehavioral synchronicity during team performance; (3) genetics and individual differences in decision making; (4) vigilance and mindlessness; (5) interruptions and multi-tasking; and (6) development of a simulation capability that integrates measures across these domains and levels of analysis.     

Development of Sexual Expectancies among Adolescents: Contributions by Parents,Peers and the Media

To expand the scant research on sexual expectancies development among non–sexually active adolescents, we examined the relationship between adolescents' exposure to four socializing agents—mother/female guardian, father/male guardian, peers, and television programs with high sexual content—and their endorsement of four sexual expectancies: social benefit, pleasure, social risk, and health risk. Data are from Waves 2 and 3 of a three-wave annual longitudinal study conducted among California adolescents, the majority of whom were not sexually active (N = 914, 84%). Structural equation models were conducted to examine cross-sectional and longitudinal associations between the socializing agents and the sexual expectancies. Cross-sectional results indicate associations between peer sexual communication and social benefit, pleasure, and social risk expectancies. A positive association was found between exposure to music videos and social benefit expectancies, and a negative association was found between exposure to music videos and health risk expectancies. Longitudinal results suggest that communication with peers positively predicted pleasure expectancies and negatively predicted social risk expectancies. No other socializing agents were associated with any sexual expectancies. An invariance test found that significant correlations were similar across the different age groups. Results suggest that efforts to support positive sexual decision making among non–sexually active adolescents should target peer sexual communication.     

Evaluating multi-regional population projections with Taylor’s law of mean–variance scaling and its generalisation

Organisations that develop demographic projections usually propose several variants with different demographic assumptions. Existing criteria for selecting a preferred projection are mostly based on retrospective comparisons with observations, and a prospective approach is needed. In this work, we use the mean–variance scaling (spatial variance function) of human population densities to select among alternative demographic projections. We test against observed and projected Norwegian county population density using two spatial variance functions, Taylor’s law (TL) and its quadratic generalisation, and compare each function’s parameters between the historical data and six demographic projections, at two different time scales (long term: 1978–2010 vs. 2011–2040; and short term: 2006–2010 vs. 2011–2015). We find that short-term projections selected by TL agree more accurately than the other projections with the recent county density data and reflect the current high rate of international migration to and from Norway. The variance function method implemented here provides an empirical test of an ex ante approach to evaluating short-term human population projections.