Random perturbations of deterministic equilibria

This paper examines whether a small random deviation from a non-random policy process will destabilize the equilibrium exchange rate. The results focus on exchange rate dynamics when the government maintains a target zone or makes unanticipated deviations from a policy rule. With rational expectations small random shocks do not create large deviations from the policy rule exchange rate. If agents are approximately rational large deviations between exchange rates are possible.     

Wage bargaining and turnover costs with heterogenous labor and perfect history screening

We study effects of mobility costs in a model of (Nash) wage bargaining between workers and firms, with instantaneous matching, heterogeneous workers, identical firms and free firm entry, and where firms can screen workers perfectly according to their previous work history but not their actual productivity. We derive the employment level and the minimum worker quality standard, in the market solution, and in the efficient solution established by a social planner. When workers have positive bargaining power, there is always some inefficient unemployment among desired workers in the market solution. The lowest hiring standard chosen by firms is higher than the planner's standard when firing costs are high relative to hiring costs, but may be lower in the opposite case. We show that any higher established hiring standard corresponds to a market equilibrium. The model explains a tendency for a high initial unemployment rate to remain high, particularly for low-skilled workers.     

Corporate taxes, growth and welfare in a Schumpeterian economy

I take a new look at the long-run implications of taxation through the lens of modern Schumpeterian growth theory. I focus on the latest vintage of models that sterilize the scale effect through a process of product proliferation that fragments the aggregate market into submarkets whose size does not increase with the size of the workforce. I show that the following interventions raise welfare: (a) granting full expensibility of R&D to incorporated firms; (b) eliminating the corporate income tax and/or the capital gains tax; (c) reducing taxes on labor and/or consumption. What makes these results remarkable is that in all three cases the endogenous increase in the tax on dividends necessary to balance the budget has a positive effect on growth. A general implication of my analysis is that corporate taxation plays a special role in Schumpeterian economies and provides novel insights on how to design welfare-enhancing tax reforms.     

The behaviour of relative prices in the European Union: A sectoral analysis

Using multivariate unit root test methods, this paper investigates the Purchasing Power Parity (PPP) hypothesis at the sectoral level across six European countries over the last 17 years. Evidence of mean reversion towards PPP is found for the relative prices of some sectors and countries. Mean reversion in relative prices is explained by cross-country and cross-sectoral characteristics such as the distance between countries, nominal exchange rate volatility, differences in GDP per capita, non-tariff barriers, research and development, advertising, industrial concentration and tradeability of the products.     

Asset return dynamics and the FX risk premium in a decentralized dealer market

The paper proposes a continuous time model of an FX market organized as a multiple dealership. The dealers have costly access to best available quotes. They interpret signals from the joint dealer-customer order flow and decide upon their own quotes and trades in the inter-dealer market. Each dealer uses the observed order flow to improve the subjective estimates of relevant aggregate variables, which are the sources of uncertainty. The risk factors are returns on domestic and foreign assets and the size of the cross-border dealer transactions in the FX market. These uncertainties have diffusion form and are dealt with according to the principles of portfolio optimization in continuous time. The model is used to explain the country, or risk, premium in the uncovered national return parity equation for the exchange rate. The two country premium terms that I identify in excess of the usual covariance term (consequence of the “Jensen inequality effect”) are: the dealer heterogeneity-induced inter-dealer market order flow component and the dealer Bayesian learning component. As a result, an “order flow-adjusted total return parity” formula links the excess FX return to both the “fundamental” factors represented by the differential of the national asset returns, and the microstructural factors represented by heterogeneous dealer knowledge of the aggregate order flow and the fundamentals.     

Number needed to treat based on real-world evidence for non-vitamin K antagonist oral anticoagulants versus vitamin K antagonist oral anticoagulants in stroke prevention in patients with non-valvular atrial fibrillation

Aims: Non-vitamin K antagonist oral anticoagulants (NOACs) and vitamin K antagonists (VKAs) are used to prevent stroke in patients with atrial fibrillation (AF). This paper aimed to evaluate the clinical efficacy and safety of NOACs when compared to VKAs by calculating the number needed to treat (NNT) at 2 years using incidence rates and hazard ratios (HRs) derived from a meta-analysis of studies conducted in real-world settings.

Materials and methods: HRs were sourced from a published systematic literature review and a meta-analysis of real-world evidence on the use of NOACs vs VKAs. Rivaroxaban, dabigatran, and apixaban vs VKAs were investigated. The efficacy outcomes included: a composite of ischaemic stroke and systemic embolism (IS/SE), ischaemic stroke (IS), and all-cause mortality. The safety analysis assessed major bleeding and intracranial haemorrhage (ICH).

Results: Superiority of NOACs vs VKAs was observed in 10/15 comparisons. Treating patients with rivaroxaban and dabigatran was associated with a reduced risk of IS and all-cause mortality compared to VKAs, with one death prevented every 22 and 32 patients, respectively, and one IS prevented every 206 and 166 patients, respectively. Rivaroxaban was significantly associated with a reduced risk of IS/SE compared to VKA (NNT: 107). No significant differences were observed between apixaban and VKAs. Dabigatran and apixaban were associated with a reduced risk of major bleeding compared to VKA (NNT: 59 and 38, respectively). No significant difference was observed between rivaroxaban and VKAs regarding major bleeding. Rivaroxaban, dabigatran, and apixaban were significantly associated with a reduced risk of ICH (NNT: 205, 115, and 108, respectively).

Limitations: Heterogeneity in definitions of major bleeding across studies.

Conclusions: The NNT calculation, when approached and interpreted properly, is a practical measure of the effectiveness of a treatment. The calculation based on HRs showed that NOACs are safe and effective alternatives to VKAs in real life.     

Inflation forecast uncertainty

We study the inflation uncertainty reported by individual forecasters in the Survey of Professional Forecasters 1969-2001. Three popular measures of uncertainty built from survey data are analyzed in the context of models for forecasting and asset pricing, and improved estimation methods are suggested. Popular time series models are evaluated for their ability to reproduce survey measures of uncertainty. The results show that disagreement is a better proxy of inflation uncertainty than what previous literature has indicated, and that forecasters underestimate inflation uncertainty. We obtain similar results for output growth uncertainty.     

What causes violent crime?

This study uses panel data of intentional homicide and robbery rates for a sample of developed and developing countries for the period 1970-1994, based on information from the United Nations World Crime Surveys, to analyze the determinants of national crime rates both across countries and over time. A simple model of the incentives to commit crimes is proposed, which explicitly considers possible causes of the persistence of crime over time (criminal inertia). A panel-data based GMM methodology is used to estimate a dynamic model of national crime rates. This estimator controls for unobserved country-specific effects, the joint endogeneity of some of the explanatory variables, and the existence of some types of measurement errors afflicting the crime data. The results show that increases in income inequality raise crime rates, crime tends to be counter-cyclical, and criminal inertia is significant.     

Voluntary versus mandatory disclosure of liability insurance coverage limit

This article analyzes the disclosure of the liability insurance coverage limit and the impact of mandating disclosure of the coverage limit in a setting where voluntary disclosure of a firm’s cash flow information is subject to litigation risk and the firm has directors’ and officers’ (D&O) liability insurance. Disclosure of cash flow information is costly, but disclosure of the insurance coverage limit features no direct disclosure friction. We find that, when the litigation environment is weak, the usual unraveling argument applies, and the manager always voluntarily discloses the coverage limit in equilibrium. However, when the litigation environment is strong, either no coverage limit is disclosed or only sufficiently high coverage limits are disclosed in equilibrium. Further analysis shows that mandatory disclosure of the coverage limit increases the voluntary disclosure of cash flow information.     

On the efficient use of the informational content of estimating equations: Implied probabilities and Euclidean empirical likelihood

A number of information-theoretic alternatives to GMM have recently been proposed in the literature. For practical use and general interpretation, the main drawback of these alternatives, particularly in the case of conditional moment restrictions, is that they give up the computational and interpretational simplicity of quadratic optimization. The main contribution of this paper is to analyze the informational content of estimating equations within the unified framework of Chi-square distance. Improved inference by control variables, closed form formulae for implied probabilities and information-theoretic interpretations of continuously updated GMM are discussed in the two cases of unconditional and conditional moment restrictions.