When it comes to evaluating the effectiveness of interventions, the random experiment is considered the ＂gold standard＂. Randomization is considered the gold standard because it provides a way of decreasing the chan...When it comes to evaluating the effectiveness of interventions, the random experiment is considered the ＂gold standard＂. Randomization is considered the gold standard because it provides a way of decreasing the chance that systematic differences, other than type of intervention, will be obtained between treatment and control groups. What has received little attention in the literature, however, is the fact that even with random assignment researchers may end up facing problems similar to those faced with data from a study that did not use randomization. This is because attrition may result in the values of potentially confounding variables no longer being ＂balanced＂ between （or among） the groups under investigation. This means that in order to estimate the effect of the treatment, one must find some way of adjusting for these potential confounders. Although multiple regression modeling is the way social science researchers typically control for the effects of potentially confounding variables, this paper argues that a modification of multiple regression modeling that uses propensity scores, under some conditions, may provide more parsimonious and better fitting models.展开更多
In this paper the influence of the differently distributed phase-randontized to the data obtained in dynamic analysis for critical value is studied.The calculation results validate that the sufficient phase-randomized...In this paper the influence of the differently distributed phase-randontized to the data obtained in dynamic analysis for critical value is studied.The calculation results validate that the sufficient phase-randomized of the different distributed random numbers are less influential on the critical value . This offers the theoretical foundation of the feasibility and practicality of the phase-randomized method.展开更多
Many digital platforms have employed free-content promotion strategies to deal with the high uncertainty levels regarding digital content products.However,the diversity of digital content products and user heterogenei...Many digital platforms have employed free-content promotion strategies to deal with the high uncertainty levels regarding digital content products.However,the diversity of digital content products and user heterogeneity in content preference may blur the impact of platform promotions across users and products.Therefore,free-content promotion strategies should be adapted to allocate marketing resources optimally and increase revenue.This study develops personal-ized free-content promotion strategies based on individual-level heterogeneous treatment effects and explores the causes of their heterogeneity,focusing on the moderating effect of user engagement-related variables.To this end,we utilize ran-dom field experimental data provided by a top Chinese e-book platform.We employ a framework that combines machine learning with econometric causal inference methods to estimate individual treatment effects and analyze their potential mechanisms.The analysis shows that,on average,free-content promotions lead to a significant increase in consumer pay-ments.However,the higher the level of user engagement,the lower the payment lift caused by promotions,as more-engaged users are more strongly affected by the cannibalization effect of free-content promotion.This study introduces a novel causal research design to help platforms improve their marketing strategies.展开更多
This paper examines the impacts of information about COVID-19 on pig farmers'production willingness by using endorsement experiments and follow-up surveys conducted in 2020 and 2021 in China.Our results show that,...This paper examines the impacts of information about COVID-19 on pig farmers'production willingness by using endorsement experiments and follow-up surveys conducted in 2020 and 2021 in China.Our results show that,first,farmers were less willing to scale up production when they received information about COVID-19.The information in 2020 that the second wave of COVID-19 might occur without a vaccine reduced farmers'willingness to scale up by 13.4%,while the information in 2021 that COVID-19 might continue to spread despite the introduction of vaccine reduced farmers'willingness by 4.4%.Second,farmers whose production was affected by COVID-19 were considerably less willing to scale up,given the access to COVID-19 information.Third,farmers'production willingness can predict their actual production behavior.展开更多
目的:分析近10年中医药治疗冠状动脉血运重建术后心绞痛的随机对照试验(RCT)结局指标的选择现状,为后续相关研究提供依据和基础。方法:通过系统检索中国知网(CNKI)、万方(Wanfang)、维普(VIP)、中国生物医学文献数据库(SinoMed)、PubMed...目的:分析近10年中医药治疗冠状动脉血运重建术后心绞痛的随机对照试验(RCT)结局指标的选择现状,为后续相关研究提供依据和基础。方法:通过系统检索中国知网(CNKI)、万方(Wanfang)、维普(VIP)、中国生物医学文献数据库(SinoMed)、PubMed、EMbase、Cochrane Library、Web of Science,搜集中医药治疗冠状动脉血运重建术后心绞痛的RCT。检索时限为2012年1月1日至2022年6月30日,筛选文献后提取资料,利用Cochrane偏倚风险评估工具对纳入研究进行质量评价,描述性分析结局指标的使用情况。结果:初步检索出1416篇文献,最终纳入55篇文献,包括3篇英文文献。涉及的84种结局指标主要分为9大类:生化指标(45.15%,205/454)、心绞痛疗效指标(13.88%,63/454)、安全性指标(8.15%,37/454)、临床有效率指标(7.93%,36/454)、中医证候疗效指标(7.49%,34/454)、生活质量量表(5.51%,25/454)、心电图指标(5.29%,24/454)、心功能指标(4.41%,20/454)、其他指标(2.20%,10/454)。结论:中医药治疗冠状动脉血运重建术后心绞痛的RCT结局指标遴选存在较多问题,应构建中医药治疗冠状动脉血运重建术后心绞痛的核心结局指标集,提高RCT质量。展开更多
文摘When it comes to evaluating the effectiveness of interventions, the random experiment is considered the ＂gold standard＂. Randomization is considered the gold standard because it provides a way of decreasing the chance that systematic differences, other than type of intervention, will be obtained between treatment and control groups. What has received little attention in the literature, however, is the fact that even with random assignment researchers may end up facing problems similar to those faced with data from a study that did not use randomization. This is because attrition may result in the values of potentially confounding variables no longer being ＂balanced＂ between （or among） the groups under investigation. This means that in order to estimate the effect of the treatment, one must find some way of adjusting for these potential confounders. Although multiple regression modeling is the way social science researchers typically control for the effects of potentially confounding variables, this paper argues that a modification of multiple regression modeling that uses propensity scores, under some conditions, may provide more parsimonious and better fitting models.
文摘In this paper the influence of the differently distributed phase-randontized to the data obtained in dynamic analysis for critical value is studied.The calculation results validate that the sufficient phase-randomized of the different distributed random numbers are less influential on the critical value . This offers the theoretical foundation of the feasibility and practicality of the phase-randomized method.
基金supported by the Anhui Postdoctoral Scientific Research Program Foundation(2022B579).
文摘Many digital platforms have employed free-content promotion strategies to deal with the high uncertainty levels regarding digital content products.However,the diversity of digital content products and user heterogeneity in content preference may blur the impact of platform promotions across users and products.Therefore,free-content promotion strategies should be adapted to allocate marketing resources optimally and increase revenue.This study develops personal-ized free-content promotion strategies based on individual-level heterogeneous treatment effects and explores the causes of their heterogeneity,focusing on the moderating effect of user engagement-related variables.To this end,we utilize ran-dom field experimental data provided by a top Chinese e-book platform.We employ a framework that combines machine learning with econometric causal inference methods to estimate individual treatment effects and analyze their potential mechanisms.The analysis shows that,on average,free-content promotions lead to a significant increase in consumer pay-ments.However,the higher the level of user engagement,the lower the payment lift caused by promotions,as more-engaged users are more strongly affected by the cannibalization effect of free-content promotion.This study introduces a novel causal research design to help platforms improve their marketing strategies.
基金supported by the National Social Science Fund of China(23&ZD045)the Humanities and Social Sciences Youth Foundation of the Ministry of Education of China(21YJC790087)+1 种基金the Center for Social Welfare and Public Governance of Zhejiang University,Chinathe Fundamental Research Funds for the Central Universities,China。
文摘This paper examines the impacts of information about COVID-19 on pig farmers'production willingness by using endorsement experiments and follow-up surveys conducted in 2020 and 2021 in China.Our results show that,first,farmers were less willing to scale up production when they received information about COVID-19.The information in 2020 that the second wave of COVID-19 might occur without a vaccine reduced farmers'willingness to scale up by 13.4%,while the information in 2021 that COVID-19 might continue to spread despite the introduction of vaccine reduced farmers'willingness by 4.4%.Second,farmers whose production was affected by COVID-19 were considerably less willing to scale up,given the access to COVID-19 information.Third,farmers'production willingness can predict their actual production behavior.
文摘目的:分析近10年中医药治疗冠状动脉血运重建术后心绞痛的随机对照试验(RCT)结局指标的选择现状,为后续相关研究提供依据和基础。方法:通过系统检索中国知网(CNKI)、万方(Wanfang)、维普(VIP)、中国生物医学文献数据库(SinoMed)、PubMed、EMbase、Cochrane Library、Web of Science,搜集中医药治疗冠状动脉血运重建术后心绞痛的RCT。检索时限为2012年1月1日至2022年6月30日,筛选文献后提取资料,利用Cochrane偏倚风险评估工具对纳入研究进行质量评价,描述性分析结局指标的使用情况。结果:初步检索出1416篇文献,最终纳入55篇文献,包括3篇英文文献。涉及的84种结局指标主要分为9大类:生化指标(45.15%,205/454)、心绞痛疗效指标(13.88%,63/454)、安全性指标(8.15%,37/454)、临床有效率指标(7.93%,36/454)、中医证候疗效指标(7.49%,34/454)、生活质量量表(5.51%,25/454)、心电图指标(5.29%,24/454)、心功能指标(4.41%,20/454)、其他指标(2.20%,10/454)。结论:中医药治疗冠状动脉血运重建术后心绞痛的RCT结局指标遴选存在较多问题,应构建中医药治疗冠状动脉血运重建术后心绞痛的核心结局指标集,提高RCT质量。
