A note on introducing a "zero‐line" of welfare as an escape route from Arrow's theorem

Since Sen's insightful analysis of Arrow's Impossibility Theorem, Arrow's theorem is often interpreted as a consequence of the exclusion of interpersonal information from Arrow's framework. Interpersonal comparability of either welfare levels or welfare units is known to be sufficient for circumventing Arrow's impossibility result. But it is less well known whether one of these types of comparability is also necessary or whether Arrow's conditions can already be satisfied in much narrower informational frameworks. This note explores such a framework: the assumption of (ONC + 0), ordinal measurability of welfare with the additional measurability of a "zero‐line", is shown to point towards new, albeit limited, escape routes from Arrow's theorem. Some existence and classification results are established, using the condition that social orderings be transitive as well as the condition that social orderings be quasi‐transitive.     

Ruin Problems for Phase-Type(2) Risk Processes

In this paper we consider a risk process in which claim inter-arrival times have a phase-type(2) distribution, a distribution with a density satisfying a second order linear differential equation. We consider some ruin related problems. In particular, we consider the compound geometric representation of the infinite time survival probability, as well as the (defective) distributions of the surplus immediately prior to ruin and of the deficit at ruin. We also consider explicit solutions for the infinite time ruin probability in the case where the individual claim amount distribution is phase-type.     

A Note on Forecasting Emerging Market Exchange Rates: Evidence of Anti‐herding

Using survey forecasts of a large number of Asian, European, and South American emerging market exchange rates, we studied empirically whether evidence of herding or anti‐herding behavior of exchange‐rate forecasters can be detected in the cross‐section of forecasts. Emerging market exchange‐rate forecasts are consistent with herding (anti‐herding) if forecasts are biased towards (away from) the consensus forecast. Our empirical findings provide strong evidence of anti‐herding of emerging market exchange‐rate forecasters.     

Der Flexibilitätsbeitrag in der Arbeitslosenversicherung

The controversy around fixed-term contracts centres around the conflict between the employer’s need for flexibility and the employee’s need for security. The authors propose flexible contributions for employers to the public unemployment insurance system to balance both interests. The employers’ contributions for their temporary staff would increase while the contributions for their permanent staff would in turn decrease slightly. The authors calculate four versions. With regards to the total sum of contributions, the first version holds the contributions received constant while the second version leads to a reduction. They then repeat these two calculations for fixed-term contracts without substantive grounds. The flexibility premium takes into account the higher unemployment risk of employees with fixed-term contracts and establishes monetary incentives for employers to hire employees with permanent contracts.     

CSR 2.0 — Die Kommunikation von Nachhaltigkeit in Sozialen Medien

Das Soziale Internet (Web 2.0) macht jeden potenziell zum Kommunikator — die Agenda-Setting-Funktion verlagert sich von den Massenmedien zu den Teilnehmern Sozialer Netze. Damit sehen sich Unternehmen einer zunehmend vielf?ltigen, selbstbewussten und kritischen ?ffentlichkeit gegenüber. Um Nachhaltigkeit glaubhaft zu kommunizieren, sollten Unternehmen sich daher als dialogbereiter Gespr?chspartner in Sozialen Netzen etablieren. Der vorliegende Beitrag leitet aus aktuellen Beispielen vier Spielregeln für die CSR-Kommunikation im Web 2.0 ab.     

Criteria for the Stochastic Ordering of Random Sums,with Actuarial Applications

It is shown that vectors ( S M 1 , … , S Mn ) and ( S' M'1 , …, S' M'n ) of random sums of positive random variables are stochastically ordered by upper orthant dependence, lower orthant dependence, concordance or by the supermodular ordering whenever their corresponding random numbers of terms ( M 1 , … , M n ) and ( M' 1 , … , M' n ) are themselves ordered in this fashion. Actuarial applications of these results are given to different dependence structures for the collective risk model with several classes of business.     

A nonparametric efficiency analysis of German public transport companies

In this paper, we present a nonparametric comparative efficiency analysis of 179 communal public transport bus companies in Germany (1990–2004). We apply both deterministic data envelopment analysis (DEA) and bootstrapping to test the robustness of our estimates and to test the hypothesis of global and individual constant returns to scale. We find that the average technical efficiency of German bus companies is relatively low. We observe that the industry appears to be characterized by increasing returns to scale for smaller companies. These results would imply increasing pressure on bus companies to restructure.     

The changing sensitivity of realized portfolio betas to U.S. output growth: An analysis based on real-time data

Our results shed light on the sensitivity of the betas of portfolios formed on market capitalization (“size”) and book-to-market value (“value”) to output growth in the United States. We estimate a state-space model to analyze the sensitivity of portfolio betas to output growth. We measure output growth using real-time and revised data. Output growth has a significant effect on portfolio betas when size and value are high. Such portfolio betas exhibit countercyclical dynamics. They are more sensitive, in absolute terms, to output growth when the latter is measured using real-time data. Their sensitivity to output growth has grown over time. Portfolio betas with respect to output growth have become smaller over time, in contrast, when size is large but value is low.