本文在双重差分模型下提出一种新的协变量平衡法估计倾向得分,进而估计受处理者的平均处理效应(The Average Treatment Effect on the Treated,ATT),该方法使控制组协变量逼近基的加权样本均值等于总体协变量逼近基的样本均值。相比于...本文在双重差分模型下提出一种新的协变量平衡法估计倾向得分,进而估计受处理者的平均处理效应(The Average Treatment Effect on the Treated,ATT),该方法使控制组协变量逼近基的加权样本均值等于总体协变量逼近基的样本均值。相比于传统估计方法,本文提出的方法有如下优势,一是,能够有效减少极端估计权重的出现,进而提升目标参数估计量的准确性和稳定性;二是,无需对倾向得分做任何函数形式假定,从而可以有效避免模型误设,且所得ATT估计量的权重自动满足归一化条件;三是,最优化函数满足严凸性且不带任何约束,从而确保解的唯一性和求解简便性。在某些正则条件下,本文证明ATT估计量具有一致性与渐近正态性,并且渐近方差可达到半参数效率的下界。此外,进一步使用蒙特卡罗模拟考察估计方法的有限样本性质,结果表明该方法具有较高的估计精度。最后,基于中国家庭追踪调查数据进行实证分析,进一步验证了精准扶贫政策的有效性。展开更多
Objective:Near vision loss(NVL)is one of the leading causes of visual impairment worldwide,exerting a profound impact on individual quality of life and socio-economic development.This study aims to analyze the burden ...Objective:Near vision loss(NVL)is one of the leading causes of visual impairment worldwide,exerting a profound impact on individual quality of life and socio-economic development.This study aims to analyze the burden of NVL in China by sex and age groups from 1990 to 2021 and to project trends over the next 15 years.Methods:Using data from the Global Burden of Disease(GBD)2021 database,we conducted descriptive analyses of NVL prevalence in China,calculated age-standardized prevalence rates(ASPR)and age-standardized disability-adjusted life years rates(ASDR)to compare burden differences between sexes and age groups,and applied an autoregressive integrated moving average(ARIMA)model to predict NVL trends for the next 15 years.The model selection was based on best-fit criteria to ensure reliable projections.Results:From 1990 to 2021,China’s ASPR of NVL rose from 10096.24/100000 to 15624.54/100000,and ASDR increased from 101.75/100000 to 158.75/100000.In 2021,ASPR(16551.70/100000)and ASDR(167.69/100000)were higher among females than males(14686.21/100000 and 149.76/100000,respectively).China ranked highest globally in both NVL cases and disability-adjusted life years(DALYs),with female burden significantly exceeding male burden.Projections indicated this trend and sex gap will persist until 2036.Compared with 1990,the prevalence cases and DALYs increased by 239.20%and 238.82%,respectively in 2021,with the highest burden among females and the 55−59 age group.The ARIMA model predicted continued increases in prevalence and DALYs by 2036,with females maintaining a higher burden than males.Conclusion:This study reveals a marked increase in the NVL burden in China and predicts continued growth in the coming years.Public health policies should prioritize NVL prevention and control,with special attention to women and middle-aged populations to mitigate long-term societal and health impacts.展开更多
文摘本文在双重差分模型下提出一种新的协变量平衡法估计倾向得分,进而估计受处理者的平均处理效应(The Average Treatment Effect on the Treated,ATT),该方法使控制组协变量逼近基的加权样本均值等于总体协变量逼近基的样本均值。相比于传统估计方法,本文提出的方法有如下优势,一是,能够有效减少极端估计权重的出现,进而提升目标参数估计量的准确性和稳定性;二是,无需对倾向得分做任何函数形式假定,从而可以有效避免模型误设,且所得ATT估计量的权重自动满足归一化条件;三是,最优化函数满足严凸性且不带任何约束,从而确保解的唯一性和求解简便性。在某些正则条件下,本文证明ATT估计量具有一致性与渐近正态性,并且渐近方差可达到半参数效率的下界。此外,进一步使用蒙特卡罗模拟考察估计方法的有限样本性质,结果表明该方法具有较高的估计精度。最后,基于中国家庭追踪调查数据进行实证分析,进一步验证了精准扶贫政策的有效性。
基金supported by the Natural Science Foundation of Hunan Province(2023JJ30817)Hunan Provincial Natural Science Foundation-Hengyang City Joint Fund Project(2025JJ70129)+1 种基金Changsha Natural Science Foundation(kq2403057)China。
文摘Objective:Near vision loss(NVL)is one of the leading causes of visual impairment worldwide,exerting a profound impact on individual quality of life and socio-economic development.This study aims to analyze the burden of NVL in China by sex and age groups from 1990 to 2021 and to project trends over the next 15 years.Methods:Using data from the Global Burden of Disease(GBD)2021 database,we conducted descriptive analyses of NVL prevalence in China,calculated age-standardized prevalence rates(ASPR)and age-standardized disability-adjusted life years rates(ASDR)to compare burden differences between sexes and age groups,and applied an autoregressive integrated moving average(ARIMA)model to predict NVL trends for the next 15 years.The model selection was based on best-fit criteria to ensure reliable projections.Results:From 1990 to 2021,China’s ASPR of NVL rose from 10096.24/100000 to 15624.54/100000,and ASDR increased from 101.75/100000 to 158.75/100000.In 2021,ASPR(16551.70/100000)and ASDR(167.69/100000)were higher among females than males(14686.21/100000 and 149.76/100000,respectively).China ranked highest globally in both NVL cases and disability-adjusted life years(DALYs),with female burden significantly exceeding male burden.Projections indicated this trend and sex gap will persist until 2036.Compared with 1990,the prevalence cases and DALYs increased by 239.20%and 238.82%,respectively in 2021,with the highest burden among females and the 55−59 age group.The ARIMA model predicted continued increases in prevalence and DALYs by 2036,with females maintaining a higher burden than males.Conclusion:This study reveals a marked increase in the NVL burden in China and predicts continued growth in the coming years.Public health policies should prioritize NVL prevention and control,with special attention to women and middle-aged populations to mitigate long-term societal and health impacts.
