Beta-Bernstein Smoothing for Regression Curves with Compact Support

ABSTRACT. The problem of boundary bias is associated with kernel estimation for regression curves with compact support. This paper proposes a simple and uni(r)ed approach for remedying boundary bias in non-parametric regression, without dividing the compact support into interior and boundary areas and without applying explicitly different smoothing treatments separately. The approach uses the beta family of density functions as kernels. The shapes of the kernels vary according to the position where the curve estimate is made. Theyare symmetric at the middle of the support interval, and become more and more asymmetric nearer the boundary points. The kernels never put any weight outside the data support interval, and thus avoid boundary bias. The method is a generalization of classical Bernstein polynomials, one of the earliest methods of statistical smoothing. The proposed estimator has optimal mean integrated squared error at an order of magnitude n ^−4/5, equivalent to that of standard kernel estimators when the curve has an unbounded support.     

Early Transition Stages and Heterogeneity in Criminal Careers among Young Offenders*

Dans cet article, nous examinons différents modèles de rapports avec les forces policières parmi des sous-populations hétérogènes de jeunes, dans les premiers stades de transition de leur carrière criminelle. Nous croyons que la recherche axée sur l'hétérogénéité et sur les premiers stades de la transition vers la criminalité peut nous renseigner sur les éléments de la dynamique comportementale - jusqu'ici ignorés - dans l'étude de l'apparition d'un comportement criminel et de sa persistance. À partir de données policières informatisées provenant d'une grande ville de l'ouest du Canada, nous utilisons certains modèles de survie basés sur des événements pour dégager des modèles d'apparition et de persistance de comportements criminels sur une période de six mois, dans les premiers rapports avec la police. Les résultats démontrent des modifications importantes à court terme dans le comportement criminel de sousgroupes de jeunes de niveaux différents. Certains semblent avoir un comportement criminel ponctuel, qu'ils abandonnent par la suite, tandis que d'autres continuent de se comporter en criminels, en augmentant la fréquence et le taux d'infractions. Toutefois, certains modèles hétérogènes existent au sein de ces sous-groupes de jeunes délin quants dans les premières phases de développement de la criminalité. We investigate distinctive patterns of police contacts among heterogeneous subpopulations of youths in the early transition stages of their criminal careers. We argue that research focussing upon heterogeneity and the initial transition stages of criminality can provide insights into behavioural dynamics previously overlooked in the study of the onset and development of criminal careers. Using computerized police archival data from a large western Canadian city, we employ event history survival models to estimate patterns of onset and persistence for delinquent careers over six-month intervals in the early stages of police contact. Our results provide strong evidence of meaningful short-term change in offending among multiple levels of youth subgroups. Some youths appear to offend only briefly and then desist, while others continue offending and at a higher rate. However, there also appear to be patterns of heterogeneity within as well as between these subgroups of young offenders during the early stages of criminal careers.     

Sample Splitting and Threshold Estimation

Threshold models have a wide variety of applications in economics. Direct applications include models of separating and multiple equilibria. Other applications include empirical sample splitting when the sample split is based on a continuously‐distributed variable such as firm size. In addition, threshold models may be used as a parsimonious strategy for nonparametric function estimation. For example, the threshold autoregressive model (TAR) is popular in the nonlinear time series literature. Threshold models also emerge as special cases of more complex statistical frameworks, such as mixture models, switching models, Markov switching models, and smooth transition threshold models. It may be important to understand the statistical properties of threshold models as a preliminary step in the development of statistical tools to handle these more complicated structures. Despite the large number of potential applications, the statistical theory of threshold estimation is undeveloped. It is known that threshold estimates are super‐consistent, but a distribution theory useful for testing and inference has yet to be provided. This paper develops a statistical theory for threshold estimation in the regression context. We allow for either cross‐section or time series observations. Least squares estimation of the regression parameters is considered. An asymptotic distribution theory for the regression estimates (the threshold and the regression slopes) is developed. It is found that the distribution of the threshold estimate is nonstandard. A method to construct asymptotic confidence intervals is developed by inverting the likelihood ratio statistic. It is shown that this yields asymptotically conservative confidence regions. Monte Carlo simulations are presented to assess the accuracy of the asymptotic approximations. The empirical relevance of the theory is illustrated through an application to the multiple equilibria growth model of Durlauf and Johnson (1995).     

Toleration or trust? Investigating the acceptance of ‘boat people’ among young Australians

There has been intense debate in Australia regarding how asylum seekers who arrive by boat should be treated. Some call for compassion towards those prepared to risk their lives to seek protection, whereas others believe ‘boat people’ should not be allowed into the country. This article uses data from a large representative sample of young people in Queensland, Australia, to understand the acceptance of asylum seekers by young people in Australia. The findings suggest that young Australians are more accepting than the Australian adult population. Several social and political background factors were also found to be associated with the belief that ‘boat people’ should be permitted into Australia. Fewer factors, however, are associated with the trust young Australians have in people from another country. This suggests that while some young Australians may believe boats carrying asylum seekers should not be turned away, fewer might be prepared to enter into trusting relationships with ‘boat people’ should they resettle in Australia.     

Welfare programs and the state economy

Welfare policy has been controversial and support is often drawn along political affiliation lines, the economic return of investment in welfare programs is frequently cited as a justification for new and expanded policies. To investigate the direct and indirect effects of welfare programs on economic performance, the authors develop a multilink approach, through employment and investment. The relationship is then tested with data from each of the United States from 1976 to 2006. Findings show welfare programs have no direct effect on a state's economy. Indirectly, welfare has a negative effect through investment, though the effect on employment is minimal.     

Leadership efficacy: Review and future directions

The concept of leader efficacy has received relatively little attention in the leadership literature. This is somewhat surprising given that effective leadership requires high levels of agency (i.e., deliberately or intentionally exerting positive influence) and confidence. This review uses existing theory and research on leader efficacy as a point of departure for proposing an expanded and multi-level framework for understanding the domain of leadership efficacy that includes leader, follower, and collective efficacies. The primary goals are to provide a conceptual framework to stimulate future theory and research on building efficacious leadership and to understand how such leadership develops and has implications for effective performance.     

Family Capital: Implications for Interventions with Families

Social capital has been extensively discussed in the literature as building blocks that individuals and communities utilize to leverage system resources. Similarly, some families also create capital, which can enable members of the family, such as children, to successfully negotiate the outside world. Families in poverty confront serious challenges in developing positive family capital, because of lack of resources. For those families that are successful in developing positive family capital, family capital can help to create positive outcomes for family interactions. Thus, family capital can provide information about opportunities, exert influence on agents who make decisions involving the actor, provide social credentials that indicate a connection to a social network, and reinforce the actor's identity and recognition, which maintains access and entitlement to these social resources.     

A Test of Excellent Leadership in Public Relations: Key Qualities,Valuable Sources,and Distinctive Leadership Perceptions

To better understand leadership in public relations and explore its value in successful communication management, this article captured the perceptions of mid- and senior-level public relations executives (N = 222) regarding the important qualities and dimensions of excellent leadership in the practice. According to study participants, strategic decision-making capability, problem-solving ability, and communication knowledge and expertise are the three most important qualities of excellent leadership. In addition, respondents said that on-the-job experiences, individual initiative and desire, and role models are the most valuable sources of leadership skills and development. About half of the respondents indicated that excellent leaders in public relations are different from leaders in other fields in three ways: They must hold a compelling vision for communication, possess comprehensive understanding of media and information systems, and effectively develop and implement strategic communication plans. Professional women and men in the study viewed excellent leadership in more or less similar ways. The study advances understanding of leadership in the field, which has been little explored in the public relations literature.