Overconfidence in absolute and relative performance: The regression hypothesis and Bayesian updating

Studies have found that people are overconfident in estimation involving difficult tasks but underconfident in easy tasks. Conversely, they are overconfident in placing themselves in easy tasks but underconfident in hard tasks. These findings can be explained by a regression hypothesis that implies random errors in estimation as well as by rational Bayesian updating (that implies no random error). We test these hypotheses in five experiments. We find overconfidence in estimation involving hard tasks but underconfidence in easy tasks. However, for placement (involving both easy and hard tasks) we find no overconfidence, regression effects due to low and high anchor points, and extreme underconfidence when people choose between multiple alternatives. On the other hand, when given precise information about absolute performance, people’s re-assessments of relative performance are consistent with the Bayesian model. Since placement judgments are important in many competitive settings, our results emphasize the need for more research to identify their determinants.     

Lean-healthcare approach to reduce costs in a sterilization plant based on surgical tray rationalization

Abstract

Sterilization plants process all reusable materials used in hospitals during different stages of healthcare provision. Most items sterilized come from the surgical theater in the form of individual instruments, linen and surgical trays. Reducing the number of instruments in trays impacts on the performance of the sterilization process. Here, we propose a three-phase method, based on lean healthcare principles, cluster analysis and kaizen groups of experts to rationalize surgical trays, reducing sterilization processing costs. We innovate by proposing a strategy to approach tray rationalization prioritizing surgical specialties that are both complex and frequent, and by using group technology to cluster surgical trays expediting expert analyses carried out by kaizen groups. Our propositions were tested in a high complexity, tertiary care hospital, covering 12 surgical specialties, reducing the number of instruments by average 9.75%, and the time-to-assemble trays by average 9.68%, obtaining annual savings of US$285.756,00 in sterilization processing costs.     

Testing for additivity and joint effects in multivariate nonparametric regression using Fourier and wavelet methods

We consider the problem of testing for additivity and joint effects in multivariate nonparametric regression when the data are modelled as observations of an unknown response function observed on a d-dimensional (d 2) lattice and contaminated with additive Gaussian noise. We propose tests for additivity and joint effects, appropriate for both homogeneous and inhomogeneous response functions, using the particular structure of the data expanded in tensor product Fourier or wavelet bases studied recently by Amato and Antoniadis (2001) and Amato, Antoniadis and De Feis (2002). The corresponding tests are constructed by applying the adaptive Neyman truncation and wavelet thresholding procedures of Fan (1996), for testing a high-dimensional Gaussian mean, to the resulting empirical Fourier and wavelet coefficients. As a consequence, asymptotic normality of the proposed test statistics under the null hypothesis and lower bounds of the corresponding powers under a specific alternative are derived. We use several simulated examples to illustrate the performance of the proposed tests, and we make comparisons with other tests available in the literature.     

Mothers,fathers and children after divorce: The role of institutions

In recent years the increase in the divorce rate in many advanced countries and the predominance of female-headed families among the poor has generated much interest in the relationship between divorce and the welfare of mothers and children. In this paper I will review a small body of economic literature which has been recently developed in order to analyze the economic consequence of divorce on the welfare of fathers, mothers and children under alternative behavioral assumptions. Important economic and econometric issues arise from an analysis of welfare in non intact households as compared with intact households. In particular the focus is on the role that institutions play in post-divorce arrangements and important implications concerning policies for child support, custody, and visitation.Presidential Address of the Annual Congress of ESPE2000 held on June 15, 2000 in Bonn. I would like to thank Christopher Flinn, Rocio Ribero, Maristella Botticini and two anonymous referees for their helpful comments. Responsible editor: Alessandro Cigno.     

Testing appearance of linear trend

A test for the detection of a gradual change in simple linear regression is studied. Asymptotic distribution of the “maximum type” statistic is derived. Asymptotic critical values are compared with critical values obtained by simulations. The problem was motivated by the effort of meteorologists to discover a change in meteorological measurements.     

Applying multivariate techniques to high-dimensional temporally correlated fMRI data

In first-level analyses of functional magnetic resonance imaging data, adjustments for temporal correlation as a Satterthwaite approximation or a prewhitening method are usually implemented in the univariate model to keep the nominal test level. In doing so, the temporal correlation structure of the data is estimated, assuming an autoregressive process of order one.We show that this is applicable in multivariate approaches too - more precisely in the so-called stabilized multivariate test statistics. Furthermore, we propose a block-wise permutation method including a random shift that renders an approximation of the temporal correlation structure unnecessary but also approximately keeps the nominal test level in spite of the dependence of sample elements.Although the intentions are different, a comparison of the multivariate methods with the multiple ones shows that the global approach may achieve advantages if applied to suitable regions of interest. This is illustrated using an example from fMRI studies.     

CSR committees on boards: the impact of the external country level factors

Journal of Management and Governance - This article explores the spread of corporate social responsibility (CSR) committees in the European countries, examining whether and what country level...     

Analysis of the ergonomic usage of the ARMflex in the odontological area

The aim of this paper is to analyze the importance and applicability of ARMflex in the odontological area and its influence in preventing or stopping the involuntary habit of improperly positioning the hand under the face or under the pillow. The ergonomic usage of ARMflex influences the design in odontological areas and innovates in the semi-immobilization of the patient to prevent future orthodontic problems.     

A simple tool for preliminary hazard identification and quick assessment in craftwork and small/medium enterprises (SME)

During the last Congress of the International Ergonomics Association (IEA), Beijing, August 2009, an international group was founded aimed at developing a "toolkit for MSD prevention" within IEA and in collaboration with World Health Organization (WHO). Possible users of toolkits are: members of health and safety committees, health and safety representatives, line supervisors; labor inspectors; health workers implementing basic occupational health services; occupational health and safety specialists.According to ISO standard 11228 series and the new Draft CD ISO 12259-2009: Application document guides for the potential user, a computer software ( in Excel?) was create dealing with hazard "mapping" in handicraft The proposed methodology, using specific key enters and quick assessment criteria, allows a simple ergonomics hazard identification and risk estimation. Thus it makes possible to decide for which professional hazards a more exhaustive risk assessment will be necessary and which professional consultant should be involved (occupational physician, safety engineer, industrial hygienist, etc.).