Determinants of total efficiency in water utilities in Mexico

By using panel data analysis across 368 water utilities in Mexico over the period 2010–2014, we find that small firms are more efficient than medium and large providers and that increasing production is associated with less efficiency. Billing, income collection and profitability are relevant factors to improve efficiency. Medium and large firms require to measure consumption by service with meters in order to increase efficiency, while small firms do not require it.     

Federalism and Conflicts over Principalship. Some Insights into the American Constitutional History

The article provides an economic interpretation of Kelsen's theory of decentralized governments. It helps to distinguish different forms of federalism and in particular the corresponding conflicts of principalship inside the governmental structure. The model is applied to the early American constitutional history and shows how opposed views of agency relationships in the constitution foreshadowed what would later end up in a civil war.     

Option pricing under fast‐varying long‐memory stochastic volatility

Recent empirical studies suggest that the volatility of an underlying price process may have correlations that decay slowly under certain market conditions. In this paper, the volatility is modeled as a stationary process with long‐range correlation properties in order to capture such a situation, and we consider European option pricing. This means that the volatility process is neither a Markov process nor a martingale. However, by exploiting the fact that the price process is still a semimartingale and accordingly using the martingale method, we can obtain an analytical expression for the option price in the regime where the volatility process is fast mean reverting. The volatility process is modeled as a smooth and bounded function of a fractional Ornstein–Uhlenbeck process. We give the expression for the implied volatility, which has a fractional term structure.     

Inequality in Mortality: Updated Estimates for the United States,Canada and France*

This study provides comparisons of inequalities in mortality between the United States, Canada and France using the most recent available data. The period between 2010 and 2018 saw increases in mortality and in inequality in mortality for most age and gender groups in the United States. The main exceptions were children under 5 and adults over 65. In contrast, Canada saw a further flattening of mortality gradients in most groups, as well as further declines in overall mortality. The sole exception was Canadian women over 80 years old, who saw small increases in mortality rates. France saw continuing improvements in mortality rates in all groups. Both Canada and France have distributions of mortality that are much more equal than those in the United States, demonstrating the importance of public policy in the achievement of equality in health.     

ASSESSING THE REGIONAL ECONOMIC IMPACTS OF DEFENSE ACTIVITIES: A SURVEY OF METHODS

Defense activities exercised in a specific region may alter the region's economic performance. An accurate assessment of the potential economic impacts of defense activities is a valuable undertaking to enable regional planners to prepare for changes. The variety in the methods (among others, input–output models, economic base models, Keynesian regional multipliers, fixed‐effects estimators, and case‐study approaches) inspired by geography, sociology, and political science can pose a dilemma. We detail the historical and theoretical background of each method, as well as select exemplary cases where these methods were applied. By examining old and “new” methods, we aim to construct a typology that could be valuable to all stakeholders. In this sense, defense economics can also contribute to the allied social sciences by outlining evaluation methods that may be applicable to other fields.     

Option pricing under fast-varying and rough stochastic volatility

Recent empirical studies suggest that the volatilities associated with financial time series exhibit short-range correlations. This entails that the volatility process is very rough and its autocorrelation exhibits sharp decay at the origin. Another classic stylistic feature often assumed for the volatility is that it is mean reverting. In this paper it is shown that the price impact of a rapidly mean reverting rough volatility model coincides with that associated with fast mean reverting Markov stochastic volatility models. This reconciles the empirical observation of rough volatility paths with the good fit of the implied volatility surface to models of fast mean reverting Markov volatilities. Moreover, the result conforms with recent numerical results regarding rough stochastic volatility models. It extends the scope of models for which the asymptotic results of fast mean reverting Markov volatilities are valid. The paper concludes with a general discussion of fractional volatility asymptotics and their interrelation. The regimes discussed there include fast and slow volatility factors with strong or small volatility fluctuations and with the limits not commuting in general. The notion of a characteristic term structure exponent is introduced, this exponent governs the implied volatility term structure in the various asymptotic regimes.     

Vaccination under pessimistic expectations in clinical trials and immunization campaigns

We provide one of the first formalizations of a vaccination campaign in a decision-theoretic framework. We analyze a model where an ambiguity-averse individual must decide how much effort to invest into prevention in the context of a rampant disease. We study how ambiguity aversion affects the effort and the estimation of the vaccine efficacy in clinical trials and immunization campaigns. We find that the behaviors of individuals participating in a clinical trial differ from individuals not participating. Individuals who are more optimistic toward vaccination participate more in trials. Their behaviors and efforts are also affected. As a result, because vaccine efficacy depends on unobserved behaviors and efforts, the biological effect of the vaccine becomes difficult to evaluate. During the scale-up phase of a vaccination campaign, provided that vaccine efficacy is established, we show that vaccine hesitancy may still be rational.