We propose a dynamic framework to study the value of medical innovation in the context of infectious disease. We apply our framework to evaluate an HIV treatment breakthrough known as HAART. The model captures how, in lowering both the expected cost and likelihood of HIV infection, HAART reduced the implicit price of risky sex. Forward-looking agents responded by optimally shifting their behaviour. The model also imposes equilibrium constraints, explicitly capturing how optimal shifts in behaviour affect equilibrium choices by changing both infection probabilities and the ease of finding partners willing to engage in risky sex. Using the estimated model, we conduct counterfactual simulations to compute the value of HAART from the perspective of uninfected agents. This includes the option value of the innovation along with value accruing from changes in sex behaviour in response to HAART introduction. We also calculate the added value of a fully functional vaccine from the perspective of both infected and uninfected agents, where infected agents benefit from a vaccine due to resulting shifts in market equilibrium.

We link daily air pollution exposure to measures of contemporaneous health for communities surrounding the twelve largest airports in California. These airports are some of the largest sources of air pollution in the US, and they experience large changes in daily air pollution emissions depending on the amount of time planes spend idling on the tarmac. Excess airplane idling, measured as residual daily taxi time, is due to network delays originating in the Eastern US. This idiosyncratic variation in daily airplane taxi time significantly impacts the health of local residents, largely driven by increased levels of carbon monoxide (CO) exposure. We use this variation in daily airport congestion to estimate the population dose-response of health outcomes to daily CO exposure, examining hospitalization rates for asthma, respiratory, and heart-related emergency room admissions. A one standard deviation increase in daily pollution levels leads to an additional $540 thousand in hospitalization costs for respiratory and heart-related admissions for the 6 million individuals living within 10 km (6.2 miles) of the airports in California. These health effects occur at levels of CO exposure far below existing Environmental Protection Agency mandates, and our results suggest there may be sizable morbidity benefits from lowering the existing CO standard.

We investigate a simple dynamical model for the systemic risk caused by the use of Value-at-Risk, as mandated by Basel II. The model consists of a bank with a leverage target and an unleveraged fundamentalist investor subject to exogenous noise with clustered volatility. The parameter space has three regions: (i) a stable region, where the system has a fixed point equilibrium; (ii) a locally unstable region, characterized by cycles with chaotic behavior; and (iii) a globally unstable region. A calibration of parameters to data puts the model in region (ii). In this region there is a slowly building price bubble, resembling the period prior to the Global Financial Crisis, followed by a crash resembling the crisis, with a period of approximately 10–15 years. We dub this the Basel leverage cycle. To search for an optimal leverage control policy we propose a criterion based on the ability to minimize risk for a given average leverage. Our model allows us to vary from the procyclical policies of Basel II or III, in which leverage decreases when volatility increases, to countercyclical policies in which leverage increases when volatility increases. We find the best policy depends on the market impact of the bank. Basel II is optimal when the exogenous noise is high, the bank is small and leverage is low; in the opposite limit where the bank is large and leverage is high the optimal policy is closer to constant leverage. In the latter regime systemic risk can be dramatically decreased by lowering the leverage target adjustment speed of the banks. While our model does not show that the financial crisis and the period leading up to it were due to VaR risk management policies, it does suggest that it could have been caused by VaR risk management, and that the housing bubble may have just been the spark that triggered the crisis.

Over the last two decades, share repurchases have emerged as the dominant payout channel, offering a more flexible means of returning excess cash to investors. However, little is known about the costs associated with payout-related financial flexibility. Using a unique identification strategy, we document a significant cost. We find that actual repurchase investments underperform hypothetical investments that mechanically smooth repurchase dollars through time by approximately two percentage points per year on average. This cost of financial flexibility is correlated with earnings management, managerial entrenchment, and less institutional monitoring.

We critically reassess the notion that high liquid asset holding by firms faced with weak investor protection is evidence of managerial rent extraction. We show that firms facing agency problems may establish tight controls over management through concentrated ownership. Using data on Belgian listed firms between 1991 and 2006, we find a strong positive association between ownership concentration and cash holding. This indicates a precautionary motive on the part of the controlling shareholders who highly value control. We also find that firm market valuation is positively affected by the amount of cash held by firms. On the other hand, managerial ownership has no impact. These results are consistent with the hypothesis that firms' owners are pursuing a rational strategy to mitigate agency costs in the face of weak investor protections.

Effective consultation is critical for improving the audit of estimates. In an experiment where audit managers acted as consultants to other auditors, we examine conditions in which consultants either recommend estimates that differ substantially from advice-seekers’ assessments (contrariness) or recommend narrower reasonable ranges of estimates (precision). Psychology theory argues that both of these attributes can improve estimates. We examine whether these attributes depend on consultants' status motives, that is, the desire to gain respect from or power over others. We find that active status motives lead consultants with higher specialized knowledge to provide recommendations that are less contrary, but more precise. However, consultants increase precision by tightening range bounds in a manner that is not counter to management's preference and thus unlikely to prompt the audit team to challenge the estimate. We also find that higher consultant decision authority constrains precision. Our findings suggest limits to consultation's potential effectiveness in improving estimates. For instance, our findings suggest that firms and standard setters direct consultants to focus scrutiny on the range bound that is most likely to constrain management opportunism.

Long-run forecasts of economic variables play an important role in policy, planning, and portfolio decisions. We consider forecasts of the long-horizon average of a scalar variable, typically the growth rate of an economic variable. The main contribution is the construction of prediction sets with asymptotic coverage over a wide range of data generating processes, allowing for stochastically trending mean growth, slow mean reversion, and other types of long-run dependencies. We illustrate the method by computing prediction sets for 10- to 75-year average growth rates of U.S. real per capita GDP and consumption, productivity, price level, stock prices, and population.

In recent years, several states have initiated some form of economic instruction mandate in their high school curriculum. Although it may be argued that students more knowledgeable about economics should perform better as consumers and citizens, it is not clear that a state-imposed mandate will result in an optimal level of economic education. Accordingly, the purpose of this study is to investigate whether or not performance differences exist between students in a mandated and nonmandated environment.

This study examines the effects of managerial social capital on investment sensitivity to cash flow and Q. Using a large cross-country sample of companies for the period 1999–2012 and a traditional investment-Q framework, we discover that social capital reduces a firm's dependence on internally generated cash. We find that social capital is positively associated with investment sensitivity to Q. We further determine that social capital positively affects the sensitivity of external finance to Q, while inversely influencing the sensitivity of external finance to cash flow. These effects of social capital are stronger in markets characterized by the weak legal protection of investors. Our findings are robust to alternative model specifications, different variable measurements, and tests for endogeneity.