Modelling interval data with Normal and Skew-Normal distributions

A parametric modelling for interval data is proposed, assuming a multivariate Normal or Skew-Normal distribution for the midpoints and log-ranges of the interval variables. The intrinsic nature of the interval variables leads to special structures of the variance–covariance matrix, which is represented by five different possible configurations. Maximum likelihood estimation for both models under all considered configurations is studied. The proposed modelling is then considered in the context of analysis of variance and multivariate analysis of variance testing. To access the behaviour of the proposed methodology, a simulation study is performed. The results show that, for medium or large sample sizes, tests have good power and their true significance level approaches nominal levels when the constraints assumed for the model are respected; however, for small samples, sizes close to nominal levels cannot be guaranteed. Applications to Chinese meteorological data in three different regions and to credit card usage variables for different card designations, illustrate the proposed methodology.     

Evaluating Marginal Policy Changes and the Average Effect of Treatment for Individuals at the Margin

This paper develops methods for evaluating marginal policy changes. We characterize how the effects of marginal policy changes depend on the direction of the policy change, and show that marginal policy effects are fundamentally easier to identify and to estimate than conventional treatment parameters. We develop the connection between marginal policy effects and the average effect of treatment for persons on the margin of indifference between participation in treatment and nonparticipation, and use this connection to analyze both parameters. We apply our analysis to estimate the effect of marginal changes in tuition on the return to going to college.     

MATERNAL EDUCATION,HOME ENVIRONMENTS,AND THE DEVELOPMENT OF CHILDREN AND ADOLESCENTS

We study the intergenerational effects of maternal education on children’s cognitive achievement, behavioral problems, grade repetition, and obesity, using matched data from the female participants of the National Longitudinal Survey of Youth 1979 (NLSY79) and their children. We address the endogeneity of maternal schooling by instrumenting it with variation in schooling costs during the mother’s adolescence. Our results show substantial intergenerational returns to education. Our data set allows us to study a large array of channels which may transmit the effect of maternal education to the child, including family environment and parental investments at different ages of the child. We discuss policy implications and relate our findings to the literature on intergenerational mobility.     

The pull evolution: from Kanban to customised token-based systems

This work formalises a new approach for material flow control, i.e. the so-called customised token-based systems (CTBS). This approach represents a natural evolution from classical pull systems, such as Kanban. The article first describes the flow of materials (orders or tasks) from a management point of view, and discusses exact and approximate approaches to tackle the problem. The origin of Customised Production Control systems is explained, as well as the main advantages: high degree of generalisation, enhancement of the space of solutions and adaptation to the manufacturing environment. Next, we propose a method based on cross-entropy for the optimisation of CTBS. The computational experience carried out in a number of scenarios shows the CTBS to be profitable. Furthermore, the resulting control mechanisms seem to be relatively easy to implement in real-manufacturing environments.     

Corporate and managerial characteristics as drivers of social responsibility disclosure by state-owned enterprises

The public administration sector, including state owned enterprises (SOEs), has developed various types of information disclosure practice, in response to stakeholders’ demands, in parallel with developments in the private sector. This paper analyses the corporate social responsibility (CSR) information disclosed by SOEs and the influence exerted by the characteristics of the SOEs themselves (size, industry sector, degree of government ownership and number of years in operation) and by those of their managers (age, gender, CSR education profile and CSR responsibilities in the workplace). To do so, an index of CSR information disclosure was created, based on the responses made to a questionnaire in this respect. An empirical regression model was then applied to test and categorise the factors analysed. According to the results obtained, the size and sector of the SOE, together with the manager’s CSR responsibilities, are the factors that most significantly affect the online disclosure of CSR information.     

The structure of global centrality measures

The aim of this article is to identify and analyse the logic and structure of centrality measures applied to social networks. On the basis of the article by Borgatti and Everett, identifying the latent functions of centrality, we first use a survey of personal networks with 450 cases to perform an empirical study of the differences and correspondences between degree, closeness and betweenness centrality in personal networks. Then, we examine the correspondences between the three global indicators in each type of centrality: the maximum value, the mean value and the hierarchy or centralization. The results provide a better understanding of the centrality indicators of networks and the reality that they express in an empirical context.     

Improved Exponential Type Estimators of the Mean of a Sensitive Variable in the Presence of Nonsensitive Auxiliary Information

Recently, Koyuncu et al. (2013 Koyuncu, N., Gupta, S., Sousa, R. (2014). Exponential type estimators of the mean of a sensitive variable in the presence of non-sensitive auxiliary information. Communications in Statistics- Simulation and Computation[PubMed], [Web of Science ®] , [Google Scholar]) proposed an exponential type estimator to improve the efficiency of mean estimator based on randomized response technique. In this article, we propose an improved exponential type estimator which is more efficient than the Koyuncu et al. (2013 Koyuncu, N., Gupta, S., Sousa, R. (2014). Exponential type estimators of the mean of a sensitive variable in the presence of non-sensitive auxiliary information. Communications in Statistics- Simulation and Computation[PubMed], [Web of Science ®] , [Google Scholar]) estimator, which in turn was shown to be more efficient than the usual mean estimator, ratio estimator, regression estimator, and the Gupta et al. (2012 Gupta, S., Shabbir, J., Sousa, R., Corte-Real, P. (2012). Regression estimation of the mean of a sensitive variable in the presence of auxiliary information. Communications in Statistics – Theory and Methods 41:2394–2404.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) estimator. Under simple random sampling without replacement (SRSWOR) scheme, bias and mean square error expressions for the proposed estimator are obtained up to first order of approximation and comparisons are made with the Koyuncu et al. (2013 Koyuncu, N., Gupta, S., Sousa, R. (2014). Exponential type estimators of the mean of a sensitive variable in the presence of non-sensitive auxiliary information. Communications in Statistics- Simulation and Computation[PubMed], [Web of Science ®] , [Google Scholar]) estimator. A simulation study is used to observe the performances of these two estimators. Theoretical findings are also supported by a numerical example with real data. We also show how to, extend the proposed estimator to the case when more than one auxiliary variable is available.     

When stressors make you work: Mechanisms linking challenge stressors to performance

Based on previous empirical findings, “challenge stressors” (Cavanaugh, Boswell, Roehling, & Bouderau, 2000 Cavanaugh, M. A., Boswell, W. R., Roehling, M. V., & Boudreau, J. W. (2000). An empirical examination of self-reported work stress among U.S. managers. Journal of Applied Psychology, 85, 65–74. doi:10.1037/0021-9010.85.1.65[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Lepine, Podsakoff, & Lepine, 2005 LePine, J. A., Podsakoff, N. P., & LePine, M. A. (2005). A meta-analytic test of the challenge stressor hindrance stressor framework: An explanation for inconsistent relationships among stressors and performance. Academy of Management Journal, 48, 764–775. doi: 10.5465/AMJ.2005.18803921[Crossref], [Web of Science ®] , [Google Scholar]), such as the amount and scope of responsibility, can be loosely considered as “good stressors” that are consistently and positively related to job satisfaction and performance. We introduce the role of appraisal to further examine how challenge stressors are connected to performance. Structural equation modelling analyses using an applied sample of 284 employee–supervisor dyads showed that affective commitment to the organization mediated the relationship between both opportunity and threat appraisal and performance (in-role and extra-role). The mediating role of increased psychosomatic distress was supported only for the relationship between threat appraisal and in-role performance. The findings indicate the importance of taking into account the actual appraisal of “challenge stressors”, as it carries implications for performance, and reveals the key role of affective commitment and induced distress mechanisms in this relationship. In conclusion, “challenge stressors” are not always positively related to performance, but only when they are perceived as opportunities.     

TimeOut@UCLA: An Intergenerational Respite Care and Workforce Development Program

TimeOut@UCLA is an intergenerational program that recruits undergraduate college students to provide companionship to older adults with early Alzheimer’s or other forms of dementia in a community setting, providing respite for their caregivers. In the program, 86 students and 89 seniors participated from September 2015 to December 2016. This program appears to reinforce positive attitudes about working with older adults among undergraduate students and gives caregivers an innovative option for respite time.