Importance sampling type estimators based on approximate marginal Markov chain Monte Carlo

We consider importance sampling (IS) type weighted estimators based on Markov chain Monte Carlo (MCMC) targeting an approximate marginal of the target distribution. In the context of Bayesian latent variable models, the MCMC typically operates on the hyperparameters, and the subsequent weighting may be based on IS or sequential Monte Carlo (SMC), but allows for multilevel techniques as well. The IS approach provides a natural alternative to delayed acceptance (DA) pseudo-marginal/particle MCMC, and has many advantages over DA, including a straightforward parallelization and additional flexibility in MCMC implementation. We detail minimal conditions which ensure strong consistency of the suggested estimators, and provide central limit theorems with expressions for asymptotic variances. We demonstrate how our method can make use of SMC in the state space models context, using Laplace approximations and time-discretized diffusions. Our experimental results are promising and show that the IS-type approach can provide substantial gains relative to an analogous DA scheme, and is often competitive even without parallelization.     

Measuring and framing support for universal basic income

We execute an original survey experiment to examine the extent and determinants of support for a nascent policy issue, universal basic income (UBI), in the American public. We explore the effects of how UBI is framed (either in the context of values or the context of policy), finding three key results. First, UBI is primarily a Democratic and liberal policy. Second, negative arguments against UBI move support for UBI more than positive arguments. Third, and surprisingly, respondents are equally affected by both policy-driven and value-driven arguments about UBI. In conclusion, an increase in messaging about UBI is likely to widen existing partisan differences in UBI support. These differences are unlikely to be won over by policy or values arguments.     

Topics in Microbial Risk Assessment: Dynamic Flow Tree Process

Microbial risk assessment is emerging as a new discipline in risk assessment. A systematic approach to microbial risk assessment is presented that employs data analysis for developing parsimonious models and accounts formally for the variability and uncertainty of model inputs using analysis of variance and Monte Carlo simulation. The purpose of the paper is to raise and examine issues in conducting microbial risk assessments. The enteric pathogen Escherichia coli O157:H7 was selected as an example for this study due to its significance to public health. The framework for our work is consistent with the risk assessment components described by the National Research Council in 1983 (hazard identification; exposure assessment; dose-response assessment; and risk characterization). Exposure assessment focuses on hamburgers, cooked a range of temperatures from rare to well done, the latter typical for fast food restaurants. Features of the model include predictive microbiology components that account for random stochastic growth and death of organisms in hamburger. For dose-response modeling, Shigella data from human feeding studies were used as a surrogate for E. coli O157:H7. Risks were calculated using a threshold model and an alternative nonthreshold model. The 95% probability intervals for risk of illness for product cooked to a given internal temperature spanned five orders of magnitude for these models. The existence of even a small threshold has a dramatic impact on the estimated risk.     

Time management as a moderator of relations between stressors and employee strain

The purpose of this study was to examine whether time management behaviours moderated relations between stressors (role conflict, role overload, work-family conflict, and family-work conflict) and strain, as measured by scores on the General Health Questionnaire. It was predicted that use of time management behaviours would be negatively associated with strain. These relations, however, were expected to be mediated by feelings of control over time. It was further predicted that the use of time management behaviours would attenuate stressor-strain relations. Data collected from 525 employed men and women indicated, as predicted, that use of time management behaviours was negatively associated with strain. These relations were partially mediated by feelings of control over time. Moderator tests failed to provide support for time management behaviour as a moderator of stressor-strain relations. Implications of findings are discussed and future directions for time management research are suggested.     

“A La Recherche Du” Quality of Life

This essay examines the stages of inquiry when we seek to formulate quality of life in an era before our own. There arises the question of the extent to which today’s formulation of quality of life can be applied to an era far removed from our own. Implicitly, there is the nature of the time interval, T₁···T_n, and the causal significance of intervening events. Data of a numerical sort can be hard to retrieve due to fires, wars, and mishandling. Quantitative data can be found in censuses and military records. Information in its raw form is referred to here as protodata. Figure 1 provides a schematic overview of the search for quality of life by subjective and objective modes of inquiry.     

Evaluation of single and mixed verbal operant arrangements for teaching mands and tacts

The purpose of this series of experiments was to evaluate the effects of mixed mand-tact arrangements on the acquisition of mands and tacts in preschool-aged children. In Experiment 1, the effects of three training arrangements (mand-only training, tact-only training, and mand-tact training) were investigated with 3 typically developing children. Rates of acquisition in single (mand-only and tact-only) versus mixed (mand-tact) presentation were comparable, in contrast to earlier investigations. Experiment 2 attempted to clarify the equivocal findings of Experiment 1 by directly replicating the Carroll and Hesse (1987) investigation with 2 typically developing children. Results again demonstrated no clear benefit of mixed verbal operant training on tact acquisition. In Experiment 3, these same arrangements were evaluated with a boy with autism and included assessments to determine that a relevant establishing operation was in effect prior to each mand training session. Experiment 3 again failed to demonstrate the facilitative effects of mand-tact training on the acquisition of mands or tacts. Taken together, the data from these three experiments fail to support the improved efficiency of mand-tact training suggested by prior studies. Findings are discussed in the context of future research investigating mixed verbal operant arrangements.     

Aboriginal and Torres Strait Islander employment policy and Welfare to Work: The Community Development Programme and the need for new narratives,new alliances and new institutions

The way Australian federal governments have approached Aboriginal and Torres Strait Islander employment and welfare policy over the last two decades has been a paradigmatic example of what not to do in policymaking. In the absence of effective engagement or consultation, a series of decisions under Coalition and Australian Labor Party governments have had a range of negative consequences for Aboriginal and Torres Strait Islander peoples. These changes – centred around the closure of the Community Development Employment Projects (CDEP) scheme and implementation of the Community Development Programme (CDP) – have resulted in increased unemployment, inadequate support for job creation, a dramatic over‐application of income penalties to social security recipients and reduced capacity in many community organisations. This article argues that these outcomes constitute policy failure, especially given that genuine engagement with Aboriginal and Torres Strait Islander people could have prevented many of these consequences. It then turns to an exploration of three ways in which Aboriginal and Torres Strait Islander people are responding to such policy failure: through promotion of new narratives, new alliances, and new institutions. The study concludes that while we should avoid “specious hope”, there is room for optimism in a renewed push for Aboriginal and Torres Strait Islander sovereignty.     

Book Review

Abstract

Kim Witte, Gary Meyer, and Dennis Martell. Effective Health Risk Messages: A Step-by-Step Guide: Thousand Oaks, CA: Sage; 2000. 216 pps; paper, $24.95, cloth, $64.95.     

College Women's Sexual Decision Making: Cognitive Mediation of Alcohol Expectancy Effects

Abstract

Objective: Alcohol has been linked to a variety of risky sexual practices, including inconsistent condom use. Due to the high rates of alcohol consumption among underage college women, greater understanding of the role of alcohol in young women's sexual decision making is warranted. Participants and Methods: Female underage (18- to 20-year-old) social drinkers (N = 94) participated in an experiment in which they projected themselves into a written hypothetical sexual situation with a new partner. One half of the situations portrayed alcohol consumption; one half did not involve alcohol consumption. Their appraisals of the situation's sexual potential, impelling and inhibiting cognitions, and sexual behavior intentions were assessed. Results: Results revealed that alcohol's expectancy effects on young women's unprotected sexual intentions were mediated by their cognitive appraisals of the situation. Conclusions: These findings indicate that alcohol expectancies and their influence on women's sexual decisions should be incorporated into sexual risk reduction efforts.