A hierarchical Bayesian approach to record linkage and population size problems

We propose and illustrate a hierarchical Bayesian approach for matching statistical records observed on different occasions. We show how this model can be profitably adopted both in record linkage problems and in capture--recapture setups, where the size of a finite population is the real object of interest. There are at least two important differences between the proposed model-based approach and the current practice in record linkage. First, the statistical model is built up on the actually observed categorical variables and no reduction (to 0--1 comparisons) of the available information takes place. Second, the hierarchical structure of the model allows a two-way propagation of the uncertainty between the parameter estimation step and the matching procedure so that no plug-in estimates are used and the correct uncertainty is accounted for both in estimating the population size and in performing the record linkage. We illustrate and motivate our proposal through a real data example and simulations.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS447 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Comparing parametric and semi-parametric approaches for bayesian cost-effectiveness analyses in health economics

We consider the problem of assessing new and existing technologies for their cost-effectiveness in the case where data on both costs and effects are available from a clinical trial, and we address it by means of the cost-effectiveness acceptability curve. The main difficulty in these analyses is that cost data usually exhibit highly skew and heavytailed distributions, so that it can be extremely difficult to produce realistic probabilistic models for the underlying population distribution, and in particular to model accurately the tail of the distribution, which is highly influential in estimating the population mean. Here, in order to integrate the uncertainty about the model into the analysis of cost data and into cost-effectiveness analyses, we consider an approach based on Bayesian model averaging: instead of choosing a single parametric model, we specify a set of plausible models for costs and estimate the mean cost with its posterior expectation, that can be obtained as a weighted mean of the posterior expectations under each model, with weights given by the posterior model probabilities. The results are compared with those obtained with a semi-parametric approach that does not require any assumption about the distribution of costs. 1 IntroductionHealthcare cost data, cost-effectiveness analysis, mixture models, Bayesian model averaging

A unified framework for de-duplication and population size estimation (with Discussion)

Data de-duplication is the process of finding records in one or more datasets belonging to the same entity. In this paper we tackle the de-duplication process via a latent entity model, where the observed data are perturbed versions of a set of key variables drawn from a finite population of $N$ different entities. The main novelty of our approach is to consider the population size $N$ as an unknown model parameter. As a result, one salient feature of the proposed method is the capability of the model to account for the de-duplication uncertainty in the population size estimation. As by-products of our approach we illustrate the relationships between de-duplication problems and capture-recapture models and we obtain a more adequate prior distribution on the linkage structure. Moreover we propose a novel simulation algorithm for the posterior distribution of the matching configuration based on the marginalization of the key variables at the population level. We apply our approach to two synthetic data sets comprising German names. In addition we illustrate a real data application matching records from two lists reporting victims killed in the recent Syrian conflict

Accounting for heavy tails in stochastic frontier models.

This paper aims at introducing a new class of stochastic frontier models that can take account for fat tails composed errore. Quite surprisingly, all the stochastic frontier models proposed in literature cannot handle situations where the empirical distribution of the composed error has heavy tails. These situations are instead very common in applications. In particular, we will propose to model the composed error with the skew-t distribution. This is equivalent to assume a Student-t distribution for the measurement error and a half-t distribution for the inefficiency. In this way, we extend quite naturally, the stochastic frontier model where a normal distribution is assumed for the symmetric error and a half-normal distribution is assumed for the inefficiency term

A bayesian semi-parametric approach for cost-effectiveness analysis in health economics

We consider the problem of assessing new and existing technologies for their cost-effectiveness in the case where data on both costs and efficacy are available from a clinical trial, and we address it by means of the cost-effectiveness acceptability curve in the simple case where efficacy is measured as a binary outcome. We consider a Bayesian approach, and in recognising that cost data usually exhibit highly skew, heavy-tailed and, possibly multi-modal distributions, we introduce a model for costs composed of a piecewise constant density up to an unknown endpoint, and a generalised Pareto distribution for the remaining tail.Healthcare cost data, cost-effectiveness analysis, mixture models, semiparametric modelling.

Direito e saúde: a discricionariedade nas ações fiscais da vigilância sanitária de alimentos

A Ciência do Direito orienta-se por princípios os quais constituem a base que rege todas as relações jurídicas existentes. À Vigilância Sanitária e ao Sistema Único de Saúde cabem a responsabilidade pelas ações de fiscalização e inspeção de alimentos, bebidas, águas de consumo, embalagens e matérias-primas alimentares, além dos estabelecimentos industriais e comerciais de alimentos, com o propósito de prevenir riscos à saúde do consumidor. As normas jurídicas sobre alimentos são complexas e abrangentes e, em várias situações, não muito claras, delegando ao agente responsável pela ação fiscal a interpretação do texto legislativo e a aplicabilidade da sanção ou penalidade que melhor couber ao caso. Busca-se neste trabalho, identificar e compreender a utilização dos atos administrativos enquanto normas aplicadas à Vigilância Sanitária, no Sistema Federativo Brasileiro, no desenvolvimento das atividades rotineiras. Conclui-se que a discricionariedade administrativa, permitida nas ações fiscais da Vigilância Sanitária, justifica-se pela ampla variedade e quantidade de problemas a serem equacionados pelos agentes na sua jornada de trabalho, para os quais a lei, por mais abrangente e completa, nem sempre tem respostas, cabendo aos agentes tomar as medidas mais adequadas a cada caso, de acordo com o seu conhecimento técnico-científico e senso comum

Magnitude and size distribution of long-period comets in Earth-crossing or approaching orbits

We analyse the population of near-Earth Long-Period Comets (LPCs) (perihelion distances q 10^3 yr). We have considered the sample of LPCs discovered during the period 1900-2009 and their estimated absolute total visual magnitudes H. For the period 1900-1970 we have relied upon historical estimates of absolute total magnitudes, while for the more recent period 1970-2009 we have made our own estimates of H based on Green's photometric data base and IAU Circulars. We have also used historical records for the sample of brightest comets (H < 4.5) covering the period: 1500-1899, based mainly on Vsekhsvyatskii, Hasegawa and Kronk catalogues. We find that the cumulative distribution of H can be represented by a three-modal law of the form log_{10}N_{<H} = C + alpha times H, where the C's are constants for the different legs, and alpha \simeq 0.28 +/- 0.10 for H < 4.0, alpha \simeq 0.56 +/- 0.10 for 4.0 <= H < 5.8, and alpha \simeq 0.20 +/- 0.02 for 5.8 <= H <8.6. The large increase of the slope of the second leg of the H-distribution might be at least partially attributed to splitting of comet nuclei leading to the creation of two or more daughter comets. The cumulative H-distribution tends to flatten for comets fainter than H <= 8.6. LPCs fainter than H <= 12 (or diametres D \lesssim 0.5 km) are extremely rare, despite several sky surveys of near-Earth objects implemented during the last couple of decades, suggesting a minimum size for a LPC to remain active. We also find that about 30 % of all LPCs with q < 1.3 AU are new (original bound energies 0 < E_{or} < 10^{-4} AU^{-1}), and that among the new comets about half come from the outer Oort cloud (energies 0 \lesssim E_{or} \lesssim 0.3 times 10^{-4} AU^{-1}), and the other half from the inner Oort cloud (energies 0.3 times 10^{-4} \lesssim E_{or} \lesssim 10^{-4}AU^{-1}).Comment: 31 pages, 12 figures, MNRAS accepte

Sex Differences in Autism Spectrum Disorder: An Investigation on Core Symptoms and Psychiatric Comorbidity in Preschoolers

Findings regarding sex differences in autism spectrum disorder (ASD), as far as core symptoms and psychiatric comorbidities (PC) are concerned, are inconsistent, inconclusive, or conflicting among studies. The lower prevalence of ASD in females than in males and the age and intelligence quotient (IQ) heterogeneity among samples made it difficult to investigate these differences. This case–control study tries to deepen the impact of sex differences on core symptoms of autism and PC in 214 preschoolers with ASD (mean age, 45.26) without impairment in non-verbal IQ (nvIQ ≥70). A total of 107 ASD females (mean age, 44.51 ± 13.79 months) were matched one by one with 107 males (mean age, 46.01 ± 13.42 months) for chronological age (±6 months) and nvIQ (±6 points). We used the Autism Diagnostic Observation Schedule 2 (ADOS-2) and the Child Behavior Checklist (CBCL) 1.5–5 to explore autism severity and PC. The results highlight that ASD females did not significantly differ from ASD males regarding the severity of autism. Statistically significant lower levels of emotionally reactive (p = 0.005, η2 = 0.04), anxious-depressed (p = 0.001, η2 = 0.05), internalizing problems (p = 0.04, η2 = 0.02), and DSM-Oriented Scales anxiety problems (p = 0.02, η2 = 0.04) in ASD females than in ASD males were also detected. Our findings of no difference in the autism severity and lower internalizing problems in females than males with ASD extend the knowledge of autism in females during preschool years. Compared to other similar studies on this topic, we can state that these results are not supported by differences in nvIQ between sexes nor by the presence of cognitive impairment. It confirms the need for clinicians to consider sex differences when describing autism psychopathology

Theranostic biomarkers and PARP-inhibitors effectiveness in patients with non-BRCA associated homologous recombination deficient tumors: Still looking through a dirty glass window?

: Breast cancer susceptibility gene 1 (BRCA1) and breast cancer susceptibility gene 2 (BRCA2) deleterious variants were the first and, still today, the main biomarkers of poly(ADP)ribose polymerase (PARP)-inhibitors (PARPis) benefit. The recent, increased, numbers of individuals referred for counseling and multigene panel testing, and the remarkable expansion of approved PARPis, not restricted to BRCA1/BRCA2-Pathogenic Variants (PVs), produced a strong clinical need for non-BRCA biomarkers. Significant limitations of the current testing and assays exist. The different approaches that identify the causes of Homologous Recombination Deficiency (HRD), such as the germline and somatic Homologous Recombination Repair (HRR) gene PVs, the testing showing its consequences, such as the genomic scars, or the novel functional assays such as the RAD51 foci testing, are not interchangeable, and should not be considered as substitutes for each other in clinical practice for guiding use of PARPi in non-BRCA, HRD-associated tumors. Today, the deeper knowledge on the significant relationship among all proteins involved in the HRR, not limited to BRCA, expands the possibility of a successful non-BRCA, HRD-PARPi synthetic lethality and, at the same time, reinforces the need for enhanced definition of HRD biomarkers predicting the magnitude of PARPi benefit