An Empirical Study of Statistical Properties of Variance Partition Coefficients for Multi-Level Logistic Regression Models

Partitioning the variance of a response by design levels is challenging for binomial and other discrete outcomes. Goldstein (2003 Goldstein , H. ( 2003 ). Multilevel Statistical Models. 3rd ed . London : Edward Arnold . [Google Scholar]) proposed four definitions for variance partitioning coefficients (VPC) under a two-level logistic regression model. In this study, we explicitly derived formulae for multi-level logistic regression model and subsequently studied the distributional properties of the calculated VPCs. Using simulations and a vegetation dataset, we demonstrated associations between different VPC definitions, the importance of methods for estimating VPCs (by comparing VPC obtained using Laplace and penalized quasilikehood methods), and bivariate dependence between VPCs calculated at different levels. Such an empirical study lends an immediate support to wider applications of VPC in scientific data analysis.     

On Tests for Group Variation With a Small to Moderate Number of Groups

This paper considers a family of penalized likelihood score tests for group variation. The tests can be indexed by a measure of degrees of freedom. At one extreme, with degrees of freedom one less than the number of groups, is the usual score test for a fixed effects alternative using indicator variables for the groups, while at the other extreme, in the limit as the degrees of freedom 0, is a test closely related to a score test based on a random effects alternative. Asymptotic power comparisons are made for the tests in the family. As would be expected, different members of the family are more efficient for different alternatives. Generally the tests with smaller degrees of freedom appear to have better power than the standard test for alternatives focusing on differences among the larger groups, and lower power for alternatives focusing on differences among the smaller groups. Simulations indicate the asymptotic approximation to the distribution performs better for the tests with small degrees of freedom.     

Principles for Conduct of Pest Risk Analyses: Report of an Expert Workshop

The North American Free Trade Agreement (NAFTA) and the General Agreement on Tariffs and Trade (GATT) have focused attention on risk assessment of potential insect, weed, and animal pests and diseases of livestock. These risks have traditionally been addressed through quarantine protocols ranging from limits on the geographical areas from which a product may originate, postharvest disinfestation procedures like fumigation, and inspections at points of export and import, to outright bans. To ensure that plant and animal protection measures are not used as nontariff trade barriers, GATT and NAFTA require pest risk analysis (PRA) to support quarantine decisions. The increased emphasis on PRA has spurred multiple efforts at the national and international level to design frameworks for the conduct of these analyses. As approaches to pest risk analysis proliferate, and the importance of the analyses grows, concerns have arisen about the scientific and technical conduct of pest risk analysis. In January of 1997, the Harvard Center for Risk Analysis (HCRA) held an invitation-only workshop in Washington, D.C. to bring experts in risk analysis and pest characterization together to develop general principles for pest risk analysis. Workshop participants examined current frameworks for PRA, discussed strengths and weaknesses of the approaches, and formulated principles, based on years of experience with risk analysis in other setting and knowledge of the issues specific to analysis of pests. The principles developed highlight the both the similarities of pest risk analysis to other forms of risk analysis, and its unique attributes.     

Thirty Years of Lottery Public Health Research: Methodological Strategies and Trends

Cognitive measurement techniques, such as self-reports of behavior and reaction time measures, largely dominate the field of psychological research. It is uncommon for researchers to examine a phenomenon of interest by observing actual behavior within natural settings. To illustrate the existence of this methodological trend for gambling research, this article reviews systematically selected samples of the peer-reviewed literature related to lottery gambling in general and the literature related to pathological gambling and lottery more specifically. The results indicate that self-report surveys dominate the extant lottery literature, and experimental investigations of video lottery terminal gambling supplement those papers. This landscape encourages researchers to expand their methodological approaches to the study of lottery gambling. Currently, we know more about what research participants tell us they do with respect to lottery gambling than we do about their real-life lottery gambling behavior.     

Compulsory Income Management in the Northern Territory – evaluating its impact

Australia has been experimenting with constraining the ways in which welfare recipients can spend their income support payments, limiting their ability to access cash and purchase some products. The policy objectives include to reduce spending on alcohol, gambling, pornography and tobacco in favour of meeting ‘basic’ family needs, especially for children, to limit the scope for financial harassment, encourage pro‐social behaviours, and build financial capabilities. In the logic of the programs these outcomes are expected to be manifest at the individual, family and community levels. The policy has primarily impacted on Indigenous Australians as a result of its geographic targeting, although a recent report has recommended a more stringent version of the program be introduced universally to all welfare recipients other than the aged. The largest of these experiments is ‘New Income Management’ in the Northern Territory, which has had more than 35,000 participants since its introduction in 2010. This article reports on the key findings of the major independent evaluation of New Income Management commissioned by the Australian Government.