Uncertainty and Sensitivity Analysis in Assessment of the Thyroid Cancer Risk Related to Chernobyl Fallout in Eastern France

The increase in the thyroid cancer incidence in France observed over the last 20 years has raised public concern about its association with the 1986 nuclear power plant accident at Chernobyl. At the request of French authorities, a first study sought to quantify the possible risk of thyroid cancer associated with the Chernobyl fallout in France. This study suffered from two limitations. The first involved the lack of knowledge of spontaneous thyroid cancer incidence rates (in the absence of exposure), which was especially necessary to take their trends into account for projections over time; the second was the failure to consider the uncertainties. The aim of this article is to enhance the initial thyroid cancer risk assessment for the period 1991-2007 in the area of France most exposed to the fallout (i.e., eastern France) and thereby mitigate these limitations. We consider the changes over time in the incidence of spontaneous thyroid cancer and conduct both uncertainty and sensitivity analyses. The number of spontaneous thyroid cancers was estimated from French cancer registries on the basis of two scenarios: one with a constant incidence, the other using the trend observed. Thyroid doses were estimated from all available data about contamination in France from Chernobyl fallout. Results from a 1995 pooled analysis published by Ron et al. were used to determine the dose-response relation. Depending on the scenario, the number of spontaneous thyroid cancer cases ranges from 894 (90% CI: 869-920) to 1,716 (90% CI: 1,691-1,741). The number of excess thyroid cancer cases predicted ranges from 5 (90% UI: 1-15) to 63 (90% UI: 12-180). All of the assumptions underlying the thyroid cancer risk assessment are discussed.     

The impact of education on third births. A multilevel discrete-time hazard analysis

We propose to use multilevel discrete-time hazard models to assess the impact of societal and individual level covariates on the timing and occurrence of third births. We focus mainly on the impact of educational attainment on third births across 15 European countries. From the analysis in this paper, the effect of education on the propensity to have a third child is found to be negative. This education effect is not significantly weakened by the Nordic countries, but living in Scandinavia does increase the hazard for a third birth.     

Ratio-Scale Measurement with Intransitivity or Incompleteness: The Homogeneous Case

In the homogeneous case of one-dimensional objects, we show that any relation that is positive and homothetic can be represented by a ratio-scale and a unique and constant biasing factor. This factor may favor or disfavor the preference for an object over another. In the first case, preferences are complete but not transitive and an object may be preferred even when its value is lower. In the second case, preferences are asymmetric and transitive but not negatively transitive and it may not be sufficient for an object to have a greater value to be preferred. In this manner, the biasing factor reflects the extent to which preferences may depart from a maximization process.     

Scoring rules on dichotomous preferences

In this paper, we study individual incentives to report preferences truthfully for the special case when individuals have dichotomous preferences on the set of alternatives and preferences are aggregated in form of scoring rules. In particular, we show that (a) the Borda Count coincides with Approval Voting, (b) the Borda Count is the only strategy-proof scoring rule, and (c) if the size of the electorate is greater than three, then the dichotomous preference domain is the unique maximal rich domain under which the Borda Count is strategy-proof. I thank Jordi Massó for his supervision and his never-ending encouragement. Miguel-ángel Ballester showed me how to improve on earlier drafts of the paper. Salvador Barberà, Carmen Bevía, Bhaskar Dutta, Lars Ehlers, Alejandro Neme, Shmuel Nitzan and Yves Sprumont helped me a lot with their comments. All remaining errors are mine. This research was undertaken with support from the fellowship 2001FI 00451 of the Generalitat de Catalunya and from the research grant BEC2002-02130 of the Ministerio de Ciencia y Tecnología of Spain while I have been a graduate student at Universitat Autònoma de Barcelona.     

Deviant social positions in small groups: The relation between role and individual

This paper studies a deviant social position within a small group of Italian Fishermen. The role of “court-jester” emerges and, as the title suggests, the relation between this role and the inherent properties of the deviant are explored. It is argued that the emergence of roles among deviant social positions is dependent upon the personal attributes of the deviant and the characteristics of his relations to other members of the group.     

Inférence statistique dans les processus stochastiques: Aperçu historique

The study of statistical inference for stochastic processes has evolved along two paths. Some problems related to particular processes have been studied, and also some trials to extend general results obtained for independent identically distributed random variables have been made. We retrace the first main contributions, evaluate their influence, and give an idea of the evolution of the research in the field of statistical inference made with observations coming from a stochastic process.