A class of neutral to the right priors induced by superposition of beta processes

A random distribution function on the positive real line which belongs to the class of neutral to the right priors is defined. It corresponds to the superposition of independent beta processes at the cumulative hazard level. The definition is constructive and starts with a discrete time process with random probability masses obtained from suitably defined products of independent beta random variables. The continuous time version is derived as the corresponding infinitesimal weak limit and is described in terms of completely random measures. It takes the interpretation of the survival distribution resulting from independent competing failure times. We discuss prior specification and illustrate posterior inference on a real data example.     

Definitions and linkages between operational and strategic flexibilities

This paper aims at clarifying the concept of strategic flexibility, starting from that much more common of manufacturing flexibility (or operational one). After characterizing the dimensions of the latter, a classification of strategic flexibility is presented which distinguishes four categories. The measures of strategic flexibility are also investigated. Then two analogies are pointed out with the operational flexibility. The first, of the cause-effect type, is on two levels: at the business level, the operational flexibility estimates the variation of practices, while the strategic flexibility measures the effect obtained on performances; at the corporate level, the operational flexibility estimates the variation of competences, while the strategic flexibility evaluates the change in business. The second analogy, related to the classification variables, permits the main types of operational and strategic flexibilities to be placed in a single framework. So this study seeks to provide a framework—which has not been proposed in prior literature—for analyzing and evaluating the correlated concepts of operational and strategic flexibilities, to create a theoretical foundation for future research and empirical testing.     

Winding Stairs: A sampling tool to compute sensitivity indices

Sensitivity analysis aims to ascertain how each model input factor influences the variation in the model output. In performing global sensitivity analysis, we often encounter the problem of selecting the required number of runs in order to estimate the first order and/or the total indices accurately at a reasonable computational cost. The Winding Stairs sampling scheme (Jansen M.J.W., Rossing W.A.H., and Daamen R.A. 1994. In: Gasman J. and van Straten G. (Eds.), Predictability and Nonlinear Modelling in Natural Sciences and Economics. pp. 334–343.) is designed to provide an economic way to compute these indices. The main advantage of it is the multiple use of model evaluations, hence reducing the total number of model evaluations by more than half. The scheme is used in three simulation studies to compare its performance with the classic Sobol' LP. Results suggest that the Jansen Winding Stairs method provides better estimates of the Total Sensitivity Indices at small sample sizes.     

Economic growth,labour flexibilization and employment quality in Colombia, 2002–11

Over the period 2002–11, the Colombian labour market saw a marked improvement in employment opportunities, accompanied by an increase in nonstandard forms of employment. The authors look at how this affected employment quality, using a composite index based on Categorical Principal Components Analysis (CATPCA). They observe a small but widespread improvement in employment quality – mainly for self‐employed women – brought about by higher earnings, increased social protection and less time‐related underemployment. However, a considerable “quality deficit” remains, which calls for policies to strengthen labour market institutions and stimulate productivity and investment.     

Objective Bayes Covariate‐Adjusted Sparse Graphical Model Selection

We present an objective Bayes method for covariance selection in Gaussian multivariate regression models having a sparse regression and covariance structure, the latter being Markov with respect to a directed acyclic graph (DAG). Our procedure can be easily complemented with a variable selection step, so that variable and graphical model selection can be performed jointly. In this way, we offer a solution to a problem of growing importance especially in the area of genetical genomics (eQTL analysis). The input of our method is a single default prior, essentially involving no subjective elicitation, while its output is a closed form marginal likelihood for every covariate‐adjusted DAG model, which is constant over each class of Markov equivalent DAGs; our procedure thus naturally encompasses covariate‐adjusted decomposable graphical models. In realistic experimental studies, our method is highly competitive, especially when the number of responses is large relative to the sample size.     

Barriers and Enablers to Safeguarding Children and Adults within a Disability Services Context: Insights from an Australian Delphi Study

Research conducted in the 1990s revealed the tragic irony that exposure to the disability support system, and particularly to its institutional forms, was a major risk factor related to the neglect and abuse of children and adults with a disability. Subsequently, a range of policies have been introduced to minimize risk. However, recurring events of abuse and neglect in the disability services sector in high and middle income countries demonstrate that processes geared to safeguard children and adults with a disability from abuse and neglect remain insufficient. To establish the wider fabric of organizational factors that contribute to effective safeguarding practices within the Australian disability support sector, a modified online Delphi study was conducted, capturing the views of disability services staff and managers (n = 249) regarding barriers and enablers to effective safeguarding. This study identified issues concerning organizational culture, management practice, workforce development, client capacity building and contextual factors. During Round Two of the Delphi, participants were asked to rate the categorized enabler statements according to importance on a 10‐point Likert scale, to ascertain the degree of consensus. A total of 262 of the statements were regarded as important or very important. The Delphi result highlighted the considerable gap between the wider systemic and cultural processes that, in the eyes of disability services staff and management, contribute to good safeguarding practice and the safeguarding measures currently in place. The article calls for a holistic approach to safeguarding that addresses procedural issues and to the transformation of the wider systemic and cultural fabric of an organization.     

Leveraging global sources of knowledge for business model innovation

This article explores the concept of leveraging global knowledge for business model innovation, whereby knowledge is transferred across space and firm boundaries for the reconfiguration of an incumbent firm's business model. Considering the implications of an ever-increasing fragmentation of global value chains and the associated dispersion of global knowledge sources, we propose that supply chain partners at foreign locations can provide valuable knowledge that incumbents can leverage to change their business model. Integrating insights from global supply chain, business model, and organizational learning literature, we theorize and empirically test how different organizational capabilities enable firms to acquire knowledge from foreign partners, integrate external with internal knowledge, transform knowledge through experimentation, and finally apply global knowledge in the form of business model innovation. We conclude with suggestions for future research.     

On the volume-ranking of opportunity sets in economic environments

We provide a characterization of the volume-ranking of opportunity sets as defined on the set of all polyconvex sets, i.e. finite unions of convex, compact, Euclidean sets. In fact, such a domain is large enough to encompass most of the opportunity sets typically encountered in economic environments, including non-linear or even non-convex budget sets, and opportunity sets arising from production sets. Our result relies on a valuation-based volume-characterization theorem due to Klain and Rota (Introduction to Geometric Probability, Cambridge University Press, Cambridge, 1997) and helps to highlight some quite unusual conditions under which the volume-ranking can be justified as a freedom-ranking of opportunity sets. Therefore, it may also help to understand why the latter has been so conspicuously ignored in welfare analysis. Thanks are due to Larry Kranich, Massimo Marinacci, Uri Rothblum, Ernesto Screpanti, John Weymark, Yongsheng Xu, Claudio Zoli and two anonymous referees for helpful comments and suggestions.