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排序方式: 共有433条查询结果,搜索用时 15 毫秒
1.
Bayesian networks for imputation 总被引:1,自引:0,他引:1
Marco Di Zio Mauro Scanu Lucia Coppola Orietta Luzi Alessandra Ponti 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》2004,167(2):309-322
Summary. Bayesian networks are particularly useful for dealing with high dimensional statistical problems. They allow a reduction in the complexity of the phenomenon under study by representing joint relationships between a set of variables through conditional relationships between subsets of these variables. Following Thibaudeau and Winkler we use Bayesian networks for imputing missing values. This method is introduced to deal with the problem of the consistency of imputed values: preservation of statistical relationships between variables ( statistical consistency ) and preservation of logical constraints in data ( logical consistency ). We perform some experiments on a subset of anonymous individual records from the 1991 UK population census. 相似文献
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Major policy changes like the 1986 Tax Reform Act (TRA) in the United States provide natural experiments to study attitudinal and behavior responses to law. Surprisingly, public evaluations of the TRA became increasingly negative after passage, while general support for the tax system became more positive in response to the changes. To explain this puzzle, we propose a dynamic model of taxpayer attitudes that is consistent with the observed loose linkage between logically-connected concepts. We briefly review the political context, objectives and impacts of the 1986 Tax Reform Act, and present several studies testing the impact of self-interest, prior beliefs, and social discussion on changes in attitudes and behavior.Results suggest that the complexity of taxes and difficulty in knowing objective impacts weakens the role of self-interest in attitudinal changes, thereby strengthening the role of prior beliefs and discussion. Evaluations of tax laws are most responsive to more politically-oriented influences. 相似文献
3.
Marco Bee 《Statistical Methods and Applications》2005,14(1):127-141
In this article we provide a rigorous treatment of one of the central statistical issues of credit risk management. GivenK-1 rating categories, the rating of a corporate bond over a certain horizon may either stay the same or change to one of the
remainingK-2 categories; in addition, it is usually the case that the rating of some bonds is withdrawn during the time interval considered
in the analysis. When estimating transition probabilities, we have thus to consider aK-th category, called withdrawal, which contains (partially) missing data. We show how maximum likelihood estimation can be
performed in this setup; whereas in discrete time our solution gives rigorous support to a solution often used in applications,
in continuous time the maximum likelihood estimator of the transition matrix computed by means of the EM algorithm represents
a significant improvement over existing methods. 相似文献
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The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software. 相似文献
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Marco Francesconi 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》2005,168(3):539-566
Summary. The paper performs an evaluation of the data that were collected in the sixth wave of the British Household Panel Survey (BHPS) on childhood family structure. After comparing such data with a large number of studies by using external sources, we find that the BHPS data overestimate the proportion of people who report an experience of life in a non-intact family during childhood by about 10%. Although an explanation based on recall error that deteriorates with the age of the BHPS respondents is possible, the overestimation is likely to be accounted for by non-ignorable attrition that may affect most of the comparison studies based on longitudinal data. Conversely, comparisons with other independent measurements from the BHPS itself reveal that the wave 6 data underestimate the proportion of young people who have lived at least part of their childhood in a non-intact family by about 8%. The probability of disagreement between these two sets of measures is strongly associated with poor interview characteristics, which may affect the comparison measure more than the wave 6 measure. Despite such differences, there is therefore a substantial degree of similarity between the family structure information that was collected in the sixth wave of the BHPS and the host of highly diverse records against which it has been compared. 相似文献
9.
Mariacristina Piva Massimiliano Tani Marco Vivarelli 《Journal of population economics》2018,31(4):1321-1338
We investigate whether labor mobility can be a distinct source of growth by studying the productivity impact of business visits (BVs), vis-à-vis that of other well-known drivers of productivity enhancement. Our analysis uses an unbalanced panel—covering on average 16 sectors per year in ten countries during the period 1998–2011—which combines unique and novel data on BVs sourced from the US National Business Travel Association with Organization for Economic Cooperation and Development (OECD) data on R&D and capital formation. We find that mobility through BVs is an effective mechanism to improve productivity, being about half that obtained by investing in R&D. This relevant finding invites viewing short-term mobility as a strategic mechanism and prospective policy tool to overcome productivity slowdowns and foster economic growth. 相似文献
10.
Arcagni Alberto Barbiano di Belgiojoso Elisa Fattore Marco Rimoldi Stefania M. L. 《Social indicators research》2019,141(2):551-579
Social Indicators Research - In this paper, we present a multidimensional fuzzy analysis of the levels and the patterns of poverty and social fragility of migrants’ families, in the Italian... 相似文献