An approach for finding fully Bayesian optimal designs using normal-based approximations to loss functions

The generation of decision-theoretic Bayesian optimal designs is complicated by the significant computational challenge of minimising an analytically intractable expected loss function over a, potentially, high-dimensional design space. A new general approach for approximately finding Bayesian optimal designs is proposed which uses computationally efficient normal-based approximations to posterior summaries to aid in approximating the expected loss. This new approach is demonstrated on illustrative, yet challenging, examples including hierarchical models for blocked experiments, and experimental aims of parameter estimation and model discrimination. Where possible, the results of the proposed methodology are compared, both in terms of performance and computing time, to results from using computationally more expensive, but potentially more accurate, Monte Carlo approximations. Moreover, the methodology is also applied to problems where the use of Monte Carlo approximations is computationally infeasible.     

The fertility integration of Mexican-Americans across generations: confronting the problem of the ‘third’ generation*

The manner in which ‘third generation’ Mexican-Americans are identified, predicated on self-reported ethnic identity rather than grandparental nativity, is imprecise and potentially confounded with later generations. This study examines the degree to which this imprecision accounts for the stagnation found in many past studies of integration, including fertility integration. We use data from the study Immigration and Intergenerational Mobility in Metropolitan Los Angeles (IIMMLA), which includes questions on grandparental nativity, to construct a better-defined third generation. When IIMMLA data are aggregated into the commonly measured third-plus generation, the findings show a pattern of slow intergenerational-fertility integration, similar to previous research using the Current Population Survey or other data with third-plus generation measures. However, when we consider a third generation identified by grandparental nativity, evidence emerges of a faster fertility decline, bringing the third generation's fertility more in line with the native-born population as a whole. The results suggest that conclusions about integration based on third-plus generation measures should be regarded with greater scepticism and support efforts to include in surveys questions on grandparental nativity to enable the isolation of a genuine third generation among ethnic groups with immigrant origins.     

Crown width models for woody plant species growing in urban areas of the U.S.

Urban Ecosystems - Crown widths of woody plant species growing in urban areas are of considerable importance as an overall indicator of health and also serve as an important factor for assessing...     

WHAT DO BICYCLE HELMET LAWS DO? EVIDENCE FROM CANADA

Twenty‐one states and the District of Columbia require youths to wear helmets when riding a bicycle, and there has been a push to extend such laws to adults. We provide new evidence on helmet laws by studying Canada using difference‐in‐differences models and restricted area‐identified public health survey data with information on cycling and helmet use for nearly 800,000 individuals from 1994 to 2014. We first confirm prior patterns from the United States that laws requiring youths to wear helmets significantly increased youth helmet use. We then provide the literature's first comprehensive evidence that “all‐age” bicycle helmet laws significantly increased both adult and youth helmet use by 50%–190% relative to pre‐reform levels, with larger effects for younger adults and less‐educated adults. All‐age helmet laws had modest effects at reducing cycling and increasing in‐home exercise during winter months among adults but did not meaningfully affect weight. Overall, our findings confirm that all‐age helmet laws can be effective at increasing population helmet use without significant unintended adverse health consequences. (JEL I18, I12, K32)     

Using national alcohol screening day to deliver personalized feedback: a pilot study

The current study tested the effectiveness of using National Alcohol Screening Day (NASD) to deliver personalized feedback via mail. At-risk NASD participants were assigned to either personalized or generic feedback conditions and attended a 4-week follow-up. Results failed to find any group differences on alcohol-related variables. However, participants in the personalized group reported a reduction in the maximum number of drinks consumed on one occasion. The personalized group also had a more accurate view of the amount of alcohol their peers consumed. NASD is a vehicle to efficiently deliver feedback to individuals about their alcohol use; however, more research is needed to determine the types of feedback that would be most effective.     

Supply Chain Sourcing in Remanufacturing Operations: An Empirical Investigation of Remake Versus Buy

Despite recent attention to closed‐loop supply chains and remanufacturing, there is scant information about what drives the re‐make versus buy decision for original equipment manufacturers (OEMs) engaging in remanufacturing. Based on the extant remanufacturing literature and transaction cost economics, we formulated hypotheses related to the drivers of in‐house versus contracted remanufacturing operations. The hypotheses were investigated via quantitative and qualitative data, thus offering a rich test of the formulated relationships. Consistent with the theory, the quantitative results showed that intellectual property, operational assets, and remanufacturing frequency are significant drivers of the re‐make versus buy decision. However, counter to the theory, the quantitative results did not support the significance of brand reputation, technological uncertainty, condition uncertainty, product complexity, and volume uncertainty. The qualitative results were used to enrich these findings by providing theoretical extensions and pragmatic insights of the remake versus buy decision in remanufacturing.     

Rational choices: an ecological approach

Theory and Decision - We address the oft-repeated criticism that the demands which the rational choice approach makes on the knowledge and cognition of a decision-maker (DM) are way beyond the...     

Activity of free-roaming domestic cats in an urban reserve and public perception of pet-related threats to wildlife in New Zealand

Urban Ecosystems - Across the globe there is an increasing number of initiatives promoting biodiversity in urban areas – both for the benefit of native wildlife and the people who live in...