Group and within-group variable selection for competing risks data

Variable selection in the presence of grouped variables is troublesome for competing risks data: while some recent methods deal with group selection only, simultaneous selection of both groups and within-group variables remains largely unexplored. In this context, we propose an adaptive group bridge method, enabling simultaneous selection both within and between groups, for competing risks data. The adaptive group bridge is applicable to independent and clustered data. It also allows the number of variables to diverge as the sample size increases. We show that our new method possesses excellent asymptotic properties, including variable selection consistency at group and within-group levels. We also show superior performance in simulated and real data sets over several competing approaches, including group bridge, adaptive group lasso, and AIC / BIC-based methods.     

Decreasing the Recent Immigrant Earnings Gap: The Impact of Canadian Credential Attainment

It is well documented that newly arrived immigrants face a significant earnings gap relative to native‐born workers. One way for new immigrants to improve their relative labour market position upon arrival in a host country is to improve their educational credentials. According to signalling theory, a host‐country credential should provide employers with a proxy for true productivity on the job, leading to higher earnings. Using data from a Canadian longitudinal survey, we employ longitudinal growth‐curve techniques to estimate the effect of receiving a Canadian educational credential on the income growth of racial‐minority recent immigrants compared to native‐born Canadians. The results indicate that the earnings gap between recent immigrants and native‐born Canadians is significantly reduced with the attainment of a Canadian educational credential.     

Adolescent egocentrism and indoor tanning: is the relationship direct or mediated?

This paper explored how imaginary audience and personal fable ideations contribute to adolescent indoor tanning intentions directly and indirectly through the way they shape pro-tanning attitude and association with peers who use tanning beds. Five hundred and ninety-five male (n = 207) and female (n = 387) adolescents, ranging in age from 11 to 19 (M = 16.87; SD = 1.34) years completed a cross-sectional survey. Measures included imaginary audience, personal fable (three dimensions: invulnerability, uniqueness, and omnipotence), pro-tanning attitude, association with peers who use tanning beds, and tanning bed use intentions. Bootstrapping analyses documented that imaginary audience ideations are indirectly associated with indoor tanning intentions through the mediation of pro-tanning attitude and association with peers who use tanning beds. Of the personal fable ideations, only invulnerability ideation is indirectly associated with indoor tanning intentions through the mediation of association with peers who use tanning beds. Design and evaluation of interventions and campaigns to reduce indoor tanning must be targeted to adolescents varying in imaginary audience ideations differently.     

Cross-country disparities in skill premium and skill acquisition

Skilled individuals are rewarded more in poor than in rich countries. Why aren't more individuals acquiring skills in poor countries? We document that the unemployment rate of the skilled net of that of the unskilled decreases with a country's level of development. Using a matching model of occupational choice and skill acquisition, we quantify the role of barriers to enter entrepreneurship for these unemployment rates, skill premium and acquisition. The cross-country correlation between skill premium and acquisition decreases by 45% when each country's gap to the US in the entrepreneurship barrier is decreased enough to even the unemployment differential.     

On the independence between two generalized second degree polynomial statistics and their covariance

The condition of independence between two generalized second degree polynomial statistics is worked out in this paper under the assumption that the covariance matrix of the underlying normal distribution may be singular. The covariance between two such forms is also worked out without the assumption of normality. The results are indicated in compact matrix form.     

Strategic Assessment Model (SAM): A Multiple Criteria Decision Support System for Evaluation of Strategic Alternatives*

The evaluation of strategic alternatives is a particularly difficult task. This difficulty is due to the complexities inherent in the evaluation process and the lack of structured information. The evaluation process must consider a multitude of relevant information from both the internal and external environments of the organization. Various analytical and normative models have helped decision makers utilize large volumes of information in strategic evaluation; however, most of these models have some limitations. We present a multiple criteria decision support system, called strategic assessment model (SAM), that addresses some of the limitations inherent in the existing models. SAM captures the decision maker's beliefs through a series of sequential, rational, and analytical processes. The environmental forces—decomposed into internal, task, general opportunities, and threats—are used along with the analytic hierarchy process (AHP), subjective probabilities, the entropy concept, and utility theory to enhance the decision maker's intuition in evaluating a set of strategic alternatives.