How much does reducing inequality matter for global poverty?

The Journal of Economic Inequality - The goals of ending extreme poverty by 2030 and working towards a more equal distribution of incomes are part of the United Nations’ Sustainable...     

Complexity of determining the most vital elements for the p-median and p-center location problems

We consider the k most vital edges (nodes) and min edge (node) blocker versions of the p-median and p-center location problems. Given a weighted connected graph with distances on edges and weights on nodes, the k most vital edges (nodes) p-median (respectively p-center) problem consists of finding a subset of k edges (nodes) whose removal from the graph leads to an optimal solution for the p-median (respectively p-center) problem with the largest total weighted distance (respectively maximum weighted distance). The complementary problem, min edge (node) blocker p-median (respectively p-center), consists of removing a subset of edges (nodes) of minimum cardinality such that an optimal solution for the p-median (respectively p-center) problem has a total weighted distance (respectively a maximum weighted distance) at least as large as a specified threshold. We show that k most vital edges p-median and k most vital edges p-center are NP-hard to approximate within a factor $\frac{7}{5}-\epsilon$ and $\frac{4}{3}-\epsilon$ respectively, for any ?>0, while k most vital nodes p-median and k most vital nodes p-center are NP-hard to approximate within a factor $\frac{3}{2}-\epsilon$ , for any ?>0. We also show that the complementary versions of these four problems are NP-hard to approximate within a factor 1.36.     

Popularity kills the Talentstar? Einflussfaktoren auf Superstargeh?lter in der NBA

The observation that top athletes earn top salaries is well known. The (controversial) debate on superstar-salaries is mainly based on the two competing but equally plausible explanations outlined by Rosen (Am Eco Rev 71(5):845–858, 1981) and Adler (Am Eco Rev 75(1):208–212, 1985). Although both authors illustrate conclusive arguments, the discussion which of these two theories is more adequate in explaining superstar salaries still remains unsolved. The present paper analyzes salary information from the National Basketball Association (NBA) to explore the effect of Rosen’s (Am Eco Rev 71(5):845–858, 1981) talent approach versus the network and media approach by Adler (Am Eco Rev 75(1):208–212, 1985). Using innovative indicators for talent (draft position) and popularity (Facebook fans) in one model, the results of our preferred quantile regression specification indicates that player talent is stronger related to earning than popularity, particularly in the upper quantiles.     

Water pollution risk associated with natural gas extraction from the Marcellus Shale

In recent years, shale gas formations have become economically viable through the use of horizontal drilling and hydraulic fracturing. These techniques carry potential environmental risk due to their high water use and substantial risk for water pollution. Using probability bounds analysis, we assessed the likelihood of water contamination from natural gas extraction in the Marcellus Shale. Probability bounds analysis is well suited when data are sparse and parameters highly uncertain. The study model identified five pathways of water contamination: transportation spills, well casing leaks, leaks through fractured rock, drilling site discharge, and wastewater disposal. Probability boxes were generated for each pathway. The potential contamination risk and epistemic uncertainty associated with hydraulic fracturing wastewater disposal was several orders of magnitude larger than the other pathways. Even in a best-case scenario, it was very likely that an individual well would release at least 200 m3 of contaminated fluids. Because the total number of wells in the Marcellus Shale region could range into the tens of thousands, this substantial potential risk suggested that additional steps be taken to reduce the potential for contaminated fluid leaks. To reduce the considerable epistemic uncertainty, more data should be collected on the ability of industrial and municipal wastewater treatment facilities to remove contaminants from used hydraulic fracturing fluid.     

WHY AGNOSTIC SIGN RESTRICTIONS ARE NOT ENOUGH: UNDERSTANDING THE DYNAMICS OF OIL MARKET VAR MODELS

Sign restrictions on the responses generated by structural vector autoregressive models have been proposed as an alternative approach to the use of exclusion restrictions on the impact multiplier matrix. In recent years such models have been increasingly used to identify demand and supply shocks in the market for crude oil. We demonstrate that sign restrictions alone are insufficient to infer the responses of the real price of oil to such shocks. Moreover, the conventional assumption that all admissible models are equally likely is routinely violated in oil market models, calling into question the use of posterior median responses to characterize the responses to structural shocks. When combining sign restrictions with additional empirically plausible bounds on the magnitude of the short‐run oil supply elasticity and on the impact response of real activity, however, it is possible to reduce the set of admissible model solutions to a small number of qualitatively similar estimates. The resulting model estimates are broadly consistent with earlier results regarding the relative importance of demand and supply shocks for the real price of oil based on structural vector autoregressive (VAR) models identified by exclusion restrictions, but imply very different dynamics from the posterior median responses in VAR models based on sign restrictions only.     

Getting better or getting worse? Consumer responses to decreasing, constant, and ascending multi-dimensional price profiles

This research investigates consumer preferences for different multi-dimensional price profiles. Drawing on research on price affect, we investigate whether consumers prefer descending monthly installments (e.g., 40, 30, 20, 10) over constant (e.g., 25, 25, 25, 25), or ascending ones (e.g., 10, 20, 30, 40). Results of a field experiment with a sample of 1,628 German car buyers corroborate the hypothesized profile effect. In the experiment, participants were asked to evaluate different finance offers for a new car that all had the same present value but differed in terms of how the installments unfolded over time. Consistent with the hypotheses, decreasing monthly installments are evaluated more favorably than constant installments, which, in turn are evaluated more favorably than ascending installments. Furthermore, the results provide evidence for the underlying process by showing that the impact of different MDP profiles is mediated by positive affect. Finally, it was hypothesized that consumers’ individual differences (i.e., debt aversion, financial expectations, and product category knowledge) would exert a moderating influence on evaluations of different price profiles; these hypotheses, however, were only partially confirmed. Theoretical and managerial implications are discussed.     

Leadership across levels: Levels of leaders and their levels of impact

This article assesses 25 years of empirical leadership research in 11 top journals with the goal of understanding current practice and future needs for drawing solid conclusions about leadership at different hierarchical levels of the organization, as well as leadership’s effects on individuals, teams, units and organizations. We summarize the hierarchical level of leader and outcome level of analysis studied in different theoretical perspectives on leadership (traits, behavioral, transformational, LMX, strategic, shared) and by journal outlet. Among our findings, we observe that significantly less attention has been devoted to team- and unit-level emergent processes and outcomes, despite its conceptual relevance for leadership theory and practice. Four critical opportunities for advancing leadership science are presented.     

Cognitive,social, and neural determinants of diminished decision-making and financial exploitation risk in aging and dementia: A review and new model

ABSTRACT

In this article we will briefly review how changes in brain and in cognitive and social functioning, across the spectrum from normal to pathological aging, can lead to decision-making impairments that increase abuse risk in many life domains (e.g., health care, social engagement, financial management). The review will specifically focus on emerging research identifying neural, cognitive, and social markers of declining financial decision-making capacity in older adults. We will highlight how these findings are opening avenues for early detection and new interventions to reduce exploitation risk.     

Who Gives,Who Gets,and How do We Know? The Promises and Limitations of Administrative Data for Cross-border Philanthropy Tracking

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Cross-border philanthropy occurs across multiple dimensions simultaneously. Seemingly domestic actors become players in...