Exact linear rank tests for two‐sample equivalence problems with continuous data

The present paper introduces a methodology for the semiparametric or non‐parametric two‐sample equivalence problem when the effects are specified by statistical functionals. The mean relative risk functional of two populations is given by the average of the time‐dependent risk. This functional is a meaningful non‐parametric quantity, which is invariant under strictly monotone transformations of the data. In the case of proportional hazard models, the functional determines just the proportional hazard risk factor. It is shown that an equivalence test of the type of the two‐sample Savage rank test is appropriate for this functional. Under proportional hazards, this test can be carried out as an exact level α test. It also works quite well under other semiparametric models. Similar results are presented for a Wilcoxon rank‐sum test for equivalence based on the Mann–Whitney functional given by the relative treatment effect.     

The Effect of Employment while in High School on Educational Attainment: A Conditional Difference‐in‐Differences Approach*

Using American panel data from the National Education Longitudinal Study of 1988, this article investigates the effect of working during grade 12 on attainment. We employ, for the first time in the related literature, a semiparametric propensity score matching approach combined with difference‐in‐differences. We address selection on both observables and unobservables associated with part‐time work decisions, without the need for instrumental variable. Once such factors are controlled for, little to no effects on reading and math scores are found. Overall, our results therefore suggest a negligible academic cost from part‐time working by the end of high school.     

Option pricing in the moderate deviations regime

We consider call option prices close to expiry in diffusion models, in an asymptotic regime (“moderately out of the money”) that interpolates between the well‐studied cases of at‐the‐money and out‐of‐the‐money regimes. First and higher order small‐time moderate deviation estimates of call prices and implied volatilities are obtained. The expansions involve only simple expressions of the model parameters, and we show how to calculate them for generic local and stochastic volatility models. Some numerical computations for the Heston model illustrate the accuracy of our results.     

Zwischenbilanz: Krisengewinner und -verlierer

Die Finanz- und Wirtschaftskrise hat sich seit 2008 entfaltet. Seitdem gibt es verschiedene Versuche, ihre Folgen durch Rettungsschirme, Konjunkturprogramme und gesetzliche Regelungen in den Griff zu bekommen. Immer dringender stellt sich auch angesichts des jüngst vorgestellten Sparprogramms der Bundesregierung die Frage, wer tats?chlich von diesen Ma?nahmen profi tiert, wer sie bezahlen muss und ob die Verursacher der Krise angemessen an den Kosten der Schadensregulierung beteiligt werden.     

Social media adoption: A process-based approach

This research conceptualizes and measures social media adoption (SMA) of companies with a process-based approach and explains its antecedents of micro- and macro-environment, size, and ownership, as well as its consequence of intention to increase resources dedicated to social media. Based on data from 310 Turkish small and medium enterprises, the study first develops a conceptual framework on the pillars of internal and external stakeholder focus as well as relationship and information oriented implementation. Based on these two dimensions, it discusses the novel concepts of social customer relations, social stakeholder communication, social intelligence, and social responsiveness related to SMA. The study further indicates that ownership type and micro environment play a role in SMA and that path dependence exists in the interplay of current adoption and future intentions.     

Die Erwartungen der Wirtschaft für 2016

Last year saw only a moderate economic upturn, which will continue in 2016. Geopolitical risks and the loss of momentum in the emerging economies are obstacles that may hinder a positive trend in exports. However, the falling crude oil price and the low euro currency rate give hope for better prospects. On the domestic front, there is a strong focus on the digitisation of all sectors. Meanwhile, many problems result from the low level of investments and the high energy costs resulting from the energy transition. The insurance industry views the low-yield environment, which greatly intensified last year, as its main challenge in 2016.     

To buy or not to buy? The value of contradictory analyst signals

We study the predictive ability of individual analyst target price changes for post-event abnormal stock returns within each recommendation category. Although prior studies generally demonstrate the investment value of target prices, we find that target price changes do not cause abnormal returns within each recommendation level. Instead, contradictory analyst signals (e.g., strong buy reiterations with large target price decreases) neutralize each other, whereas confirmatory signals reinforce each other. Further, our analysis reveals that large target price downgrades can be explained by preceding stock price decreases. However, upgrades are not preceded by stock price increases, thereby demonstrating asymmetric analyst behavior when adjusting target prices to stock prices. Our results suggest that investors should treat recommendations with caution when they are issued with large contradictory target price changes. Thus, instead of blindly following a recommendation, investors might put more weight on the change in the corresponding target price and consider transaction costs.