Robust estimation methods for exponential data: a monte-carlo comparison

We compare the performance of seven robust estimators for the parameter of an exponential distribution. These include the debiased median and two optimally-weighted one-sided trimmed means. We also introduce four new estimators: the Transform, Bayes, Scaled and Bicube estimators. We make the Monte Carlo comparisons for three sample sizes and six situations. We evaluate the comparisons in terms of a new performance measure, Mean Absolute Differential Error (MADE), and a premium/protection interpretation of MADE. We organize the comparisons to enhance statistical power by making maximal use of common random deviates. The Transform estimator provides the best performance as judged by MADE. The singly-trimmed mean and Transform method define the efficient frontier of premium/protection.     

Price Manipulation and Quasi‐Arbitrage

In an environment where trading volume affects security prices and where prices are uncertain when trades are submitted, quasi‐arbitrage is the availability of a series of trades that generate infinite expected profits with an infinite Sharpe ratio. We show that when the price impact of trades is permanent and time‐independent, only linear price‐impact functions rule out quasi‐arbitrage and thus support viable market prices. When trades have also a temporary price impact, only the permanent price impact must be linear while the temporary one can be of a more general form. We also extend the analysis to a time‐dependent framework.     

Preliminary Evaluation of the Validity and Reliability of the Spanish Version of the Therapeutic Alliance with Clinician (TAC) Questionnaire

As part of a broader study aimed at evaluating perceived alliance with service providers and level of satisfaction with services received, 103 monolingual Spanish speaking Hispanic women were interviewed. Participants were receiving ongoing behavioral health treatment at three different community service provider sites located in the greater New Haven area in Connecticut. These sites included a community health center (n = 40), a community behavioral health center (n = 40), and a faith-based agency (n = 23). As part of this study, the English version of the Therapeutic Alliance with Clinician (TAC) questionnaire was translated into Spanish and administered to our sample of Hispanic women. Results on the psychometric properties of the Spanish version of the TAC are presented in this article.     

ARE THE DISABLED LESS LOSS AVERSE? EVIDENCE FROM A NATURAL POLICY EXPERIMENT

Research findings show that disabled persons often develop physical and psychological mechanisms to compensate for disabilities. Coping mechanisms may not be limited to the psychophysiological domain and may extend to cognitive bias and loss aversion. In this study, we apply unique microdata from a natural policy experiment to assess the role of loss aversion in home purchase among nondisabled and disabled households. Results of survival analysis indicate that the physically disabled are substantially less loss averse in home purchase. Furthermore, loss aversion varies with other population characteristics and attenuates with degree of disability. Findings provide new evidence of diminished cognitive bias and more rational economic decision‐making among the physically disabled. (JEL D03, C9, R38)     

Disentangling combinations and contingencies of generic strategies: A set-theoretic configurational approach

Porter's framework of generic strategies conceptualizes key elements of firms' strategic positions in their industry. Research on these generic strategies has been challenged by the complexity of capturing relations between generic strategies (i.e., cost leadership, differentiation, and focus) and their interdependencies with other strategic commitments for performance outcomes. We address these challenges by utilizing fuzzy set Qualitative Comparative Analysis (fsQCA) to explore the causal complexity underlying the links between generic strategies and firm performance. Specifically, we study combinations of firms' generic strategies and other strategy attributes as paths to high or low performance in the U.S. and Canadian airline industry. We find six equifinal configurations that are consistently linked to high performance and nine configurations that are consistently linked to the absence of high performance. Our findings shed light on the contingencies underlying performance consequences of generic strategies. Consequently they redirect theoretical debates on the links between generic strategies and firm performance as well as on the superiority of pure versus hybrid generic strategies towards relations of set-theoretic of necessity and sufficiency. Specifically, we show that having a generic strategy advantage is not sufficient for high performance but that it is a vital ingredient in recipes for success. Similarly, our findings suggest that a generic strategy disadvantage is not sufficient for low performance, but is a key ingredient in all paths to poor performance. We conclude with a discussion of our study's contributions to the literature, suggestions for future research, and implications for managerial practice.     

The Medium Is the Danger: Discourse about Television among Amish and Ultra-Orthodox (Haredi) Women

This study shows how Old Order Amish and ultra-Orthodox women’s discourse about television can help develop a better understanding of the creation, construction, and strengthening of limits and boundaries separating enclave cultures from the world. Based on questionnaires containing both closed- and open-ended questions completed by 82 participants, approximately half from each community, I argue that both communities can be understood as interpretive communities that negatively interpret not only television content, like other religious communities, but also the medium itself. Their various negative interpretive strategies is discussed and the article shows how they are part of an “us-versus-them” attitude created to mark the boundaries and walls that enclave cultures build around themselves. The comparison between the two communities found only a few small differences but one marked similarity: The communities perceive avoidance of a tool for communication, in this case television, as part of the communities’ sharing, participation, and common culture.     

Exact Bootstrap Variances of the Area Under ROC Curve

The area under the Receiver Operating Characteristic (ROC) curve (AUC) and related summary indices are widely used for assessment of accuracy of an individual and comparison of performances of several diagnostic systems in many areas including studies of human perception, decision making, and the regulatory approval process for new diagnostic technologies. Many investigators have suggested implementing the bootstrap approach to estimate variability of AUC-based indices. Corresponding bootstrap quantities are typically estimated by sampling a bootstrap distribution. Such a process, frequently termed Monte Carlo bootstrap, is often computationally burdensome and imposes an additional sampling error on the resulting estimates. In this article, we demonstrate that the exact or ideal (sampling error free) bootstrap variances of the nonparametric estimator of AUC can be computed directly, i.e., avoiding resampling of the original data, and we develop easy-to-use formulas to compute them. We derive the formulas for the variances of the AUC corresponding to a single given or random reader, and to the average over several given or randomly selected readers. The derived formulas provide an algorithm for computing the ideal bootstrap variances exactly and hence improve many bootstrap methods proposed earlier for analyzing AUCs by eliminating the sampling error and sometimes burdensome computations associated with a Monte Carlo (MC) approximation. In addition, the availability of closed-form solutions provides the potential for an analytical assessment of the properties of bootstrap variance estimators. Applications of the proposed method are shown on two experimentally ascertained datasets that illustrate settings commonly encountered in diagnostic imaging. In the context of the two examples we also demonstrate the magnitude of the effect of the sampling error of the MC estimators on the resulting inferences.     

Creating places,relationships and education for refugee children in camps: Lessons learnt from the ‘The School of Peace’ educational model

This paper describes a unique model for building an afternoon school for refugee children sustained by volunteers and refugee teachers and based on humanistic intercultural values. The methodology is participatory including the whole school, from children to teachers to volunteers and managers. Central themes in the findings include a synergetic focus on creative placemaking, conflict negotiation and formal studies. This points to a theoretical connection between informal and formal studies. The findings teach us about the needs of refugee children. A methodological contribution is the use of arts-based methods to capture refugee children's lived experiences of school.     

Controlling for Response Biases Clarifies Sex and Age Differences in Facial Affect Recognition

Sex, age and education differences in facial affect recognition were assessed within a large sample (n = 7,320). Results indicate superior performance by females and younger individuals in the correct identification of facial emotion, with the largest advantage for low intensity expressions. Though there were no demographic differences for identification accuracy on neutral faces, controlling for response biases by males and older individuals to label faces as neutral revealed sex and age differences for these items as well. This finding suggests that inferior facial affect recognition performance by males and older individuals may be driven primarily by instances in which they fail to detect the presence of emotion in facial expressions. Older individuals also demonstrated a greater tendency to label faces with negative emotion choices, while females exhibited a response bias for sad and fear. These response biases have implications for understanding demographic differences in facial affect recognition.     

Arguing for a Generous Identity

A generous person is one who freely gives assistance to others. In this article, we provide evidence in support of the existence of a generous identity. To do this, we first outline ways in which generosity relates to other constructs such as altruism, helping behavior, volunteerism, and philanthropy and offer explanations as to why it is important to study generous identity both alone and in tandem with these related constructs. Next, we briefly discuss how generosity can be conceptualized as a person identity. We then recommend best practices for developing and implementing a measure for generous identity. Lastly, we discuss the implications of a generous identity and ways in which its salience can play a role in different contexts.