Have Americans' Attitudes Become More Polarized?—An Update*

Objective. I examine polarization in public opinion using the method of DiMaggio, Evans, and Bryson (DEB) (1996), but go further than DEB by using newly available years of survey data. Method. Like DEB, I derive aggregate distributional parameters for social groups in each year of the surveys, and then regress the year of the surveys on each parameter. Results. As in DEB's original paper, there is little evidence of general polarization in attitudes between the early 1970s and today. However, while DEB found some evidence that polarization in the public may be the result of polarization in our political system, with the additional years of data this conclusion is inescapable. Conclusions. Although political scientists have recently found polarization among our elected officials on economic issues, it seems clear that members of the public who identify with the partisan labels of our political system are becoming polarized on moral issues.     

Factors Associated with the Enactment of Safety Belt and Motorcycle Helmet Laws

It has been shown that road safety laws, such as motorcycle helmet and safety belt laws, have a significant effect in reducing road fatalities. Although an expanding body of literature has documented the effects of these laws on road safety, it remains unclear which factors influence the likelihood that these laws are enacted. This study attempts to identify the factors that influence the decision to enact safety belt and motorcycle helmet laws. Using panel data from 31 countries between 1963 and 2002, our results reveal that increased democracy, education level, per capita income, political stability, and more equitable income distribution within a country are associated with the enactment of road safety laws.     

Bayesian ikference procedures derived via the concept of relative surprise

We consider the problem of deriving Bayesian inference procedures via the concept of relative surprise. The mathematical concept of surprise has been developed by I.J. Good in a long sequence of papers. We make a modification to this development that permits the avoidance of a serious defect; namely, the change of variable problem. We apply relative surprise to the development of estimation, hypothesis testing and model checking procedures. Important advantages of the relative surprise approach to inference include the lack of dependence on a particular loss function and complete freedom to the statistician in the choice of prior for hypothesis testing problems. Links are established with common Bayesian inference procedures such as highest posterior density regions, modal estimates and Bayes factors. From a practical perspective new inference procedures arise that possess good properties.     

Mathematical modeling in sociology: An exemplar (1)

This paper describes the method of differential equation modeling. To illustrate its application in sociology, a theory of the contribution of income to occupational prestige is developed and tested. The importance of theoretical foundations and inference therefrom is then discussed with a view to providing a model for teaching and the initiation of research.     

Accidental fatalities in transport

Summary. The paper considers accidents on the different modes of transport. Accidents have many kinds of unwanted effects, though the paper focuses on just one: accidental fatalities. The paper reviews the main official sources of accident data and considers the use of past accident data. It then offers data and discussion on the numbers of accidental fatalities per year, passenger fatality rates, major accidents and the fatalities imposed by transport on third parties. The paper concludes with a brief discussion of communicating these results.     

Migration and health

Investigation of migration and health often forces us to acknowledge that the types of migration (international, internal, and residential) interact with each other as well as other population parameters such as the age/sex structure, sexual activity, fertility, mortality, and family structure. Research on migration is often obscured by these interactions. In fact, the adoption of a health perspective in the design of migration research represents a substantial improvement over traditional approaches that are based on distinctions among the various types of population movement. This is because a health perspective treats population movement as a dynamic process by which individuals are related to specific locations by reason of their participation in human networks. In other words, migration is regarded as a human process rather than a discrete event, and accordingly, it becomes less important to describe the individual's involvement with human networks and the institutions sustaining them. The use of a health perspective in migration research often calls our attention to the ways in which the types of migration are interconnected. For example, a migrant from Mexico might exhibit considerable internal mobility and may circulate between Mexico might exhibit considerable internal mobility and may circulate between Mexico and the US over several years until he develops enough contacts in the US to settle in a particular community in which his personal contact with human networks and place-specific institutions are conducive to settlement. Through him, family members may attach to the community. In the process, they all encounter health risks, make demands on the health care system, change the demographic/health characteristics of both sending and receiving places, sometimes act as transmitting agents of disease to those with whom they interact and, undergo changes in their levels of personal development and well-being. A research perspective that investigates these processes will consider all of the types of movement and characterize them as dynamic processes rather than as discrete events. The articles in this issue all touch on the ways in which migration can affect the health of migrants, and show the circle range of ways migration and health are interrelated. A special introductory note also suggests Acquired Immunodeficiency Syndrome (AIDS) should receive special attention in the study of this interrelationship. The uneven distribution of AIDS is heightening concern about the health implications for receiving countries.     

Duration Adjustment of Acute Exposure Guideline Level Values for Trichloroethylene Using a Physiologically-Based Pharmacokinetic Model

Acute Exposure Guideline Level (AEGL) recommendations are developed for 10-minute, 30-minute, 1-hour, 4-hours, and 8-hours exposure durations and are designated for three levels of severity: AEGL-1 represents concentrations above which acute exposures may cause noticeable discomfort including irritation; AEGL-2 represents concentrations above which acute exposure may cause irreversible health effects or impaired ability to escape; and AEGL-3 represents concentrations above which exposure may cause life-threatening health effects or death. The default procedure for setting AEGL values across durations when applicable data are unavailable involves estimation based on Haber's rule, which has an underlying assumption that cumulative exposure is the determinant of toxicity. For acute exposure to trichloroethylene (TCE), however, experimental data indicate that momentary tissue concentration, and not the cumulative amount of exposure, is important. We employed an alternative approach to duration adjustments in which a physiologically-based pharmacokinetic (PBPK) model was used to predict the arterial blood concentrations [TCE(a)] associated with adverse outcomes appropriate for AEGL-1, -2, or -3-level effects. The PBPK model was then used to estimate the atmospheric concentration that produces equivalent [TCE(a)] at each of the AEGL-specific exposure durations. This approach yielded [TCE(a)] values of 4.89 mg/l for AEGL-1, 18.7 mg/l for AEGL-2, and 310 mg/l for AEGL-3. Duration adjustments based on equivalent target tissue doses should provide similar degrees of toxicity protection at different exposure durations.     

The impact of resources and family-level cultural practices on immigrant women’s workforce participation

This article aims to assess the extent to which women's labor force participation reflects culturally or situationally induced family strategies above and beyond the well-known effects of opportunities and constraints associated with education and the life cycle. We focus particularly on women immigrants from the former Yugoslavia in Australia, and explore the family strategies by comparing the Yugoslav women systematically to immigrant women from other parts of the Mediterranean world and to immigrant women from other parts of the Slavic world. To this end, we use data from the one percent public use sample of individual records of the 1981 Australian Census. We find that the labor force particiaation patterns of immigrant women from the former Yugoslavia are more shaped by education and less shaped by the life course than is true of other groups, although the life course matters for all of them. Indeed, in the impact of education on labor force they closely resemble the Eastern Europeans across most of the range of education. But in the impact of life cycle stage on participation they more closely resemble the Greeks and the Italians. This emphasizes how important it is that statistical agencies release data at the greatest possible level of detail: A country may belong in one group for some purposes, but in a different group for other purposes. We assess a number of explanations for birthplace differences in participation patterns, and find most wanting. We suggest that they may reflect culturally conditioned intergenerational wealth flows and patterns of time investiment in children and the elderly. M.D.R. Evans's research focuses on comparative, international analyses of stratification, ethnicity, culture, and gender. Her book, Prejudice or Productivity, is forthcoming from Westview Press.     

Testing for serial correlation in the presence of dynamic heteroscedasticity

Standard serial correlation tests are derived assuming that the disturbances are homoscedastic, but this study shows that asympotic critical values are not accurate when this assumption is violated. Asymptotic critical values for the ARCH(2)-corrected LM, BP and BL tests are valid only when the underlying ARCH process is strictly stationary, whereas Wooldridge's robust LM test has good properties overall. These tests exhibit similar bahaviour even when the underlying process is GARCH (1,1). When the regressors include lagged dependent variables, the rejection frequencies under both the null and alternative hypotheses depend on the coefficientsof the lagged dependent variables and the other model parameters. They appear to be robust across various disturbance distributions under the null hypothesis.