An RKHS framework for functional data analysis

Linear combinations of random variables play a crucial role in multivariate analysis. Two extension of this concept are considered for functional data and shown to coincide using the Loève–Parzen reproducing kernel Hilbert space representation of a stochastic process. This theory is then used to provide an extension of the multivariate concept of canonical correlation. A solution to the regression problem of best linear unbiased prediction is obtained from this abstract canonical correlation formulation. The classical identities of Lawley and Rao that lead to canonical factor analysis are also generalized to the functional data setting. Finally, the relationship between Fisher's linear discriminant analysis and canonical correlation analysis for random vectors is extended to include situations with function-valued random elements. This allows for classification using the canonical Y scores and related distance measures.     

Statistical Security for Social Security

The financial viability of Social Security, the single largest U.S. government program, depends on accurate forecasts of the solvency of its intergenerational trust fund. We begin by detailing information necessary for replicating the Social Security Administration's (SSA's) forecasting procedures, which until now has been unavailable in the public domain. We then offer a way to improve the quality of these procedures via age- and sex-specific mortality forecasts. The most recent SSA mortality forecasts were based on the best available technology at the time, which was a combination of linear extrapolation and qualitative judgments. Unfortunately, linear extrapolation excludes known risk factors and is inconsistent with long-standing demographic patterns, such as the smoothness of age profiles. Modern statistical methods typically outperform even the best qualitative judgments in these contexts. We show how to use such methods, enabling researchers to forecast using far more information, such as the known risk factors of smoking and obesity and known demographic patterns. Including this extra information makes a substantial difference. For example, by improving only mortality forecasting methods, we predict three fewer years of net surplus, $730 billion less in Social Security Trust Funds, and program costs that are 0.66% greater for projected taxable payroll by 2031 compared with SSA projections. More important than specific numerical estimates are the advantages of transparency, replicability, reduction of uncertainty, and what may be the resulting lower vulnerability to the politicization of program forecasts. In addition, by offering with this article software and detailed replication information, we hope to marshal the efforts of the research community to include ever more informative inputs and to continue to reduce uncertainties in Social Security forecasts.     

Potential impacts of emerald ash borer invasion on biogeochemical and water cycling in residential landscapes across a metropolitan region

Trees provide important ecological services in cities, yet the vulnerability of the urban forest to massive tree losses from pest outbreaks could threaten those services, with unknown environmental consequences. The outbreak of emerald ash borer is an imminent threat to the ash population in North America. In the Minneapolis?CSaint Paul, Minnesota, metropolitan area, ash trees are present in 50?% of residential landscapes in Ramsey and Anoka Counties. We used a large survey of household activities, a tree inventory, a Household Flux Calculator accounting tool, and a set of annual evapotranspiration measurements, to quantify the current carbon, nitrogen, and phosphorus storage in ash trees, the cycling of these elements, and the total evapotranspiration from ash trees in residential areas in the metropolitan region. Ash represented 6?% of the trees in residential areas and the removal of the entire ash population would correspondingly reduce net primary production and carbon sequestration by only a few percent and would have negligible effects on losses of nitrogen and phosphorus from residential landscapes. Similarly, the effects of ash loss on the hydrologic cycle would be minimal and would depend largely on management choices for the ground currently underneath ash tree canopies. Overall, the percentage change in biogeochemical and hydrological fluxes corresponded closely with the percent of the total urban tree population that was represented by ash, suggesting that areas with higher densities of ash would experience correspondingly larger effects. A hypothetical tree replacement scenario with similar broadleaf species was determined to be likely to re-establish the original biogeochemical and hydrological conditions once the replacement trees reach maturity.     

‘I Don't Just Want to Do It for Myself’: Diverse Pespectives on Being Successful at University by Social Work Students Who Speak English as an Additional Language

This article gives attention to furthering understandings about what being successful at university means to social work students, focusing on the perspectives of students who speak English as an additional language (EAL). It departs from approaches in the literature that focus on problematic aspects of teaching and learning. The article is informed by data from a small-scale focus group study of nine students from an undergraduate and a postgraduate social work programme in a South Australian university. Drawing on a methodological approach known as ‘Appreciative Inquiry’, students were asked how they conceptualise, experience and imagine success at university. The study found that students’ understandings of success are inextricably intertwined with their individual, family and community aspirations. These findings are discussed in the light of current dominant assumptions about the notion of success and possible directions for future research and implications for social work education.     

Negotiating disability and colonisation: the lived experience of Indigenous Australians with a disability

Disability among Indigenous Australians lies at a nexus between the ongoing impact of European settlement from 1788 and the social effects of living with a disability. Colonisation, with its political, social, economic and cultural concomitants, continues to impact on Indigenous experience, extending to the institutions and services concerned with disability. There is little attention paid to Indigenous Australian disability in general, and the need to decolonise disability has recently been emphasised. Ethnographic research in Brisbane, Australia among Indigenous people with a disability (mostly related to diabetes) confirms the ongoing impact of colonisation. While this experience pervades all aspects of their lives, it also moderates their experience of living with a disability in positive ways. However, while individuals can negotiate their personal experience of disability, the decolonisation of disability services presents challenges that need to be addressed.     

Children's Perceptions of Choice in Relation to their Play at Home,in the School Playground and at The Out‐of‐School Club

Choice is often presented as a defining feature of play and it has been argued that a perception of choice contributes to the developmental potential of play. This paper investigates children's self‐recorded levels of choice during play across three contexts—the home, the school playground and the out‐of‐school club. Children recorded their play activities across contexts using a structured diary technique. Findings based on 401 reported play episodes indicated that choice varied across contexts, according to the number of children involved and whether or not an adult was present. The findings are discussed in relation to theory, policy and professional practice.     

Neural Interaction Between Risk Sensitivity and Cognitive Control Predicting Health Risk Behaviors Among Late Adolescents

The developmental period of adolescence is characterized by increasing incidence of health risk behaviors (HRBs). Based on theoretical models that emphasize the moderating role of cognitive control, this study examined how neural correlates of cognitive control and risk sensitivity interact to predict HRBs among late adolescents (17–20 years). Neuroimaging data indicate that risk‐related hemodynamic activity in the anterior insula during anticipation of uncertain outcomes predicts HRBs among late adolescents exhibiting greater dorsal anterior cingulate cortex (dACC) activity during a cognitive interference task but not among late adolescents requiring less dACC activity. These results present neural evidence for a significant moderating effect of cognitive control on the link between risk sensitivity and HRBs among late adolescents.     

COMPETITIVE BALANCE MEASURES IN SPORTS LEAGUES: THE EFFECTS OF VARIATION IN SEASON LENGTH

Appropriate measurement of competitive balance is central to the economic analysis of professional sports leagues. We examine the distributional properties of the ratio of standard deviations (RSD) of points percentages, the most widely used measure of competitive balance in the sports economics literature, in comparison with other standard‐deviation‐based measures. Simulation methods are used to evaluate the effects of changes in season length on the distributions of competitive balance measures for different distributions of the strengths of teams in a league. The popular RSD measure performs as expected only in cases of perfect balance; if there is imbalance in team strengths, its distribution is sensitive to changes in season length. It is therefore not recommended for comparisons of competitive balance for different sports leagues with different numbers of teams and/or games played. (JEL L83, D63, C63)