Le vol en interne : les vols commis par les salariés sur leur lieu de travail

The literature in the social sciences about theft by employees at the workplace is reviewed. As field studies and surveys based on personal accounts show, this deviant behavior is widespread in the world of work. Sociologists and anthropologists mostly interpret employee theft as a political way of resisting the injustice of on-the-job exploitation. In contrast, economists and the literature on management insist on the delinquency of theft and try to find the means whereby employers can preventively cope with dishonest salary-earners. Beyond this distinction, employee theft is worth studying in order to shed light on the complex salary-earning relationship.     

Unbiased and almost unbiased ratio estimators of the population mean in ranked set sampling

In this paper we study the problem of reducing the bias of the ratio estimator of the population mean in a ranked set sampling (RSS) design. We first propose a jackknifed RSS-ratio estimator and then introduce a class of almost unbiased RSS-ratio estimators of the population mean. We also present an unbiased RSS-ratio estimator of the mean using the idea of Hartley and Ross (Nature 174:270?C271, 1954) which performs better than its counterpart with simple random sample data. We show that under certain conditions the proposed unbiased and almost unbiased RSS-ratio estimators perform better than the commonly used (biased) RSS-ratio estimator in estimating the population mean in terms of the mean square error. The theoretical results are augmented by a simulation study using a wheat yield data set from the Iranian Ministry of Agriculture to demonstrate the practical benefits of our proposed ratio-type estimators relative to the RSS-ratio estimator in reducing the bias in estimating the average wheat production.     

Organizational Stages and Cultural Phases: A Critical Review and a Consolidative Model of Corporate Social Responsibility Development

Based on a stakeholder-oriented conceptualization of corporate social responsibility (CSR), this paper offers a multi-dimensional, dynamic perspective which integrates moral, cultural and strategic aspects of the CSR development process, together with its organizational implications. Therefore, the authors link existing stage models of CSR development with stakeholder culture and social responsiveness continuums and provide a consolidative model which highlights a seven-stage development process towards CSR, articulated around three cultural phases (i.e. CSR reluctance, CSR grasp and CSR embedment). In a context in which literature on CSR development and implementation tends to be overly segmented, this consolidative model integrates organizational values and culture together with management processes and operations. In its emphasis on the importance of the organizational context and characteristics in analyses of organizations' CSR development, the proposed consolidative model offers novel research perspectives and highlights the relevance of adopting a phase-dependent approach.     

Nested Kriging predictions for datasets with a large number of observations

This work falls within the context of predicting the value of a real function at some input locations given a limited number of observations of this function. The Kriging interpolation technique (or Gaussian process regression) is often considered to tackle such a problem, but the method suffers from its computational burden when the number of observation points is large. We introduce in this article nested Kriging predictors which are constructed by aggregating sub-models based on subsets of observation points. This approach is proven to have better theoretical properties than other aggregation methods that can be found in the literature. Contrarily to some other methods it can be shown that the proposed aggregation method is consistent. Finally, the practical interest of the proposed method is illustrated on simulated datasets and on an industrial test case with \(10^4\) observations in a 6-dimensional space.     

Combining ROC curves using MAMSE weighted distributions

The receiver operating characteristic (ROC) curve can be used to evaluate the properties of a diagnostic test from the distribution of a variable on the healthy and diseased populations. The minimum averaged mean squared error (MAMSE) weights were developed to handle data from different sources by adjusting the relative contribution of each data source. The authors use the MAMSE weights to infer the ROC curve of a diagnostic test based on raw data from multiple studies. The proposed estimates are consistent and Monte Carlo simulations show favourable finite sample performance. The method is illustrated in a case study where progesterone level is used to detect ectopic pregnancies and abortions from other natural causes. The Canadian Journal of Statistics 46: 298–315; 2018 © 2018 Statistical Society of Canada     

Building strategy on technological resources and commercial proactiveness: The Gemplus case

This article uses the resource-based framework for analyzing the strategy of Gemplus, a spin-off of the French group Thomson, that has grown by 50 per cent each year since its creation in 1988. Three points are highlighted: (1) Gemplus combined various resources in order to build a distinctive competence base in three areas: smart cards design, mass production and mass customization, commercial capabilities. (2) The company's strategy is two-fold: a constant enlargement of the spectrum of applications of its core product (i.e. the smart card), supported by technology exploitation and commercial awareness, and an aggressive search for new geographical markets, supported by commercial proactiveness. (3) Gemplus continuously nurtures its resource base through a vast network of partners (with means such as R&D and joint-ventures). To summarize, we explain the success of Gemplus by a talented balance between an outside-in and an inside-out approach.     

Robust Inference in Two‐phase Sampling Designs with Application to Unit Nonresponse

Influential units occur frequently in surveys, especially in business surveys that collect economic variables whose distributions are highly skewed. A unit is said to be influential when its inclusion or exclusion from the sample has an important impact on the sampling error of estimates. We extend the concept of conditional bias attached to a unit and propose a robust version of the double expansion estimator, which depends on a tuning constant. We determine the tuning constant that minimizes the maximum estimated conditional bias. Our results can be naturally extended to the case of unit nonresponse, the set of respondents often being viewed as a second‐phase sample. A robust version of calibration estimators, based on auxiliary information available at both phases, is also constructed.     

Monthly Instability in Early Adolescent Friendship Networks and Depressive Symptoms

This study examined (1) the relation between perceived friendship instability and depressive symptoms, (2) the directionality of this link, and (3) whether the relation between friendship instability and depressive symptoms would differ according to specific friendship status (best and secondary friendships) and contexts (school, non-school, and multiple). Participants were 102 young adolescents (51 girls; M age  =  12 years) who completed a series of five monthly telephone interviews and in-class questionnaires. Results suggested that friendship instability over a five-month period was significantly associated with an increase in depressed mood. Regarding the directionality of the influence, cross-lag analyses revealed that elevated depressive symptoms at one time point significantly predicted an increase in friendship instability by the following month, whereas friendship instability at one time point did not predict an increase in depressive symptoms the next month. Finally, participants' depressed mood appeared to be associated with instability in their best friendships (but not secondary friendships) and in their school friendships (but not non-school and multi-context friendships). The theoretical and practical implications of the results are discussed.