The cost of not knowing the radius

Robust Statistics considers the quality of statistical decisions in the presence of deviations from the ideal model, where deviations are modelled by neighborhoods of a certain size about the ideal model. We introduce a new concept of optimality (radius-minimaxity) if this size or radius is not precisely known: for this notion, we determine the increase of the maximum risk over the minimax risk in the case that the optimally robust estimator for the false neighborhood radius is used. The maximum increase of the relative risk is minimized in the case that the radius is known only to belong to some interval [r _l ,r _u ]. We pursue this minmax approach for a number of ideal models and a variety of neighborhoods. Also, the effect of increasing parameter dimension is studied for these models. The minimax increase of relative risk in case the radius is completely unknown, compared with that of the most robust procedure, is 18.1% versus 57.1% and 50.5% versus 172.1% for one-dimensional location and scale, respectively, and less than 1/3 in other typical contamination models. In most models considered so far, the radius needs to be specified only up to a factor , in order to keep the increase of relative risk below 12.5%, provided that the radius–minimax robust estimator is employed. The least favorable radii leading to the radius–minimax estimators turn out small: 5–6% contamination, at sample size 100.      

In search of excellence: a case study of the first excellence initiative of Germany

As higher education policies are often associated with intense public spending, the evaluation and performance measurement of respective initiatives becomes increasingly crucial. An extensive and fruitful strand of literature has dealt with the assessment of university performance, yet mainly focused on point-in-time rather than period-of-time examinations. This study investigates the effects of Germany’s first Excellence Initiative, a political measure aimed at building up world-class universities to be able to compete in the globalizing research world. Relying on both qualitative and quantitative measures, taking into account a 15-year period from 1998 to 2012, we analyze the selection process and how and whether the Excellence Initiative fulfilled its ambitious goals. Our results suggest that not the political initiative per se, i.e. the treatment, but the announcement of the treatment triggered diverging performance paths within the German higher education system, thus positively contributed to augmented research performance of the promoted universities. Based on these findings, we provide policy recommendations and avenues for future research.     

Research evaluation and journal quality weights

Research evaluations based on quality weighted publication output are often criticized on account of the employed journal quality weights. This study shows that evaluations of entire research organizations are very robust with respect to the choice of readily available weighting schemes. We document this robustness by applying rather different weighting schemes to otherwise identical rankings. Our unit of analysis consists of German, Austrian and Swiss university departments in business administration and economics.     

Knowledge Management in Strategic Alliances: A Review of Empirical Evidence

Knowledge‐related and organizational learning processes in alliances have received much attention throughout the last 25 years. The field has generated a rapidly growing body of empirical evidence on how knowledge is managed in alliances. However, the sphere is highly complex, fragmented, incoherent, and heterogeneous in terms of the theoretical approaches applied. This paper presents an integrative and organizing framework for the empirical literature on knowledge management in strategic alliances. It illustrates how the knowledge management outcomes of knowledge creation, transfer and application are determined by four distinct sets of factors: knowledge characteristics, partner characteristics, partner interaction, and active knowledge management. Based on this framework, this review analyses and integrates empirical evidence in order to identify where findings converge and where results conflict. So far, research has focused strongly on singular interrelations between these four sets of factors and the transfer of knowledge. Conversely, the questions of how knowledge is created, retained, retrieved and applied and how the interplay of the different factors affects knowledge management in strategic alliances remain widely unexplored. The review concludes with a summary of the current state of the art in empirical research and discusses some promising avenues for future investigation.     

Vertrauen bei Internet-Auktionen

The text replies to the article “Trust and Reputation in Internet-Auctions” (KZfSS, Vol. 54, No. 4, pp. 674–693) by Diekmann and Wyder. In principle the authors’ consideration regarding a premium for reputation for trustworthy participants in internet auctions seems to be attractive. However, we object to the lacking definitions of the categories of trust and reputation as well as to the problematic design of their central indicator (reputation). With regard to their interpretation we criticize the missing consideration of qualitative — especially negative — statements in the public rating systems, underestimating the relevance of “critical incidents” to fragile trust relations on the internet. Finally we remark that Diekmann and Wyder misjudge the founding, cultivating and modifying activities (including imposing sanctions) of the platform owner towards this institution regulating the market.     

A 1,408 km bicycle tour with prostate cancer patients—results of a pilot study

Negative psychological and physical effects of prostate cancer and its medical treatment may persist many years after diagnosis. The influence of a long cycling tour on rehabilitative or health-related effects with prostate cancer patients has not yet been studied. In practice, physicians and therapists rarely recommend cycling to prostate cancer. In May 2010, eight prostate cancer patients rode their bikes for over 1,408 km from Cologne to Marseille within 5 weeks. Endurance test, blood examinations (prostate-specific antigen (PSA), total testosterone, interleukin-6, oxidative stress, and antioxidant capacity) and quality of life questionnaires were completed before and after the tour. All eight subjects reached Marseille. Significant improvements could be observed in physical performance and certain quality of life scores (p?=?0.008), as well as a reduction of total testosterone (p?=?0.19). PSA levels did not change. This pilot study suggests that long bicycle tours with prostate cancer patients are feasible. Due to the missing control group and the small sample size, the results of this pilot study are limited.