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Ray Thomas 《Significance》2004,1(2):60-63
Conventional unemployment statistics have two dimensions—size and date. Population-at-risk unemployment rates add a third dimension—time. They are unlikely to revolutionise our picture of the nature of unemployment, says Ray Thomas . But they do give a more accurate and comprehensive picture than existing measures, and provide new insights into old problems, such as indicating the importance of statistics of entrants in helping to explain geographical variation in unemployment. 相似文献
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Ray R 《Journal of population economics》1989,2(3):211-224
This study examines on United Kingdom budget data the sensitivity of policy and welfare conclusions to the introduction of quantity constraint on Housing demand within a utility consistent framework. The paper proposes a rationed demographic demand system, based on extension of the idea of virtual price, and presents evidence that such a model could prove useful in the precise estimation of equivalence scales on budget data with limited price variation. The demand parameter estimates and their welfare implications are quite sensitive to the introduction of rationed demand. Unlike in previous studies, the rationed demand system fails to reject linear preferences.I am grateful to Arie Kapteyn and an anonymous referee for helpful written comments on an earlier version. I also thank seminar participants at the Second Annual Congress of the European Society of Population Economics at the University of Mannheim, West Germany in June 1988, at the University of NSW and Melbourne in Australia, and Victoria University of Wellington in New Zealand for useful discussions. I retain responsibility for all errors that remain. 相似文献
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Dr. Diane Davis Ph.D. Dr. JoAnn Ray Ph.D. Claudette Sayles B.S.W. 《Child and Adolescent Social Work Journal》1994,12(6):445-463
Outdoor structured activities, such as Ropes Challenge Courses, are typically utilized as interventions for youth coming from urban settings. Evaluation of such programs is scanty at best. In this instance, the course experience is used as a prevention tool for high risk youth in a remote, rural setting of high unemployment, alcohol problems, and low income. The authors discuss the effectiveness of this approach, and the intended and unintended consequences for the rural community at large. The evaluation design relies on extensive qualitative methodology as well as quantitative methods to capture the unique nature of this rural project. 相似文献
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Ray JC 《Journal of European social policy》1997,7(1):5-16
"This study is based upon an international dataset comparing state support for families in fifteen countries (of which twelve are member states of the European Union).... Using multiple regression analysis, the levels of state support are explained by the principal parameters used for setting the levels of benefit, and by the demographic and economic characteristics of the countries concerned....[Results suggest] that the economic convergence of the member states is likely to promote greater similarity in their systems of state welfare support for families." (EXCERPT) 相似文献
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Logistic regression is estimated by maximizing the log-likelihood objective function formulated under the assumption of maximizing the overall accuracy. That does not apply to the imbalanced data. The resulting models tend to be biased towards the majority class (i.e. non-event), which can bring great loss in practice. One strategy for mitigating such bias is to penalize the misclassification costs of observations differently in the log-likelihood function. Existing solutions require either hard hyperparameter estimating or high computational complexity. We propose a novel penalized log-likelihood function by including penalty weights as decision variables for observations in the minority class (i.e. event) and learning them from data along with model coefficients. In the experiments, the proposed logistic regression model is compared with the existing ones on the statistics of area under receiver operating characteristics (ROC) curve from 10 public datasets and 16 simulated datasets, as well as the training time. A detailed analysis is conducted on an imbalanced credit dataset to examine the estimated probability distributions, additional performance measurements (i.e. type I error and type II error) and model coefficients. The results demonstrate that both the discrimination ability and computation efficiency of logistic regression models are improved using the proposed log-likelihood function as the learning objective. 相似文献