Business Cycle Volatility in Germany

Abstract. Stylized facts suggest that output volatility in OECD countries has declined in recent years. The causes and the nature of this decline have so far been analyzed mainly for the United States. In this paper, we analyze whether structural changes in output volatility in Germany can be detected. We report evidence that output volatility has declined in Germany. It is difficult to answer the question whether this decline in output volatility reflects good economic and monetary policy or merely ‘good luck’.     

Voluntary contributions to a public good when partial contribution is a dominant strategy

We present an experiment on voluntary contributions to a public good. The game has a dominant strategy solution in the interior of the strategy space. We observe significant over-contribution. Our result is similar to those of typical corner-solution experiments.     

Existence of Edgeworth equilibria for economies with asymmetric information

We analyze a general equilibrium model with asymmetrically informed agents. A basic and well-known consequence of asymmetric information is the failure of equal treatment property. Despite of this, we show that in every replica economy a private core allocation, which treats agents of the same type equally, exists. This result is provided in the framework of two different models, with and without expectations, and it suffices to guarantee in both cases the existence of a private Edgeworth equilibrium. The author is grateful to an anonymous referee for his/her careful reading and helpful comments and acknowledges support by Research Grant no. 2006132713-005 (Ministero Italiano dell’Università e della Ricerca).     

AID,POLICIES, AND GROWTH: WHY SO MUCH CONFUSION?

We revisit the highly debated aid‐policy‐growth association. Our results overturn Burnside and Dollar's original findings by simply using new data over the same countries and years. Marginal effects from the extended sample (1962–2013) provide weak evidence that aid can promote growth in the presence of good policies. Post‐Cold War (1990–2013) analysis, however, reveals that aid can decrease growth at any level of policy. The overwhelming majority of the results suggest aid conditional on policy is ineffective. This debate continues because the results are highly sensitive to country‐year selection, choice of methodology, measurement of institutional quality, and growth rate measurement. (JEL F35, O23, O40)     

Optimal portfolios when stock prices follow an exponential Lévy process

We investigate some portfolio problems that consist of maximizing expected terminal wealth under the constraint of an upper bound for the risk, where we measure risk by the variance, but also by the Capital-at-Risk (CaR). The solution of the mean-variance problem has the same structure for any price process which follows an exponential Lévy process. The CaR involves a quantile of the corresponding wealth process of the portfolio. We derive a weak limit law for its approximation by a simpler Lévy process, often the sum of a drift term, a Brownian motion and a compound Poisson process. Certain relations between a Lévy process and its stochastic exponential are investigated.Received: January 2003Mathematics Subject Classification: Primary: 60F05, 60G51, 60H30, 91B28; secondary: 60E07, 91B70JEL Classification: C22, G11, D81We would like to thank Jan Kallsen and Ralf Korn for discussions and valuable remarks on a previous version of our paper. The second author would like to thank the participants of the Conference on Lévy Processes at Aarhus University in January 2002 for stimulating remarks. In particular, a discussion with Jan Rosinski on gamma processes has provided more insight into the approximation of the variance gamma model.     

Math,girls and socialism

This paper argues that the socialist episode in East Germany, which constituted a radical experiment in gender equality in the labor market and other instances, has left persistent tracks on gender norms. We focus on one of the most resilient and pervasive gender gaps in modern societies: mathematics. Using the German division as a natural experiment, we show that the underperformance of girls in math is sharply reduced in the regions of the former GDR, in contrast with those of the former FRG. We show that this East–West difference is due to girls’ attitudes, confidence and competitiveness in math, and not to other confounding factors, such as the difference in economic conditions or teaching styles across the former political border. We also provide illustrative evidence that the gender gap in math is smaller in European countries that used to be part of the Soviet bloc, as opposed to the rest of Europe. The lesson is twofold: (1) a large part of the pervasive gender gap in math is due to social stereotypes; (2) institutions can durably modify these stereotypes.     

Improving Leadership Skills in Physicians: A 6‐Month Retrospective Study

The complex medical environment of today calls for physicians to have an array of leadership skills in addition to a thorough knowledge of their specific practice areas. The American College of Obstetrics and Gynecologists (ACOG) Robert C. Cefalo National Leadership Institute is a 3.5‐day intensive leadership development course targeted to physician leaders. A group of 37 physicians completed the ACOG National Leadership Institute in spring of 2013. At course completion and 6‐month postcourse, participants were asked to complete a retrospective pre‐ and posttest of perceived skill levels in 10 targeted competency areas. Course completion and 6‐month postcourse scores indicated statistically significant improvements in scores on all 10 competency areas, which was supported by a Wilcoxon signed‐rank test of median score difference. Qualitative data gathered at the 6‐month postcourse survey provide examples of how participants had applied their skills. The data presented in the current study suggested that intensive, “short‐burst,” experiential leadership training is an effective approach for leadership skills development in physicians.