The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform
Patrick Moyes - One of the best experts on this subject based on the ideXlab platform.
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Ranking distributions of an Ordinal Variable
Economic Theory, 2020Co-Authors: Nicolas Gravel, Brice Magdalou, Patrick MoyesAbstract:We establish an equivalence between three criteria for comparing distributions of an Ordinal Variable taking finitely many values. The first criterion is the possibility of going from one distribution to the other by a finite sequence of increments and/or Hammond transfers. The latter transfers are like the Pigou–Dalton ones, but without the requirement that the amount transferred be fixed. The second criterion is the unanimity of all comparisons of the distributions performed by a class of additively separable social evaluation functions. The third criterion is a new statistical test based on a weighted recursion of the cumulative distribution. We also identify an exact test for the possibility of going from one distribution to another by a finite sequence of Hammond transfers only. An illustration of the usefulness of our approach for evaluating distributions of self-reported happiness level is also provided.
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bidimensional inequalities with an Ordinal Variable
Post-Print, 2011Co-Authors: Nicolas Gravel, Patrick MoyesAbstract:The normative foundations of the comparison of distributions of a single attribute between a given number of individuals are by now well-established. They originate in the equivalence between four plausible answers to the question of when a distribution x can be considered normatively better than a distribution y.
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bidimensional inequalities with an Ordinal Variable
Cahiers du GREThA (2007-2019), 2008Co-Authors: Nicolas Gravel, Patrick MoyesAbstract:We investigate the normative foundations of two empirically implementable dominance criteria for comparing distributions of two attributes, where the first one is cardinal while the second is Ordinal. The criteria we consider are Atkinson and Bourguignon\'s (1982) first quasi-ordering and a generalization of Bourguignon\'s (1989) ordered poverty gap criterion. In each case we specify the restrictions to be placed on the individual utility functions, which guarantee that all utility-inequality averse welfarist ethical observers will rank the distributions under comparison in the same way as the dominance criterion. We also identify the elementary inequality reducing transformations successive applications of which permit to derive the dominating distribution from the dominated one.
Steven N Blair - One of the best experts on this subject based on the ideXlab platform.
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relations of sit up and sit and reach tests to low back pain in adults
Journal of Orthopaedic & Sports Physical Therapy, 1998Co-Authors: Allen W Jackson, James R Morrow, Patricia A Brill, Harold W Kohl, Neil F Gordon, Steven N BlairAbstract:The sit-up and sit-and-reach tests are found on nearly all youth and adult fitness tests because of the perceived relation between performance on these tests and low back pain. However, this relationship has not been well validated. Therefore, the purpose of the study was to examine the relationship between performance on these two common field tests of muscular strength and flexibility (the sit-up and the sit-and-reach tests) and self-reported low back pain (LBP). The sample included 2,747 adults with a mean age of 44.6 ± 9.8 years. The 1-minute sit-up (mean = 30.9 ± 10.6) and sit-and-reach tests (mean = 39.88 ± 10.49 cm) were administered to participants as part of a voluntary clinical health and fitness evaluation between 1980 and 1990. Participants completed a mail-back survey in 1990 on musculoskeletal health problems. Low back pain was quantified by developing an Ordinal Variable from questionnaire responses which represented a range of severity of LBP from none (0) to LBP which required medical car...
Andrea Silvestrini - One of the best experts on this subject based on the ideXlab platform.
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a regression discontinuity design for Ordinal running Variables evaluating central bank purchases of corporate bonds
arXiv: Methodology, 2019Co-Authors: Fan Li, Andrea Mercatanti, Taneli Makinen, Andrea SilvestriniAbstract:We propose a regression discontinuity design which can be employed when assignment to treatment is determined by an Ordinal Variable. The proposal first requires estimating an ordered probit model for the Ordinal running Variable. The estimated probability of being assigned to treatment is then adopted as a latent continuous running Variable and used to identify a covariate-balanced subsample around the threshold. Assuming local unconfoundedness of the treatment in the subsample, an estimate of the effect of the program is obtained by employing a weighted estimator of the average treatment effect. Three types of balancing weights---overlap weights, inverse probability weights and ATT weights---are considered. An empirical M-estimator for the variance of the weighting estimator is derived. We apply the method to evaluate the causal effect of the Corporate Sector Purchase Programme of the European Central Bank on bond spreads.
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A regression discontinuity design for categorical ordered running Variables with an application to central bank purchases of corporate bonds
2019Co-Authors: Fan Li, Andrea Mercatanti, Taneli Makinen, Andrea SilvestriniAbstract:We propose a regression discontinuity design which can be employed when assignment to a treatment is determined by an Ordinal Variable. The proposal first requires an ordered probit model for the Ordinal running Variable to be estimated. The estimated probability of being assigned to a treatment is then adopted as a latent continuous running Variable and used to identify a covariate-balanced subsample around the threshold. Assuming the local unconfoundedness of the treatment in the subsample, an estimate of the effect of the programme is obtained by employing a weighted estimator of the average treatment effect. We apply our methodology to estimate the causal effect of the corporate sector purchase programme of the European Central Bank on bond spreads.
U Cillo - One of the best experts on this subject based on the ideXlab platform.
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is resectable hepatocellular carcinoma a contraindication to liver transplantation a novel decision model based on number of patients needed to transplant as measure of transplant benefit
Journal of Hepatology, 2014Co-Authors: Alessandro Vitale, Alessandro Cucchetti, G L Qiao, Matteo Cescon, Rafael Morales, Anna Chiara Frigo, Yong Xia, Francesco Tuci, Feng Shen, U CilloAbstract:Background & Aims Number-needed-to-treat is used in assessing the effectiveness of a health-care intervention, and reports the number of patients who need to be treated to prevent one additional bad outcome. Although largely used in medical literature, there are no studies measuring the benefit of liver transplantation (LT) over hepatic resection (HR) for hepatocellular carcinoma (HCC) in terms of "Number of patients needed to transplant (NTT)." Methods Exclusion criteria: Child-Turcotte-Pugh (CTP) Classes B–C, very large (>10cm) and multi-nodular (>2 nodules) tumours, macroscopic vascular invasion and extra-hepatic metastases. Study population: 1028 HCC cirrhotic patients from one Eastern (n=441) and two Western (n=587) surgical units. Patient survival observed after HR by proportional hazard regression model was compared to that predicted after LT by the Metroticket calculator. The benefit obtainable from LT compared to resection was analysed in relationship with number of nodules (modelled as Ordinal Variable: single vs. oligonodular), size of largest nodule (modelled as a continuous Variable), presence of microscopic vascular invasion (MVI), and time horizon from surgery (5-year vs. 10-year). Results 330 patients were beyond the Milan criteria (32%) and 597 (58%) had MVI. The prevalence of MVI was 52% in patients within Milan criteria and 71% in those beyond ( p 3cm (beyond conventional LT criteria) when MVI was absent. The 10-year scenario increased drastically the transplant benefit in all subgroups of resectable patients, and LT became an effective therapy (NTT Conclusions Based on NTT analysis, the adopted time horizon (5-year vs. 10-year scenario) is the main factor influencing the benefit of LT in patients with resectable HCC and Child A cirrhosis.
Nicolas Gravel - One of the best experts on this subject based on the ideXlab platform.
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Ranking distributions of an Ordinal Variable
Economic Theory, 2020Co-Authors: Nicolas Gravel, Brice Magdalou, Patrick MoyesAbstract:We establish an equivalence between three criteria for comparing distributions of an Ordinal Variable taking finitely many values. The first criterion is the possibility of going from one distribution to the other by a finite sequence of increments and/or Hammond transfers. The latter transfers are like the Pigou–Dalton ones, but without the requirement that the amount transferred be fixed. The second criterion is the unanimity of all comparisons of the distributions performed by a class of additively separable social evaluation functions. The third criterion is a new statistical test based on a weighted recursion of the cumulative distribution. We also identify an exact test for the possibility of going from one distribution to another by a finite sequence of Hammond transfers only. An illustration of the usefulness of our approach for evaluating distributions of self-reported happiness level is also provided.
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bidimensional inequalities with an Ordinal Variable
Post-Print, 2011Co-Authors: Nicolas Gravel, Patrick MoyesAbstract:The normative foundations of the comparison of distributions of a single attribute between a given number of individuals are by now well-established. They originate in the equivalence between four plausible answers to the question of when a distribution x can be considered normatively better than a distribution y.
-
bidimensional inequalities with an Ordinal Variable
Cahiers du GREThA (2007-2019), 2008Co-Authors: Nicolas Gravel, Patrick MoyesAbstract:We investigate the normative foundations of two empirically implementable dominance criteria for comparing distributions of two attributes, where the first one is cardinal while the second is Ordinal. The criteria we consider are Atkinson and Bourguignon\'s (1982) first quasi-ordering and a generalization of Bourguignon\'s (1989) ordered poverty gap criterion. In each case we specify the restrictions to be placed on the individual utility functions, which guarantee that all utility-inequality averse welfarist ethical observers will rank the distributions under comparison in the same way as the dominance criterion. We also identify the elementary inequality reducing transformations successive applications of which permit to derive the dominating distribution from the dominated one.