Quantile Regression under Misspecification,with an Application to the U.S. Wage Structure

Quantile regression (QR) fits a linear model for conditional quantiles just as ordinary least squares (OLS) fits a linear model for conditional means. An attractive feature of OLS is that it gives the minimum mean‐squared error linear approximation to the conditional expectation function even when the linear model is misspecified. Empirical research using quantile regression with discrete covariates suggests that QR may have a similar property, but the exact nature of the linear approximation has remained elusive. In this paper, we show that QR minimizes a weighted mean‐squared error loss function for specification error. The weighting function is an average density of the dependent variable near the true conditional quantile. The weighted least squares interpretation of QR is used to derive an omitted variables bias formula and a partial quantile regression concept, similar to the relationship between partial regression and OLS. We also present asymptotic theory for the QR process under misspecification of the conditional quantile function. The approximation properties of QR are illustrated using wage data from the U.S. census. These results point to major changes in inequality from 1990 to 2000.     

Major Factors Influencing the Health Impacts from Controlling Air Pollutants with Nonlinear Chemistry: An Application to China

Predicting the human‐health effects of reducing atmospheric emissions of nitrogen oxide (NO_x) emissions from power plants, motor vehicles, and other sources is complex because of nonlinearity in the relevant atmospheric processes. We estimate the health impacts of changes in fine particulate matter (PM_2.5) and ozone concentrations that result from control of NO_x emissions alone and in conjunction with other pollutants in and outside the mega‐city of Shanghai, China. The Community Multiscale Air Quality (CMAQ) Modeling System is applied to model the effects on atmospheric concentrations of emissions from different economic sectors and geographic locations. Health impacts are quantified by combining concentration‐response functions from the epidemiological literature with pollutant concentration and population distributions. We find that the health benefits per ton of emission reduction are more sensitive to the location (i.e., inside vs. outside of Shanghai) than to the sectors that are controlled. For eastern China, we predict between 1 and 20 fewer premature deaths per year per 1,000 tons of NO_x emission reductions, valued at $300–$6,000 per ton. Health benefits are sensitive to seasonal variation in emission controls. Policies to control NO_x emissions need to consider emission location, season, and simultaneous control of other pollutants to avoid unintended consequences.     

‘This is a stage’: A study of public relations practitioners’ imagined online audiences

Public relations (PR) practitioners are among those cultural intermediaries who privilege symbols, products, and communication rituals in society. Through interviews (n = 26) and analysis of practitioners’ Twitter accounts, this study considers how members of this field identify their personal social networking site audiences and how these behaviors are implicated in the performance of their online identity. Findings indicate practitioners feel pressure to use personal social media in accordance with field-constrained norms and that an “occupational publicness” pressure requires them to be visible online outside of the workplace. The persistent specter of public criticism from audiences and the prioritizing of organizational interests above their own self-expression limits performances of PR practitioners’ authentic selves online.     

The Time-Course for the Capture and Hold of Visuospatial Attention by Fearful and Happy Faces

Fearful faces both capture our attention and hold it. However, little is known about the time-course for the capture and hold of spatial attention by fearful, and other emotional, faces. In three dot-probe studies we examined this time-course. Experiments 1 and 2 used fearful and neutral faces. In Experiment 1, dot-probe targets occurred 133, 266, and 532 ms post-face onset and in Experiment 2, dot-probe targets occurred 84, 168, 336, and 672 ms post-face onset. In Experiment 1, for both 133 and 266 ms conditions, reaction times were fastest for congruent trials and slowest for incongruent trials with reaction times for baseline trials falling between the two. The same pattern was found for the 84 and 168 ms conditions in Experiment 2. For the later time-points in both experiments there were no significant differences between conditions. To examine whether this time-course is unique to fearful faces, a third dot-probe experiment using time-points identical to Experiment 2 was conducted with happy and neutral faces. The results from Experiment 3 suggest that happy faces captured and held attention in the 168 and 336 ms conditions. Together, the results indicate that attention is captured and held by fearful faces at times earlier than approximately 300 ms, while happy faces also captured and held attention, but on a slightly different time-course from 168 to 336 ms.     

EXPONENTIAL‐GROWTH BIAS AND LIFECYCLE CONSUMPTION

Exponential‐growth bias (EGB) is the tendency for individuals to partially neglect compounding of exponential growth. We develop a model wherein biased agents misperceive the intertemporal budget constraint, and derive conditions for overconsumption and dynamic inconsistency. We construct an incentivized measure of EGB in a US‐representative population and find substantial bias, with approximately one third of subjects estimated as the fully biased type. The magnitude of the bias is negatively associated with asset accumulation, and does not respond to a simple graphical intervention.     

Longer Life and Population Growth

Enthusiasm about the prospect of large increases in human life expectancy is often dampened by fears that lower mortality will increase population size, hence population pressure. A simple mathematical model of life-cycle stretching demonstrates that if increased longevity is accompanied by later childbearing, a trend that is already underway, future declines in mortality will not increase population size.     

Global patterns of healthy life expectancy for older women

This paper focuses on patterns of healthy life expectancy for older women around the globe in the year 2000, and on the determinants of differences in disease and injury for older ages. Our study uses data from the World Health Organization for women and men in 191 countries. These data include a summary measure of population health, healthy life expectancy (HALE), which measures the number of years of life expected to be lived in good health, and a complementary measure of the loss of health (disability-adjusted life years or DALYs) due to a comprehensive set of disease and injury causes. We examine two topics in detail: (1) cross-national patterns of female-male differences in healthy life expectancy at age 60; and (2) identification of the major injury and disability causes of disability in women at older ages. Globally, the male-female gap is lower for HALE than for total life expectancy. The sex gap is highest for Russia (10.0 years) and lowest in North Africa and the Middle East, where males and females have similar levels of healthy life expectancy, and in some cases, females have lower levels of healthy life expectancy. We discuss the implications of the findings for international health policy.     

The Elite Illusion: Achievement Effects at Boston and New York Exam Schools

Parents gauge school quality in part by the level of student achievement and a school's racial and socioeconomic mix. The importance of school characteristics in the housing market can be seen in the jump in house prices at school district boundaries where peer characteristics change. The question of whether schools with more attractive peers are really better in a value‐added sense remains open, however. This paper uses a fuzzy regression‐discontinuity design to evaluate the causal effects of peer characteristics. Our design exploits admissions cutoffs at Boston and New York City's heavily over‐subscribed exam schools. Successful applicants near admissions cutoffs for the least selective of these schools move from schools with scores near the bottom of the state SAT score distribution to schools with scores near the median. Successful applicants near admissions cutoffs for the most selective of these schools move from above‐average schools to schools with students whose scores fall in the extreme upper tail. Exam school students can also expect to study with fewer nonwhite classmates than unsuccessful applicants. Our estimates suggest that the marked changes in peer characteristics at exam school admissions cutoffs have little causal effect on test scores or college quality.