Simultaneous Confidence Intervals for the Difference of Two Survival Functions

In comparing two treatments with failure time observations, confidence bands for the "difference" of two survival curves provide useful information about a global picture of the treatment difference over time. In this note, we propose a rather simple procedure for constructing such simultaneous confidence intervals. Our technique can also be used in the one-sample case, which has been extensively studied in the literature.     

Rényi statistics for testing hypotheses in mixed linear regression models

Rényi divergences are used to propose some statistics for testing general hypotheses in mixed linear regression models. The asymptotic distribution of these tests statistics, of the Kullback–Leibler and of the likelihood ratio statistics are provided, assuming that the sample size and the number of levels of the random factors tend to infinity. A simulation study is carried out to analyze and compare the behavior of the proposed tests when the sample size and number of levels are small.     

Mimetic contagion and speculative bubbles

Conclusion The present essay has focused on specularity as a type of intersubjectivitywithin self-referential systems. We have stressed the self-organizationaldimension of specular processes, which lead to the emergenceof collective objects around which the group structures itself. Rationalbubbles, sunspots, and conventions provided us with examples of thiskind of self-organization within self-referential groups. It seems thatwe have here a theoretical schema that can account for numeroussocial institutions. Such is the case with money, which the overlappinggenerations model shows to belong to the same problematic. We haveobserved that individual and collective representations play an essentialrole in the definition of specular dynamics. In fact, giving thecollectivity a means of interpreting and understanding the natural andsocial environment is a crucial function of these representations. Inspite of its great importance, this cognitive dimension of collectiverepresentations has hardly been explored in previous theorizing. Wehave given priority to a specific form of specularity, namely, mimetism,which is in our view at the very heart of financial processes. Far frombeing the aberration that traditional approaches deem it to be, imita-tion is one of the most important types of rationality in situations ofuncertain and in situations where the agents' outcomes are highlyinterdependent. Our central hypothesis amounts to considering thatthe emergence of speculative bubbles on various kinds of markets canbe explained in terms of mimetic dynamics. Should this hypothesis beconfirmed, it would be possible to account for a phenomenon that isoften observed, namely, the link between bubbles and a decrease inthe diversity of opinion on the market. In our approach, conventionsare taken to be the outcome of a mimetic process. Conventions are thesocial objects created by a unanimous mimetic polarization.     

Bivariate income distributions with lognormal conditionals

In this paper, the most general bivariate distribution with lognormal conditionals is fully characterized, using the methodology proposed by [3]. The properties of the new family are studied in detail, including marginal and conditional distributions, regression functions, dependence measures, moments and inequality measures. The new distribution is very broad, and contains as a particular case the classical bivariate lognormal distribution. Several subfamilies are studied and a generalization of the basic model is discussed. Finally, we present an empirical application. We estimate and compare the basic model proposed in the paper with a classical model, using data from the European Community Household Panel in different periods of time.     

Putting the First Audience First: Conducting Useful Evaluation for a Risk-Related Government Agency

The risk communication practitioner in a government agency has two essential, interdependent tasks. One is to help develop and monitor effective communication programs with various external public audiences. The other task is to do the same thing for the senior government managers whose support is a prerequisite to addressing the first audience. Hence, the second audience–the manager–is really the first. This paper addresses ways in which communication practitioners can satisfy this crucial audience. A profile of these managers suggests that they would find it highly beneficial to have more control over the public problems they encounter, especially in view of the growing pressures to do more with less and demonstrate "customer satisfaction." They would rather avoid crises than manage them. And they would rather have their bosses praise their successes than challenge their budgets or punish their perceived difficulties or failures. Communication practitioners who can help them attain such benefits will find their efforts in great demand. They would be helpful team members who provide timely insights that can make and show agency success. We offer ten ways for communication practitioners to be more useful which focus their current strengths on satisfying senior managers'needs by becoming more valuable members of the program team. By becoming more useful to the senior manager they serve both the agency and its publics.     

Will They Ever Converge? Earnings of Immigrant and Canadian-born Workers over the Last Two Decades1

Using Census data covering the 1980–2000 period, this article examines what outcomes would be necessary for today's recent immigrant cohorts to achieve earnings parity with Canadian‐born workers. Our results show that today's recent immigrants would have to experience a drastic steepening of their relative age‐earnings profile in the near future for their earnings to converge with their Canadian‐born counterparts. The reason is simple: the greater relative earnings growth experienced by recent immigrant cohorts has only partially offset the drastic deterioration in their relative earnings at entry.