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951.
Prior information is often incorporated informally when planning a clinical trial. Here, we present an approach on how to incorporate prior information, such as data from historical clinical trials, into the nuisance parameter–based sample size re‐estimation in a design with an internal pilot study. We focus on trials with continuous endpoints in which the outcome variance is the nuisance parameter. For planning and analyzing the trial, frequentist methods are considered. Moreover, the external information on the variance is summarized by the Bayesian meta‐analytic‐predictive approach. To incorporate external information into the sample size re‐estimation, we propose to update the meta‐analytic‐predictive prior based on the results of the internal pilot study and to re‐estimate the sample size using an estimator from the posterior. By means of a simulation study, we compare the operating characteristics such as power and sample size distribution of the proposed procedure with the traditional sample size re‐estimation approach that uses the pooled variance estimator. The simulation study shows that, if no prior‐data conflict is present, incorporating external information into the sample size re‐estimation improves the operating characteristics compared to the traditional approach. In the case of a prior‐data conflict, that is, when the variance of the ongoing clinical trial is unequal to the prior location, the performance of the traditional sample size re‐estimation procedure is in general superior, even when the prior information is robustified. When considering to include prior information in sample size re‐estimation, the potential gains should be balanced against the risks. 相似文献
952.
Maria Sironi 《Journal of Family and Economic Issues》2018,39(1):103-116
Transition to adulthood has undoubtedly changed in the last few decades. For youth today, an important marker of adulthood is self-actualization in their professional career, and, consequently, also the achievement of stable financial conditions. Economic conditions of youth are greatly subject to fluctuations in the economy, and the subsequent governmental response. Using the Luxembourg Income Study, this work investigates the trends in income from work of young adults before and after the Great Recession of 2008 in five countries—US, UK, Norway, Germany, and Spain. The findings showed deterioration in economic conditions of young men, but with differences across countries. Young women suffered less from the crisis, and in some countries, their economic situation improved. The general negative trend was especially pronounced for those with high education, which is primarily because they stayed in education longer. 相似文献
953.
954.
Perry C. Oddo Ben S. Lee Gregory G. Garner Vivek Srikrishnan Patrick M. Reed Chris E. Forest Klaus Keller 《Risk analysis》2020,40(1):153-168
Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives. Here, we implement and improve on a classic decision-analytical model (Van Dantzig 1956) to: (i) capture tradeoffs across conflicting stakeholder objectives, (ii) demonstrate the consequences of structural uncertainties in the sea-level rise and storm surge models, and (iii) identify the parametric uncertainties that most strongly influence each objective using global sensitivity analysis. We find that the flood adaptation model produces potentially myopic solutions when formulated using traditional mean-centric decision theory. Moving from a single-objective problem formulation to one with multiobjective tradeoffs dramatically expands the decision space, and highlights the need for compromise solutions to address stakeholder preferences. We find deep structural uncertainties that have large effects on the model outcome, with the storm surge parameters accounting for the greatest impacts. Global sensitivity analysis effectively identifies important parameter interactions that local methods overlook, and that could have critical implications for flood adaptation strategies. 相似文献
955.
Antonio M. Jaime‐Castillo Ildefonso Marqus‐Perales 《The British journal of sociology》2019,70(1):138-165
The literature on preferences for redistribution has paid little attention to the effect of social mobility on the demand for redistribution and no systematic test of the hypotheses connecting social mobility and preferences for redistribution has yet been done to date. We use the diagonal reference model to estimate the effect of origin and destination classes on preferences for redistribution in a large sample of European countries using data from the European Social Survey. Our findings are consistent with the logic of acculturation in the sense that newcomers tend to adapt their views to those of the destination class at early stages and that upward and downward mobility do not have distinctive effects on the formation of political preferences. However, even though social origins seem to have a limited impact on preferences for redistribution, the evidence does not support the hypothesis that mobile and non‐mobile individuals are alike. We also find that the effect of social origin on preferences varies largely across countries. The empirical evidence leads to the conclusion that the effect of social origin on preferences for redistribution increases in contexts of strong familism. 相似文献
956.
Scholars still do not fully understand what activates cynicism in citizens. Although many expect that negative campaigning contributes to this, no consistent evidence has been found. This research introduces a new measure of appeals to cynicism that expands the commonly used positive–negative taxonomy of tone in advertising. Through a content analyses of more than 600 political advertisements aired during U.S. Senate elections, we identify the extent to which candidates use cynical appeals and the conditions under which these are used. We find that appeals to cynicism are common, are distinct from negative appeals, and that most often, ad sponsors target opponents with cynical appeals, describing them as selfish, dishonest and incompetent. Cynicism appears to be a central part of American campaign rhetoric, used by all sorts of candidates, regardless of party, in many different situations. The prevalence of appeals to cynicism may help explain rising cynicism among the public. 相似文献
957.
Holly J. Payne Jennifer Mize Smith Kimberlee K. Everson Ganer L. Newman Iv 《Atlantic journal of communication》2019,27(1):30-45
Nonprofit organizations (NPOs) achieve desired outcomes by fostering organizational identification. However, little research has explored how identification with the cause or the recipients of support relates to identification with the NPO. This study developed the Identification with Social Causes Scale as a mechanism for distinguishing organizational identification from identification with a social group or cause. Data were collected using two groups: the homeless (n = 318) and HIV positive (n = 314) individuals. Exploratory factor analysis and multigroup confirmatory factor analysis yielded a 9-item scale measuring two dimensions: attachment and consubstantiality. Initial construct validity of the scale was established. 相似文献
958.
The goal of this study was to examine child and parent predictors of children's hostile attribution bias (HAB) with a particular focus on exploring the associations between parents’ early attribution of child misbehavior and children's HAB in the transition to school age. Participants were 241 children (118 girls) of middle‐income families who were at risk for school‐age conduct problems. Multi‐method, multi‐informant data were collected on maternal attributions of child misbehavior, parental use of corporal punishment, and child attributes (i.e., verbal IQ, effortful control, theory of mind, and emotional understanding) at 3 years, and child HAB in ambiguous situations at 6 years. Results indicated that mothers’ internal explanations for children's misconduct may either reduce or increase children's later HAB depending on the specific content of attributions, such that mothers’ belief that children misbehave because of their internal state (i.e., emotional state or temperament) was associated with lower levels of child HAB, whereas attributing power‐based motives (i.e., manipulative, controlling intentions) in children was associated with higher levels of HAB. The findings are discussed with respect to appreciating the complexity of parents’ explanations for children's behavior, and considering parental cognition as a potential target for early identification and prevention of child HAB and related problems. 相似文献
959.
960.
Richard William Farebrother 《Statistical Methods and Applications》2018,27(2):363-364