A new estimate of skewness with mean-squared error smaller than that of the sample skewness

Recently, a new procedure for distribution fitting, based on matching of the first two moments, partial and complete, was introduced (Shore, 1995). When the sampling skewness of the fitted distribution is compared to the sample skewness, and both are regarded as estimates of the skewness of the underlying distribution, the mean-squared-error of the former is appreciably lower than that of the latter. In this paper we present some simulation results to support this claim and demonstrate its magnitude. An alternative two-moment distributional fitting procedure, based on a new family of four-parameter distributions, is also introduced and studied. Since three-moment distribution fitting is very common practice in simulation studies, these results may have important implications for the current state-of-the-art of simulation     

‘It is hard at school,but I do my best to cope.’: the educational experience of multilingual immigrant youth in high school

ABSTRACT

This study explored how 60 trilingual immigrant youth interpret and make sense of their educational experiences in Israeli schools. Conceptualizing the language knowledge of multilingual individuals as one unitary system, the study is based on the assumption that a fuller understanding of students’ educational experiences can be obtained by examining their written expression about school experiences in the three languages at their disposal: Russian (L1), Hebrew (L2) and English (L3), which were elicited via letter writing tasks. A total of 180 letters (60 letters in each language) were analysed through qualitative content analyses revealing five interrelated themes depicting immigrant youths’ scholastic studies as a complex multifaceted experience intertwined with issues of language, culture, identity, and social struggles. The findings provide insights into how the language repertoire of immigrant youth is powerfully linked to their sense of self, educational circumstances, and acculturation.     

Adaptation and Evaluation of a Nonviolent Resistance Intervention for Foster Parents: A Progress Report

Foster care faces serious challenges, such as behavioral problems in foster children and parental stress and ineffective parenting behavior in foster parents. The results of a pilot study that evaluated a training program for foster parents based on nonviolent resistance are described. In a pretest–posttest design, data were collected from 25 families. Significant reductions in externalizing, internalizing, and total problem behavior in the foster children and in parenting stress were found. Using a reliable change index, significant improvements in externalizing, internalizing, and total problem behavior were found in, respectively, 72, 44, and 80% of the cases. Most improvements proved to be clinically relevant. Effect sizes ranged from medium to large for problem behavior, and from small to medium for parenting stress.     

NEW PRODUCT SCREENING VIA THE INTENTION-TO-BUY SCALE*

Data obtained from the intention-to-buy scale often are used for early product screening. The authors discuss current procedures to evaluate these data and indicate the minor rote that risk assessment has played. Evaluation rules that incorporate the risk factor are presented, and their usefulness for product selection is discussed.     

What social workers talk about when they talk about child care proceedings in the District Court in Ireland

Court proceedings are a fundamental and increasingly time‐consuming aspect of social work practice. However, to date, there is a relatively modest body of literature considering the experiences of social workers in instituting child care proceedings and giving evidence in court. This paper draws on data gathered as part of an in‐depth qualitative study of professional experiences of District Court child care proceedings in Ireland and presents findings regarding the experiences of social workers in bringing court applications for child protection orders. It seeks to answer 2 key questions: First, how do child protection and welfare social workers experience the adversarial nature of child care proceedings in the District Court? Second, what are the views of child protection and welfare social workers on the strengths and weaknesses of child care proceedings as a decision‐making model for children and young people? The main findings are that social workers expressed significant reservations about the predominantly adversarial model that currently operates in Irish child care proceedings and about the level of respect that social workers are afforded within the operation of the system.     

Comparison of Generalized Lambda Distribution (GLD) and Response Modeling Methodology (RMM) as General Platforms for Distribution Fitting

Distribution fitting is widely practiced in all branches of engineering and applied science, yet only a few studies have examined the relative capability of various parameter-rich families of distributions to represent a wide spectrum of diversely shaped distributions. In this article, two such families of distributions, Generalized Lambda Distribution (GLD) and Response Modeling Methodology (RMM), are compared. For a sample of some commonly used distributions, each family is fitted to each distribution, using two methods: fitting by minimization of the L ₂ norm (minimizing density function distance) and nonlinear regression applied to a sample of exact quantile values (minimizing quantile function distance). The resultant goodness-of-fit is assessed by four criteria: the optimized value of the L ₂ norm, and three additional criteria, relating to quantile function matching. Results show that RMM is uniformly better than GLD. An additional study includes Shore's quantile function (QF) and again RMM is the best performer, followed by Shore's QF and then GLD.     

Stochastic Dominance and Prospect Dominance with Subjective Weighting Functions

Laboratory experiments with and without real money repeatedly reveal that even if all subjects observe the same pair of cumulative distributions F and G, they act as if they were other cumulative probability functions F* and G* different for different investors. Namely, the subjects assign (subjective) weights to the various probabilities. In their breakthrough article Kahneman and Tversky [1979] suggest that in making decisions under uncertainty, the subjects apply a monotonic transformation (p) where p are the probabilities, and investors make decisions by comparing (p) corresponding to the two distributions under consideration rather than by comparing the true probabilities, p, themselves.     

Divide and Conquer: Competing with Free Technology Under Network Effects

We study how a commercial firm competes with a free open source product. The market consists of two customer segments with different preferences and is characterized by positive network effects. The commercial firm makes product and pricing decisions to maximize its profit. The open source developers make product decisions to maximize the weighted sum of the segments' consumer surplus, in addition to their intrinsic motivation. The more importance open source developers attach to consumer surplus, the more effort they put into developing software features. Even if consumers do not end up adopting the open source product, it can act as a credible threat to the commercial firm, forcing the firm to lower its prices. If the open source developers' intrinsic motivation is high enough, they will develop software regardless of eventual market dynamics. If the open source product is available first, all participants are better off when the commercial and open source products are compatible. However, if the commercial firm can enter the market first, it can increase its profits and gain market share by being incompatible with its open source competitor, even if customers can later switch at zero cost. This first‐mover advantage does not arise because users are “locked in,” but because the commercial firm deploys a “divide and conquer” strategy to attract early adopters and exploit late adopters. To capitalize on its first‐mover advantage, the commercial firm must increase its development investment to improve its product features.     

Arrow-Pratt Risk Aversion, Risk Premium and Decision Weights

This paper analyzes two issues: (a) the effect of decision-weights on risk premium, and (b) whether risk-aversion characterizes most investors. We theoretically show that cumulative prospect theory decision-weights systematically increase Arrow's risk premium, and may induce a positive risk premium even in the absence of risk-aversion. However, decision-weights may either increase or reduce Pratt's risk premium. We present three experiments revealing a striking result: a large proportion of the subjects' choices contradicts risk-aversion. This may be due to non-concave preferences, or to decision-weights. This result may have a dramatic impact on equilibrium models in economics and finance.