Importance sampling with the generalized exponential power density

In this paper, the generalized exponential power (GEP) density is proposed as an importance function in Monte Carlo simulations in the context of estimation of posterior moments of a location parameter. This density is divided in five classes according to its tail behaviour which may be exponential, polynomial or logarithmic. The notion of p-credence is also defined to characterize and to order the tails of a large class of symmetric densities by comparing their tails to those of the GEP density.The choice of the GEP density as an importance function allows us to obtain reliable and effective results when p-credences of the prior and the likelihood are defined, even if there are conflicting sources of information. Characterization of the posterior tails using p-credence can be done. Hence, it is possible to choose parameters of the GEP density in order to have an importance function with slightly heavier tails than the posterior. Simulation of observations from the GEP density is also addressed.     

Magic Transformation and Tragic Transformation—Splitting of Ego and Superego in Severely Traumatized Patients

Our fairy tales and myths, our dreams and fantasies, live from the wishes that we could magically change ourselves and the world we live in. In almost every hour of our psychotherapeutic or psychoanalytic work we meet this hope for magical transformation that our patients set in various objects in the outside: in drugs, or our presence, or in the symbiotic union with others, in money, in gambling, television, success, food and especially also in sexual gratification or religious ritual. Such magical transformation is contrasted by what George Eliot called tragic transformation. The term refers to a process of profound inner change brought about by suffering, i.e., trauma, through massive inner conflict, through insight and through action or active work, in behalf of somebody else, or in the service of a great cause. In the case described in detail, the magical transformation occurs with the establishment of several versions of double reality and double identity, as a way of dealing with extreme traumatization (killing of the mother by the father, the probable participation of the latter in the Holocaust, severe physical abuse). In the psychoanalysis, particular attention was being paid to conflicts within the superego. The gradual shift during therapy as a form of tragic transformation is being described.     

Is the SOGS an Accurate Measure of Pathological Gambling Among Children, Adolescents and Adults?

The South Oaks Gambling Screen (SOGS) is widely used to assess the prevalence of pathological gambling. For a variety of reasons, this instrument may not provide an accurate rate of the prevalence of pathological gambling. In this paper, one source of error in data provided by the SOGS is investigated. It is argued that individuals may not fully understand the meaning of some items, and that clarification of the meaning of misunderstood items may in some cases lead to a changed score on the scale. The present study evaluates respondents' understanding of the SOGS items. The results from three studies are reported, each using a different sample: grade school children, adolescents and adults. It was hypothesised that (1) participants would not understand some items of the SOGS, (2) problem gamblers and probable pathological gamblers would be more inclined to interpret items incorrectly than would non-problem gamblers and, (3) consistent with the first two hypotheses, clarification of items would decrease the number of participants identified as problem gamblers or probable pathological gamblers. The data obtained supported hypotheses 1 and 3. Furthermore, hypothesis 2 was supported for grade school children, but not for adolescents or adults. These results are consistent with recent literature on endorsement and acquiescence phenomena, and have implications for prevalence studies of probable pathological gambling.     

Replacement Cost Endorsement and Opportunistic Fraud in Automobile Insurance

Traditional insurance contracts do not offer protection against the replacement value of a vehicle. A replacement cost endorsement gives the opportunity to get a new vehicle in the case of a total theft or in the case of total destruction of the car in a road accident. This type of protection was introduced in Canada in the late 1980's. It is also offered in France and many insurers in the United States are going to move in that direction. We propose tests that separate moral hazard from adverse selection in the analysis of the effect of this additional protection on car theft. We show that holders of car insurance policies with a replacement cost endorsement have a higher probability of theft near the end of this additional protection (usually 24 months following the acquisition of a new car). Our tests indicate that this result is a form of ex post moral hazard or opportunistic insurance fraud.     

Methods for measuring school performance through cohort analysis

In order to evaluate the main educational characteristics of a grade cohort—which are the proportion of those who get a degree, the average time spent in school and finally the mean educational attainment of the cohort—we present a school system in which repeat enrolments are well identified. In this discrete model, we present, for each grade, three transition coefficients: the proportion of those passing to the next grade, the proportion of those repeating the grade and the proportion of those leaving the school system. Afterwards, we set up a system of equations leading to the distribution of the entrants in the cohort according to the levels of their educational attainment, a system of equations for which a simple solution will depend on two assumptions.     

Quantile Regression under Misspecification,with an Application to the U.S. Wage Structure

Quantile regression (QR) fits a linear model for conditional quantiles just as ordinary least squares (OLS) fits a linear model for conditional means. An attractive feature of OLS is that it gives the minimum mean‐squared error linear approximation to the conditional expectation function even when the linear model is misspecified. Empirical research using quantile regression with discrete covariates suggests that QR may have a similar property, but the exact nature of the linear approximation has remained elusive. In this paper, we show that QR minimizes a weighted mean‐squared error loss function for specification error. The weighting function is an average density of the dependent variable near the true conditional quantile. The weighted least squares interpretation of QR is used to derive an omitted variables bias formula and a partial quantile regression concept, similar to the relationship between partial regression and OLS. We also present asymptotic theory for the QR process under misspecification of the conditional quantile function. The approximation properties of QR are illustrated using wage data from the U.S. census. These results point to major changes in inequality from 1990 to 2000.     

The Effects of Environmental Regulations on the Productivity of Large Companies: An Empirical Analysis of the Spanish Case

This article provides evidence to the debateabout whether or not investments designated forcompliance with environmental performance andtechnology standards favor or harm the workproductivity of companies. A panel data modelis analyzed, which panel refers to 53 largeSpanish companies quoted on the stock exchangeand that have participated in a subsidizedenvironmental protection program during the1990–1995 period, specifically in theIndustrial and Technological Program for theEnvironment (PITMA). A Cobb-Douglas productionfunction is used to relate the workproductivity to a measure of the pollutionabatement investment dedicated to compliancewith standards. The resulting negativecoefficient, although close to zero, should notbe interpreted as a result derived from justany kind of regulation, but rather a result ofthe kind of regulation analyzed in this work,meaning the command and control regulation thatoften binds companies to make environmentalinvestments that are not productive in theconventional economic sense, although they areproductive in terms of environmental quality.In addition, and in order to specify the kindof company to which the conclusions of thispaper are applicable, the characteristics ofthe companies that participated in PITMA areanalyzed comparatively with companies that didnot participate.     

Ownership Structure,Corporate Value and Firm Investment: A Simultaneous Equations Analysis of Spanish Companies

This paper is concerned with the set of mutualrelationships between firm valuation andinvestment, and with the possible endogeneityof ownership structure. In order to deal withthem properly, we aim to test the mutual impactof investment, corporate value and ownership bybroadening the usual framework with asimultaneous equations approach. Using a sampleof 140 Spanish listed companies for the1991–1997 period, we have found that,consistent with previous research, thealignment and entrenchment hypotheses seem tobe confirmed by the estimation of aone-equation model. However, when analyzed bymeans of a system of simultaneous equations inwhich a set of mutual relationships isintroduced, quite different results wereobtained. Although valuation and investment offirms are determined by managerial ownership,we have found that ownership structure may alsobe influenced both by investment and value.Consequently, it is not completely right toinfer that ownership structure determines firmvalue unidirectionally; however the benchmarkshould be broadened so as to take an explicitaccount of the mutual links between firm value,investment and ownership.     

Organizational Alternatives for Companies' Management of Occupational Risks: The Examples of Spain and Argentina

This study discusses the various options available to companies for the management of occupational risks. In this context, occupational accident insurance schemes in Spain and Argentina are analysed, with reference to the theory of organizational economics. Spain has 75 years' experience of such schemes, while in Argentina they have only recently been introduced. Although the two models have similar goals, their differences, in terms of competition, regulation and ownership, lead to different incentives for those concerned: workers, companies, insurers and regulatory bodies.