Sample size re‐estimation incorporating prior information on a nuisance parameter

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.     

The effect of media sexism on women’s political ambition: evidence from a worldwide study

This paper presents results from one of the first global studies on the relationship between media sexism and the share of candidates for the lower chamber of national parliaments who are women. Data on media sexism come from the Global Media Monitoring Project, the most reliable worldwide source for media coverage from a gender perspective. The data on share of female political candidates come from the Inter-Parliamentary Union. The results show that that there is, even when controlling for the number of women in parliament, electoral system, gender quotas, level of human development, level of women’s rights, freedom from corruption, and media access, a significant relationship between media sexism—measured as (i) the share of all news subjects that are women and (ii) the share of all news subjects portrayed in the function of experts who are women—and the share of women candidates for parliament: the higher the level of media sexism, the lower the share of women candidates. The theory discussed zooms in on a bystander effect: We hypothesize that sexist portrayals of women in the media stifle ambition among women who, in a less sexist media environment, would be willing to stand as political candidates.     

Business reform outcomes: Why so different?

Post-crisis policy making increasingly focuses on doing business reforms. We argue that the effects of those reforms will be different across countries. To understand the reasons for the reform outcome divergence, we advance a novel firm-size distribution (FSDs) argument. At the center of the argument is the fact that FSDs are different across countries and stable over time. Then, if a given doing business reform induces firms of different size to grow differently, this will produce a variety of reform outcomes across countries. To advance the argument, we set up a tractable general equilibrium (GE) model and study how firms of different size grow after a doing business reform. The model predicts that larger firms will grow faster than smaller firms after the reform. The model predictions are tested on the Enterprise Surveys (ES) data, merged with the Doing Business indicators. We confirm that firms of different size grow differently after a Doing Business reform. Thus, based on the notable differences of firm size distributions across countries, identical reforms to start, operate and close a business will produce a variety of reform outcomes across countries.     

Role of Leaders as Agents of Negotiation for Counterbalancing Cultural Dissonance in the Middle East and North Africa Region

This study provides a unique perspective in the field of cross-cultural management by exploring the relationship between “cultural dissonance”—the gap between cultural values and actual practice—and effective leadership attributes in the Middle East and North Africa (MENA) region. Incorporating cultural dissonance into implicit leadership theory, the study uses measurements of dissonance on nine cultural dimensions to identify particular leadership preferences in seven MENA countries. The overall findings suggest that societies prefer leaders who counterbalance cultural dissonance by allowing space for negotiations by members of society to reduce disparities between cultural values—“the way things should be”—and actual practices—“the way things are.” The greater the disparity between cultural values and practices, the greater the citizens' desire that leaders act as agents of change by creating space for negotiation.     

蒙台梭利儿童饮食生活教育的扎根研究

当今国内对蒙台梭利的研究更多体现在宏观层面，而专门对饮食生活教育的研究较少受到关注，特别是缺乏“深描”性质的质化研究。鉴于此，研究者以6部蒙台梭利教育论著作为“访谈”对象，采用非交互性资料收集方式，深度挖掘文献资源，通过三级编码发展出蒙氏儿童饮食生活教育的扎根理论。研究发现，蒙氏儿童饮食生活教育思想体系包括饮食营养的价值追求、食物的来源及处理、儿童饮食行为的发展、饮食生活教育过程等4个理论构念，其中包含健康功能、健康权利、健康卫生、食品制作、食物选择、饮食文化、发展需求、发展阶段、营养因素、行为练习、饮食调控、教育误区等12个触发式概念。蒙氏饮食生活教育也是一个调节儿童与食物主客交互并具有积极价值追求的实践体系，对于当今儿童健康教育现实具有极强的指导意义。     

How publics’ active and passive communicative behaviors affect their tornado responses: An integration of STOPS and SMCC

During imminent threat crises, such as natural disasters, publics have minutes to decide how to respond after receiving a warning. This study advances understanding of publics’ crisis communicative and noncommunicative behaviors in the context of tornadoes through combining and extending two theories: the social-mediated crisis communication (SMCC) model and the situational theory of problem solving (STOPS). Findings from a survey of Southeast U.S. residents (n = 1,585) indicate that STOPS is internally consistent and accurate at measuring its intended outcomes of communicative action in problem solving. However, the STOPS measures do not have a significant relationship with the desirable outcome for imminent threat crisis communication: individuals following government’s protective action guidance about tornadoes. In comparison, the expanded SMCC model predicts individuals’ self-reported compliance. Finally, variables from the SMCC model and tornado-specific variables were integrated into the STOPS model to explain individuals’ communicative engagement. Implications for theory and public relations practice are discussed.     

Resistance as Sacrifice: Toward an Ascetic Antiracism

Often described as an outcome, inequality is better understood as a social process—a function of how institutions are structured and reproduced, and the ways people act and interact within them across time. Racialized inequality persists because it is enacted moment to moment, context to context—and it can be ended should those who currently perpetuate it commit themselves to playing a different role instead. This essay makes three core contributions. First, it highlights a disturbing parity between the people who are most rhetorically committed to ending racialized inequality and those who are most responsible for its persistence. Next, it explores the origin of this paradox—how it is that ostensibly antiracist intentions are transmuted into “benevolently racist” actions. Finally, it presents an alternative approach to mitigating racialized inequality, one that more effectively challenges the self‐oriented and extractive logics undergirding systemic racism, rather than expropriating blame to others, or else adopting introspective and psychologized approaches to fundamentally social problems, those sincerely committed to antiracism can take concrete steps in the real world—actions that require no legislation or coercion of naysayers, just a willingness to personally make sacrifices for the sake of racial justice.     

Propensity score prediction for electronic healthcare databases using super learner and high-dimensional propensity score methods

ABSTRACT

The optimal learner for prediction modeling varies depending on the underlying data-generating distribution. Super Learner (SL) is a generic ensemble learning algorithm that uses cross-validation to select among a ‘library’ of candidate prediction models. While SL has been widely studied in a number of settings, it has not been thoroughly evaluated in large electronic healthcare databases that are common in pharmacoepidemiology and comparative effectiveness research. In this study, we applied and evaluated the performance of SL in its ability to predict the propensity score (PS), the conditional probability of treatment assignment given baseline covariates, using three electronic healthcare databases. We considered a library of algorithms that consisted of both nonparametric and parametric models. We also proposed a novel strategy for prediction modeling that combines SL with the high-dimensional propensity score (hdPS) variable selection algorithm. Predictive performance was assessed using three metrics: the negative log-likelihood, area under the curve (AUC), and time complexity. Results showed that the best individual algorithm, in terms of predictive performance, varied across datasets. The SL was able to adapt to the given dataset and optimize predictive performance relative to any individual learner. Combining the SL with the hdPS was the most consistent prediction method and may be promising for PS estimation and prediction modeling in electronic healthcare databases.     

网络扶贫的内涵及实践特色

借助文献研究和对比研究，在解释网络扶贫内涵的基础上，探讨了网络扶贫的实践特色。研究发现，网络扶贫能够推动扶贫思维的深层变革：从单向思维到互联网思维；助力扶贫对象的精准识别：从主观判断到科学界定；促进扶贫动力的内外融通：从外源救济到内生崛起；推进扶贫主体的系统升级：从单一分离到通力合作；优化扶贫路径的实践切入：从共性举措到个性特色；保障扶贫效果的稳定有序：从短期快速到长期持续。因此，在网络扶贫的过程中，既要注重提升网络扶贫主体的人力资本、加强农村互联网基础设施建设，又要注重构建网络扶贫信息服务体系、培育贫困地区特色产业，推进网络公益扶贫有序发展。