Zur Messung von Forschungsqualit?t

This paper deals with the Forschungsrating (RWR) by the German Wissenschaftsrat (WR) in sociology. The WR??s objective in conducting this pilot study was to test a practice which allows a sophisticated assessment of the research facilities in Germany. Basically, two theses are exhibited towards the RWR in this paper: First, it seems possible that the published results are neither objective, nor reliable or valid because of implicit assessment procedures by the reviewers. Second we ask, whether a simple model of scientific quality, composed of a few quantitative indicators, yields similar results compared with the RWR. To empirically address these aspects, data of the RWR and our own standardized survey on the reputation of German research facilities is analyzed. Furthermore we conducted interviews with members of the group of reviewers. The results show that problems concerning the objectivity of analysis cannot be excluded. Our general conclusion about the reliability of the measurement, limited to the inner consistency of the quantitative indicators, is positive. A satisfactory reproduction of the RWR??s results solely based on quantitative data cannot be achieved. This is interpreted as a sign of minor validity. It is concluded that the amount and quality of data collected in the RWR, as well as the standardization of the rating process need to be improved.     

Wetland plant community variation across replicate urban to rural gradients: non-native species as both drivers and passengers in systems impacted by anthropogenic land-use

Urban Ecosystems - Anthropogenic land-use change impacts ecological communities in urban and rural landscapes, and wetlands are particularly vulnerable despite the valuable ecosystem services they...     

Motherhood and Earnings: Wage Variability by Major Occupational Category and Earnings Level

Prior research has indicated that women with children earn less than their childless counterparts. In addition, recent research has found that the motherhood wage penalty may be most severe for low-income earners. Using panel data from the National Longitudinal Survey of Youth (1979), we test two hypotheses. First, are there occupational differences in the motherhood wage penalty? Second, are there occupational differences in the relative wage penalty experienced by low and high wage mothers? Our results indicated that mothers in sales occupations are penalized at a significantly higher rate than mothers in non-sales occupations, while mothers in blue-collar occupations were penalized the least. Furthermore, the wage cost of motherhood was greatest amongst the highest earners in sales occupations.     

Abandon Statistical Significance

ABSTRACT

We discuss problems the null hypothesis significance testing (NHST) paradigm poses for replication and more broadly in the biomedical and social sciences as well as how these problems remain unresolved by proposals involving modified p-value thresholds, confidence intervals, and Bayes factors. We then discuss our own proposal, which is to abandon statistical significance. We recommend dropping the NHST paradigm—and the p-value thresholds intrinsic to it—as the default statistical paradigm for research, publication, and discovery in the biomedical and social sciences. Specifically, we propose that the p-value be demoted from its threshold screening role and instead, treated continuously, be considered along with currently subordinate factors (e.g., related prior evidence, plausibility of mechanism, study design and data quality, real world costs and benefits, novelty of finding, and other factors that vary by research domain) as just one among many pieces of evidence. We have no desire to “ban” p-values or other purely statistical measures. Rather, we believe that such measures should not be thresholded and that, thresholded or not, they should not take priority over the currently subordinate factors. We also argue that it seldom makes sense to calibrate evidence as a function of p-values or other purely statistical measures. We offer recommendations for how our proposal can be implemented in the scientific publication process as well as in statistical decision making more broadly.     

Are parents altruistic? Evidence from Mexico

Are parents altruistic or selfish? We contribute to the continuing debate of this question by proposing a simple test which is implemented using experimental data from the Mexican anti-poverty programme PROGRESA. Benefit eligibility is randomised. Our estimation strategy explicitly addresses potentially confounding factors and selection bias problems. We reject selfishness of parents in non-urban Mexico as PROGRESA beneficiaries spend more on child-related goods and do not increase spending on adult-related goods compared to parents in the control group. At the same time, we reject some rival theories.     

Statistical mining of interesting association rules

This article utilizes stochastic ideas for reasoning about association rule mining, and provides a formal statistical view of this discipline. A simple stochastic model is proposed, based on which support and confidence are reasonable estimates for certain probabilities of the model. Statistical properties of the corresponding estimators, like moments and confidence intervals, are derived, and items and itemsets are observed for correlations. After a brief review of measures of interest of association rules, with the main focus on interestingness measures motivated by statistical principles, two new measures are described. These measures, called α- and σ-precision, respectively, rely on statistical properties of the estimators discussed before. Experimental results demonstrate the effectivity of both measures.     

Coordination of supply chain investments and the advantage of revenue sharing

As examples of the practice show, revenue-sharing agreements between independent companies are arranged to coordinate a supply chain. Using an incomplete contracting model this article identifies conditions under which revenue-sharing agreements as well as pricing agreements are favorable for the involved companies. The main results show that revenue sharing increases the investment tendency of the upstream company to make revenue affecting specific investments and, under certain circumstances, increases the expected profit of both companies. Therefore, revenue sharing should be used if the success of the supply chain depends on a supply chain-crossing differentiation strategy.