Accountability , Ability and Disability: Gaming the System

The past several years have been marked by a general trend towards increased high-stakes testing for students and schools and test-based school accountability systems. There are many potential school responses to testing programs. This paper investigates the potential that schools respond by gaming the system through reshaping the test pool. Using student-level panel data from six large counties in Florida, we study whether the introduction of the Florida Comprehensive Assessment Test in 1996 led schools to reclassify students as disabled and therefore ineligible to contribute to the school's aggregate test scores. Employing student-level fixed effect models and a series of secular trends as controls, we find that schools tend to reclassify low income and previously low performing students as disabled at significantly higher rates following the introduction of the testing regime. Moreover, these behaviors are concentrated among the low income schools most likely to be on the margin of failing the state's accountability system.

Rising Wage Inequality: The Role of Composition and Prices

During the early 1980s, earnings inequality in the U.S. labor market rose relatively uniformly throughout the wage distribution. But this uniformity gave way to a significant divergence starting in 1987, with upper-tail (90/50) inequality rising steadily and lower tail (50/10) inequality either flattening or compressing for the next 16 years (1987 to 2003). This paper applies and extends a quantile decomposition technique proposed by Machado and Mata (2005) to evaluate the role of changing labor force composition (in terms of education and experience) and changing labor market prices to the expansion and subsequent divergence of upper- and lower-tail inequality over the last three decades We show that the extended Machado-Mata quantile decomposition corrects shortcomings of the original Juhn-Murphy-Pierce (1993) full distribution accounting method and nests the kernel reweighting approach proposed by DiNardo, Fortin and Lemieux (1996). Our analysis reveals that shifts in labor force composition have positively impacted earnings inequality during the 1990s. But these compositional shifts have primarily operated on the lower half of the earnings distribution by muting a contemporaneous, countervailing lower-tail price compression. The steady rise of upper tail inequality since the late 1970s appears almost entirely explained by ongoing between-group price changes (particularly increasing wage differentials by education) and residual price changes.

The Polarization of the U.S. Labor Market

This paper analyzes a marked change in the evolution of the U.S. wage structure over the past fifteen years: divergent trends in upper-tail (90/50) and lower-tail (50/10) wage inequality. We document that wage inequality in the top half of distribution has displayed an unchecked and rather smooth secular rise for the last 25 years (since 1980). Wage inequality in the bottom half of the distribution also grew rapidly from 1979 to 1987, but it has ceased growing (and for some measures actually narrowed) since the late 1980s. Furthermore we find that occupational employment growth shifted from monotonically increasing in wages (education) in the 1980s to a pattern of more rapid growth in jobs at the top and bottom relative to the middles of the wage (education) distribution in the 1990s. We characterize these patterns as the %u201Cpolarization%u201D of the U.S. labor market, with employment polarizing into high-wage and low-wage jobs at the expense of middle-wage work. We show how a model of computerization in which computers most strongly complement the non-routine (abstract) cognitive tasks of high-wage jobs, directly substitute for the routine tasks found in many traditional middle-wage jobs, and may have little direct impact on non-routine manual tasks in relatively low-wage jobs can help explain the observed polarization of the U.S. labor market.

Trends in U. S. Wage Inequality: Re-Assessing the Revisionists

A large literature documents a substantial rise in U. S. wage inequality and educational wage differentials over the past several decades and finds that these trends can be primarily accounted for by shifts in the supply of and demand for skills reinforced by the erosion of labor market institutions affecting the wages of low- and middle-wage workers. Drawing on an additional decade of data, a number of recent contributions reject this consensus to conclude that (1) the rise in wage inequality was an “episodic” event of the first-half of the 1980s rather than a "secular” phenomenon, (2) this rise was largely caused by a falling minimum wage rather than by supply and demand factors; and (3) rising residual wage inequality since the mid-1980s is explained by confounding effects of labor force composition rather than true increases in inequality within detailed demographic groups. We reexamine these claims using detailed data from the Current Population Survey and find only limited support. Although the growth of overall inequality in the U. S. slowed in the 1990s, upper tail inequality rose almost as rapidly during the 1990s as during the 1980s. A decomposition applied to the CPS data reveals large and persistent rise in within-group earnings inequality over the past several decades, controlling for changes in labor force composition. While changes in the minimum wage can potentially account for much of the movement in lower tail earnings inequality, strong time series correlations of the evolution of the real minimum wage and upper tail wage inequality raise questions concerning the causal interpretation of such relationships. We also find that changes in the college/high school wage premium appear to be well captured by standard models emphasizing rapid secular growth in the relative demand for skills and fluctuations in the rate of growth of the relative supply of college workers – though these models do not accurately predict the slowdown in the growth of the college/high-school gap during the 1990s. We conclude that these patterns are not adequately explained by either a ‘unicausal’ skill-biased technical change explanation or a revisionist hypothesis focused primarily on minimum wages and mechanical labor force compositional effects. We speculate that these puzzles can be partially reconciled by a modified version of the skill-biased technical change hypothesis that generates a polarization of skill demands.

Trends in U.S. Wage Inequality: Re-Assessing the Revisionists

A recent "revisionist " literature characterizes the pronounced rise in U.S. wage inequality since 1980 as an "episodic " event of the first-half of the 1980s driven by non-market factors (particularly a falling real minimum wage) and concludes that continued increases in wage inequality since the late 1980s substantially reflect the mechanical confounding effects of changes in labor force composition. Analyzing data from the Current Population Survey for 1963 to 2005, we find limited support for these claims. The slowing of the growth of overall wage inequality in the 1990s hides a divergence in the paths of upper-tail (90/50) inequality -- which has increased steadily since 1980, even adjusting for changes in labor force composition -- and lower tail (50/10) inequality, which rose sharply in the first-half of the 1980s and plateaued or contracted thereafter. Fluctuations in the real minimum wage are not a plausible explanation for these trends since the bulk of inequality growth occurs above the median of the wage distribution. Models emphasizing rapid secular growth in the relative demand for skills -- attributable to skill-biased technical change -- and a sharp deceleration in the relative supply of college workers in the 1980s do an excellent job of capturing the evolution of the college/high-school wage premium over four decades. But these models also imply a puzzling deceleration in relative demand growth for college workers in the early 1990s, also visible in a recent "polarization" of skill demands in which employment has expanded in high-wage and low-wage work at the expense of middle-wage jobs. These patterns are potentially reconciled by a modified version of the skill-biased technical change hypothesis that emphasizes the role of information technology in complementing abstract (high-education) tasks and substituting for routine (middle-education) tasks.

Rising Wage Inequality: The Role of Composition and Prices

During the early 1980s, earnings inequality in the U. S. labor market rose relatively uniformly throughout the wage distribution. But this uniformity gave way to a significant divergence starting in 1987, with upper-tail (90/50) inequality rising steadily and lower tail (50/10) inequality either flattening or compressing for the next 16 years (1987 to 2003). This paper applies and extends a quantile decomposition technique proposed by Machado and Mata (2005) to evaluate the role of changing labor force composition (in terms of education and experience) and changing labor market prices to the expansion and subsequent divergence of upper- and lower-tail inequality over the last three decades We show that the extended Machado-Mata quantile decomposition corrects shortcomings of the original Juhn-Murphy-Pierce (1993) full distribution accounting method and nests the kernel reweighting approach proposed by DiNardo, Fortin and Lemieux (1996). Our analysis reveals that shifts in labor force composition have positively impacted earnings inequality during the 1990s. But these compositional shifts have primarily operated on the lower half of the earnings distribution by muting a contemporaneous, countervailing lower-tail price compression. The steady rise of upper tail inequality since the late 1970s appears almost entirely explained by ongoing between-group price changes (particularly increasing wage differentials by education) and residual price changes.

The shock process and light element production in supernovae envelopes

Detailed hydrodynamic modeling of the passage of supernova shocks through the hydrogen envelopes of blue and red progenitor stars was carried out to explore the sensitivity to model conditions of light element production (specifically Li-7 and B-11) which was noted by Dearborn, Schramm, Steigman and Truran (1989) (DSST). It is found that, for stellar models with M is less than or approximately 100 M solar mass, current state of the art supernova shocks do not produce significant light element yields by hydrodynamic processes alone. The dependence of this conclusion on stellar models and on shock strengths is explored. Preliminary implications for Galactic evolution of lithium are discussed, and it is suspected that intermediate mass red giant stars may be the most consistent production site for lithium

Legal capacities required for prevention and control of noncommunicable diseases

Law lies at the centre of successful national strategies for prevention and control of noncommunicable diseases. By law we mean international agreements, national and subnational legislation, regulations and other executive instruments, and decisions of courts and tribunals. However, the vital role of law in global health development is often poorly understood, and eclipsed by other disciplines such as medicine, public health and economics. This paper identifies key areas of intersection between law and noncommunicable diseases, beginning with the role of law as a tool for implementing policies for prevention and control of leading risk factors. We identify actions that the World Health Organization and its partners could take to mobilize the legal workforce, strengthen legal capacity and support effective use of law at the national level. Legal and regulatory actions must move to the centre of national noncommunicable disease action plans. This requires high-level leadership from global and national leaders, enacting evidence-based legislation and building legal capacities