Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human–natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.

Since the Coleman Report, many have questioned whether public school spending affects student outcomes. The school finance reforms that began in the early 1970s and accelerated in the 1980s caused dramatic changes to the structure of K–12 education spending in the United States. To study the effect of these school finance reform–induced changes in public school spending on long-run adult outcomes, we link school spending and school finance reform data to detailed, nationally representative data on children born between 1955 and 1985 and followed through 2011. We use the timing of the passage of court-mandated reforms and their associated type of funding formula change as exogenous shifters of school spending, and we compare the adult outcomes of cohorts that were differentially exposed to school finance reforms, depending on place and year of birth. Event study and instrumental variable models reveal that a 10% increase in per pupil spending each year for all 12 years of public school leads to 0.31 more completed years of education, about 7% higher wages, and a 3.2 percentage point reduction in the annual incidence of adult poverty; effects are much more pronounced for children from low-income families. Exogenous spending increases were associated with notable improvements in measured school inputs, including reductions in student-to-teacher ratios, increases in teacher salaries, and longer school years.

We investigate institutional explanations for Congress’s choice to fragment statutory frameworks for policy implementation.  We argue that divided party government, which fuels legislative-executive conflict over control of the bureaucracy, motivates Congress to fragment implementation power as a strategy to enhance its control over implementation.  We develop a novel measure of fragmentation in policy implementation, collect data on it over the period 1947 to 2008, and test hypotheses linking separation of powers structures to legislative design of fragmented implementation power.  We find that divided party government is powerfully associated with fragmentation in policy implementation, and that this association contributed to the long-run growth of fragmentation in the post-war U.S.  We further find that legislative coalitions are more likely to fragment implementation power in the face of greater uncertainty about remaining in the majority.

A small group of individuals with mental illness is repeatedly involved in violence. Little is known about how often and how consistently these high-risk individuals experience delusions or hallucinations just before a violent incident. To address these questions, data from the MacArthur Violence Risk Assessment Study was used to identify 305 violent incidents associated with 100 former inpatients with repeated violence (representing 50% of incidents and 9% of participants), and test whether psychosis-preceded incidents cluster within individuals. Results indicated that (a) psychosis immediately preceded 12% of incidents, (b) individuals were “fairly” consistent in their violence type (ICC = .42), and (c) those with exclusively “non-psychosis-preceded” violence (80%) could be distinguished from a small group who also had some psychosis-preceded violence (20%). These findings suggest that psychosis sometimes foreshadows violence for a fraction of high-risk individuals, but violence prevention efforts should also target factors like anger control and social deviance.

The past several years have seen a surge of interest in using risk assessment in criminal sentencing, both to reduce recidivism by incapacitating or treating high-risk offenders and to reduce prison populations by diverting low-risk offenders from prison. We begin by sketching jurisprudential theories of sentencing, distinguishing those that rely on risk assessment from those that preclude it. We then characterize and illustrate the varying roles that risk assessment may play in the sentencing process. We clarify questions regarding the various meanings of “risk” in sentencing and the appropriate time to assess the risk of convicted offenders. We conclude by addressing four principal problems confronting risk assessment in sentencing: conflating risk and blame, barring individual inferences based on group data, failing adequately to distinguish risk assessment from risk reduction, and ignoring whether, and if so, how, the use of risk assessment in sentencing affects racial and economic disparities in imprisonment.