Pub Date : 2023-12-15DOI: 10.1080/24754269.2023.2293554
Lu Wang, Peisong Han
{"title":"Multiply robust estimation for average treatment effect among treated","authors":"Lu Wang, Peisong Han","doi":"10.1080/24754269.2023.2293554","DOIUrl":"https://doi.org/10.1080/24754269.2023.2293554","url":null,"abstract":"","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139000997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-30DOI: 10.1080/24754269.2023.2263721
Ran Wan, Yang Bai
{"title":"Communication-efficient distributed statistical inference on zero-inflated Poisson models","authors":"Ran Wan, Yang Bai","doi":"10.1080/24754269.2023.2263721","DOIUrl":"https://doi.org/10.1080/24754269.2023.2263721","url":null,"abstract":"","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136104041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-27DOI: 10.1080/24754269.2023.2272554
Fang Fang, Shenliao Bao
{"title":"FragmGAN: generative adversarial nets for fragmentary data imputation and prediction","authors":"Fang Fang, Shenliao Bao","doi":"10.1080/24754269.2023.2272554","DOIUrl":"https://doi.org/10.1080/24754269.2023.2272554","url":null,"abstract":"","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136316718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-05DOI: 10.1080/24754269.2023.2263720
Ting Ye, Jun Shao, Yanyao Yi
In randomized clinical trials with right-censored time-to-event outcomes, the popular log-rank test without adjusting for baseline covariates is asymptotically valid for treatment effect under simple randomization of treatments but is too conservative under covariate-adaptive randomization. The stratified log-rank test, which adjusts baseline covariates in the test procedure by stratification, is asymptotically valid regardless of what treatment randomization is applied. In the literature, however, under simple randomization there is no affirmative conclusion about whether the stratified log-rank test is asymptotically more powerful than the unstratified log-rank test. In this article we show when the stratified and unstratified log-rank tests aim for the same null hypothesis and that, under simple randomization, the stratified log-rank test is asymptotically more powerful than the unstratified log-rank test in the region of alternative hypothesis that is specified by a Cox proportional hazards model. We also provide some discussion about why we do not have an affirmative conclusion in general.
{"title":"Log-rank and stratified log-rank tests","authors":"Ting Ye, Jun Shao, Yanyao Yi","doi":"10.1080/24754269.2023.2263720","DOIUrl":"https://doi.org/10.1080/24754269.2023.2263720","url":null,"abstract":"In randomized clinical trials with right-censored time-to-event outcomes, the popular log-rank test without adjusting for baseline covariates is asymptotically valid for treatment effect under simple randomization of treatments but is too conservative under covariate-adaptive randomization. The stratified log-rank test, which adjusts baseline covariates in the test procedure by stratification, is asymptotically valid regardless of what treatment randomization is applied. In the literature, however, under simple randomization there is no affirmative conclusion about whether the stratified log-rank test is asymptotically more powerful than the unstratified log-rank test. In this article we show when the stratified and unstratified log-rank tests aim for the same null hypothesis and that, under simple randomization, the stratified log-rank test is asymptotically more powerful than the unstratified log-rank test in the region of alternative hypothesis that is specified by a Cox proportional hazards model. We also provide some discussion about why we do not have an affirmative conclusion in general.","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134975302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-04DOI: 10.1080/24754269.2023.2262360
Shujin Wu, Ping Bi
In the paper, the autoregressive moving average model for matrix time series (MARMA) is investigated. The properties of the MARMA model are investigated by using the conditional least square estimation, the conditional maximum likelihood estimation, the projection theorem in Hilbert space and the decomposition technique of time series, which include necessary and sufficient conditions for stationarity and invertibility, model parameter estimation, model testing and model forecasting.
{"title":"Autoregressive moving average model for matrix time series","authors":"Shujin Wu, Ping Bi","doi":"10.1080/24754269.2023.2262360","DOIUrl":"https://doi.org/10.1080/24754269.2023.2262360","url":null,"abstract":"In the paper, the autoregressive moving average model for matrix time series (MARMA) is investigated. The properties of the MARMA model are investigated by using the conditional least square estimation, the conditional maximum likelihood estimation, the projection theorem in Hilbert space and the decomposition technique of time series, which include necessary and sufficient conditions for stationarity and invertibility, model parameter estimation, model testing and model forecasting.","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135644638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-26DOI: 10.1080/24754269.2023.2261351
Siyi Liu, Yilong Zhang, Gregory T. Golm, Guanghan (Frank) Liu, Shu Yang
Missing data is unavoidable in longitudinal clinical trials, and outcomes are not always normally distributed. In the presence of outliers or heavy-tailed distributions, the conventional multiple imputation with the mixed model with repeated measures analysis of the average treatment effect (ATE) based on the multivariate normal assumption may produce bias and power loss. Control-based imputation (CBI) is an approach for evaluating the treatment effect under the assumption that participants in both the test and control groups with missing outcome data have a similar outcome profile as those with an identical history in the control group. We develop a robust framework to handle non-normal outcomes under CBI without imposing any parametric modeling assumptions. Under the proposed framework, sequential weighted robust regressions are applied to protect the constructed imputation model against non-normality in the covariates and the response variables. Accompanied by the subsequent mean imputation and robust model analysis, the resulting ATE estimator has good theoretical properties in terms of consistency and asymptotic normality. Moreover, our proposed method guarantees the analysis model robustness of the ATE estimation in the sense that its asymptotic results remain intact even when the analysis model is misspecified. The superiority of the proposed robust method is demonstrated by comprehensive simulation studies and an AIDS clinical trial data application.
{"title":"Robust analyzes for longitudinal clinical trials with missing and non-normal continuous outcomes","authors":"Siyi Liu, Yilong Zhang, Gregory T. Golm, Guanghan (Frank) Liu, Shu Yang","doi":"10.1080/24754269.2023.2261351","DOIUrl":"https://doi.org/10.1080/24754269.2023.2261351","url":null,"abstract":"Missing data is unavoidable in longitudinal clinical trials, and outcomes are not always normally distributed. In the presence of outliers or heavy-tailed distributions, the conventional multiple imputation with the mixed model with repeated measures analysis of the average treatment effect (ATE) based on the multivariate normal assumption may produce bias and power loss. Control-based imputation (CBI) is an approach for evaluating the treatment effect under the assumption that participants in both the test and control groups with missing outcome data have a similar outcome profile as those with an identical history in the control group. We develop a robust framework to handle non-normal outcomes under CBI without imposing any parametric modeling assumptions. Under the proposed framework, sequential weighted robust regressions are applied to protect the constructed imputation model against non-normality in the covariates and the response variables. Accompanied by the subsequent mean imputation and robust model analysis, the resulting ATE estimator has good theoretical properties in terms of consistency and asymptotic normality. Moreover, our proposed method guarantees the analysis model robustness of the ATE estimation in the sense that its asymptotic results remain intact even when the analysis model is misspecified. The superiority of the proposed robust method is demonstrated by comprehensive simulation studies and an AIDS clinical trial data application.","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"300 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134886547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-26DOI: 10.1080/24754269.2023.2260046
Tingting Luo, Benchong Li
Sample compression schemes were first proposed by Littlestone and Warmuth in 1986. Undirected graphical model is a powerful tool for classification in statistical learning. In this paper, we consider labelled compression schemes for concept classes induced by discrete undirected graphical models. For the undirected graph of two vertices with no edge, where one vertex takes two values and the other vertex can take any finite number of values, we propose an algorithm to establish a labelled compression scheme of size VC dimension of associated concept class. Further, we extend the result to other two types of undirected graphical models and show the existence of labelled compression schemes of size VC dimension for induced concept classes. The work of this paper makes a step forward in solving sample compression problem for concept class induced by a general discrete undirected graphical model.
{"title":"Compression schemes for concept classes induced by three types of discrete undirected graphical models","authors":"Tingting Luo, Benchong Li","doi":"10.1080/24754269.2023.2260046","DOIUrl":"https://doi.org/10.1080/24754269.2023.2260046","url":null,"abstract":"Sample compression schemes were first proposed by Littlestone and Warmuth in 1986. Undirected graphical model is a powerful tool for classification in statistical learning. In this paper, we consider labelled compression schemes for concept classes induced by discrete undirected graphical models. For the undirected graph of two vertices with no edge, where one vertex takes two values and the other vertex can take any finite number of values, we propose an algorithm to establish a labelled compression scheme of size VC dimension of associated concept class. Further, we extend the result to other two types of undirected graphical models and show the existence of labelled compression schemes of size VC dimension for induced concept classes. The work of this paper makes a step forward in solving sample compression problem for concept class induced by a general discrete undirected graphical model.","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134960861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.1080/24754269.2023.2250237
Ming-Chung Chang
{"title":"Bayesian-inspired minimum contamination designs under a double-pair conditional effect model","authors":"Ming-Chung Chang","doi":"10.1080/24754269.2023.2250237","DOIUrl":"https://doi.org/10.1080/24754269.2023.2250237","url":null,"abstract":"","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43462438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-06DOI: 10.1080/24754269.2023.2238975
Wanling Zhou, Sulin Pang, Zhiliang He
{"title":"The study on systemic risk of rural finance based on macro–micro big data and machine learning","authors":"Wanling Zhou, Sulin Pang, Zhiliang He","doi":"10.1080/24754269.2023.2238975","DOIUrl":"https://doi.org/10.1080/24754269.2023.2238975","url":null,"abstract":"","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46406432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.1080/24754269.2023.2189348
W. Guo, Jianan Hui, Bob Zhong
{"title":"Single-arm phase II three-outcome designs with handling of over-running/under-running","authors":"W. Guo, Jianan Hui, Bob Zhong","doi":"10.1080/24754269.2023.2189348","DOIUrl":"https://doi.org/10.1080/24754269.2023.2189348","url":null,"abstract":"","PeriodicalId":22070,"journal":{"name":"Statistical Theory and Related Fields","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44000276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}