[Show abstract][Hide abstract] ABSTRACT: Analysis of the occurrence of adverse events, and in particular of solicited symptoms, following vaccination is often needed for the safety and benefit-risk evaluation of any candidate vaccine, and typically involves taking repeated measurements. In this article, it is shown that Linear Categorical Marginal Models are well-suited to take the dependencies in the data arising from the repeated measurements into account and provide detailed and useful information for comparing safety profiles of different products while remaining relatively easy to interpret. Linear Categorical Marginal Models are presented and applied to a Phase III clinical trial of a candidate meningoccocal pediatric vaccine.
Statistics in Biopharmaceutical Research 02/2013; 5(1).
[Show abstract][Hide abstract] ABSTRACT: Epidemics are often modeled using non-linear dynamical systems observed through partial and noisy data. In this paper, we consider stochastic extensions in order to capture unknown influences (changing behaviors, public interventions, seasonal effects, etc.). These models assign diffusion processes to the time-varying parameters, and our inferential procedure is based on a suitably adjusted adaptive particle Markov chain Monte Carlo algorithm. The performance of the proposed computational methods is validated on simulated data and the adopted model is applied to the 2009 H1N1 pandemic in England. In addition to estimating the effective contact rate trajectories, the methodology is applied in real time to provide evidence in related public health decisions. Diffusion-driven susceptible exposed infected retired-type models with age structure are also introduced.
[Show abstract][Hide abstract] ABSTRACT: We model a defaultable asset as solution to a stochastic differential equation driven by both a Brownian motion and the counting process martingale associated to the one-jump process. We discuss in this framework the minimal entropy martingale measure as well as the linear Esscher and the minimal martingale measure. In particular we deal with some rather delicate verification issues.
Stochastic Processes and their Applications 08/2012; 122(8):2870–2884.
[Show abstract][Hide abstract] ABSTRACT: There is a duality theory connecting certain stochastic orderings between
cumulative distribution functions F_1,F_2 and stochastic orderings between
their inverses F_1^(-1),F_2^(-1). This underlies some theories of utility in
the case of the cdf and deprivation indices in the case of the inverse. Under
certain conditions there is an equivalence between the two theories. An example
is the equivalence between second order stochastic dominance and the Lorenz
ordering. This duality is generalised to include the case where there is
"distortion" of the cdf of the form v(F) and also of the inverse. A
comprehensive duality theorem is presented in a form which includes the
distortions and links the duality to the parallel theories of risk and
deprivation indices. It is shown that some well-known examples are special
cases of the results, including some from the Yaari social welfare theory and
the theory of majorization.
[Show abstract][Hide abstract] ABSTRACT: ABSTRACT: Observational studies of human health and disease (basic, clinical and epidemiological) are vulnerable to methodological problems -such as selection bias and confounding- that make causal inferences problematic. Gene-disease associations are no exception, as they are commonly investigated using observational designs. A rich body of knowledge exists in medicine and epidemiology on the assessment of causal relationships involving personal and environmental causes of disease; it includes seminal causal criteria developed by Austin Bradford Hill and more recently applied directed acyclic graphs (DAGs). However, such knowledge has seldom been applied to assess causal relationships in clinical genetics and genomics, even in studies aimed at making inferences relevant for human health. Conversely, incorporating genetic causal knowledge into clinical and epidemiological causal reasoning is still a largely unexplored area.As the contribution of genetics to the understanding of disease aetiology becomes more important, causal assessment of genetic and genomic evidence becomes fundamental. The method we develop in this paper provides a simple and rigorous first step towards this goal. The present paper is an example of integrative research, i.e., research that integrates knowledge, data, methods, techniques, and reasoning from multiple disciplines, approaches and levels of analysis to generate knowledge that no discipline alone may achieve.
[Show abstract][Hide abstract] ABSTRACT: We consider the indifference valuation of an uncertain monetary payoff from the perspective of an uncertainty averse decision maker. We study how the indifference valuation depends on the decision maker's attitudes toward uncertainty. We obtain a characterization of comparative uncertainty aversion and various characterizations of increasing, decreasing, and constant uncertainty aversion.
SSRN Electronic Journal 05/2011;
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