Influence of Routine Slaughtering on the Evolution of BSE: Example of British and French Slaughterings

The aim of this article is to build a methodology allowing the study and the comparison of the potential spread of BSE at the scale of countries under different routine slaughtering conditions in order to evaluate the risk of nonextinction due to this slaughtering. We first model the evolution in discrete time of the proportion of animals in the latent period and that of infectives, assuming a very large branching population not necessarily constant in size, two age classes, less than 1-year-old animals, and adult animals. We analytically derive a bifurcation parameter rho(0) allowing us to predict either endemicity or extinction of the disease, which has the meaning of an epidemiological reproductive rate. We show that the classical reproductive number R(0) cannot be used for prediction if the size of the population, when healthy, does not remain stable throughout time. We illustrate the qualitative results by means of simulations with either the British routine slaughtering probabilities or the French ones, the other conditions being assumed identical in both countries. We show that the French probabilities lead to a higher risk of spread of the disease than the British ones, this result being mainly due to a smaller value of the routine slaughtering probability of the adult animals in France than in Great Britain.     

The limiting distribution of the least-squares estimator in nearly integrated seasonal models

We consider the least-squares estimator of the autoregressive parameter in a nearly integrated seasonal model. Building on the study by Chan (1989), who obtained the limiting distribution, we derive a closed-form expression for the appropriate limiting joint moment generating function. We use this function to tabulate percentage points of the asymptotic distribution for various seasonal periods via numerical integration. The results are extended by deriving a stochastic asymptotic expansion to order O_p(T^-l), whose percentage points are also obtained by numerically integrating the appropriate limiting joint moment generating function. The adequacy of the approximation to the finite-sample distribution is discussed.     

Global Financial Crisis, Public Administration and Governance: Do New Problems Require New Solutions?

A financial crisis, or any crisis, is likely to produce a variety of responses from governments. This article discusses the range of responses that may be possible, pointing out that diametrically opposite answers may be made to the common problem. The analysis points to the persistence of many dichotomies in our thinking about public administration and public policy. These varied responses to crises are investigated in several political systems including the Baltic States and the European Union.     

Reflexive audiovisual methodology: The emergence of “minority practices” among pluriactive stock farmers

This paper proposes a new way for sociology, through both methodology and theory, to understand the reality of social groups and their “minority practices.” It is based on an experiment that concerns a very specific category of agriculturalists called “pluriactive” stock farmers. These stock farmers, who engage in raising livestock part-time alongside another full-time job, form a minority category within the agricultural profession.We address the question of how to analyze and represent the practices of this kind of “social” group or category through participatory filmmaking. Our research shows that beyond the collaborative production and screening of the film done in close cooperation with the stock farmers themselves, a second unexpected dynamic emerged around the sequences that were cut in the final editing round. These cut sequences reveal hesitations and disagreements among the breeders about their own practices in relation to their work and to animal welfare. These hesitations are not considered weaknesses, but rather as proof of the emergence of this group of stock farmers as “practitioners”. In the realm of intervention research, the participatory film-making process is attractive because it enables the farmers to raise new questions on their own, discuss them, and eventually resolve them, while also encouraging the researchers to identify the conditions that must be met in order to achieve this fragile linkage. This process and its outcomes force us to revisit the theoretical question of what constitutes a pragmatic definition of a “practice.”     

Measuring State TANF Policy Variations and Change After Reform*

Objectives. Our objectives are to describe the policies adopted after PRWORA, which vary across states, to test for common underlying policy concepts, demonstrating how these policies are interrelated, and to examine whether policy stringency diffused to neighboring states results in greater policy stringency across all states over time. We convert textual TANF welfare guidelines into empirically derived policy dimensions and use the derived quantitative scores to describe variation and change in welfare policy dimensions across status during the 1996–2003 post‐welfare‐reform period. Methods. Utilizing the Urban Institute's Welfare Rules Database, we apply a factor analytic methodology to 78 unique state policy guidelines that were coded on a lenient‐to‐stringent continuum. Regression analyses, employing spatial contiguity weighting, are used to describe policy diffusion. Results. The results identified 15 underlying first‐order post‐welfare‐reform policy dimensions, which for scientific parsimony were further reduced to three second‐order underlying dimensions representing rules governing eligibility: eligibility requirements for groups, behavioral responsibilities for maintaining eligibility, and eligibility time limits and exemptions. Analysis of the quantitative scores showed that by 2003 states had become more lenient regarding eligibility criteria for groups but decidedly more stringent regarding behavioral guidelines for maintaining eligibility and eligibility time limits and exemptions. Spatial clustering is not found globally but is significant for some states at the local level. Spatial diffusion is apparent only for behavioral rules. Conclusions. Our results suggest that TANF policy variations across states go beyond payment levels to include salient eligibility rules. The patterns of variability in change scores across states do not support a pervasive “race to the bottom” conclusion.     

Utility values in health technology assessments: a statistician's perspective

This paper provides an introduction to utilities for statisticians working mainly in clinical research who have not had experience of health technology assessment work. Utility is the numeric valuation applied to a health state based on the preference of being in that state relative to perfect health. Utilities are often combined with survival data in health economic modelling to obtain quality‐adjusted life years. There are several methods available for deriving the preference weights and the health states to which they are applied, and combining them to estimate utilities, and the clinical statistician has valuable skills that can be applied in ensuring the robustness of the trial design, data collection and analyses to obtain and handle this data. In addition to raising awareness of the subject and providing source references, the paper outlines the concepts and approaches around utilities using examples, discusses some of the key issues, and proposes areas where statisticians can collaborate with health economic colleagues to improve the quality of this important element of health technology assessment. Copyright © 2014 John Wiley & Sons, Ltd.     

Skew generalized extreme value distribution: Probability-weighted moments estimation and application to block maxima procedure

ABSTRACT

Following the work of Azzalini (1985 Azzalini, A. (1985). A class of distributions which includes the normal ones. Scand. J. Stat. 12:171–178.[Web of Science ®] , [Google Scholar] and 1986 Azzalini, A. (1986). Further results on a class of distributions which includes the normal ones. Statistica 46:199–208. [Google Scholar]) on the skew-normal distribution, we propose an extension of the generalized extreme value (GEV) distribution, the SGEV. This new distribution allows for a better fit of maxima and can be interpreted as both the distribution of maxima when maxima are taken on dependent data and when maxima are taken over a random block size. We propose to estimate the parameters of the SGEV distribution via the probability-weighted moment method. A simulation study is presented to provide an application of the SGEV on block maxima procedure and return level estimation. The proposed method is also implemented on a real-life data.     

A Time-Series Study of the Formation and Predictive Performance of EEC Production Survey Expectations

Generalized method of moments (GMM) has been an important innovation in econometrics. Its usefulness has motivated a search for good inference procedures based on GMM. This article presents a novel method of bootstrapping for GMM based on resampling from the empirical likelihood distribution that imposes the moment restrictions. We show that this approach yields a large-sample improvement and is efficient, and give examples. We also discuss the development of GMM and other recent work on improved inference.