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作者：Kang, Hyunseung; Zhang, Anru; Cai, T. Tony; Small, Dylan S.
作者单位：University of Pennsylvania; University of Pennsylvania
摘要：Instrumental variables have been widely used for estimating the causal effect between exposure and outcome. Conventional estimation methods require complete knowledge about all the instruments' validity; a valid instrument must not have a direct effect on the outcome and not be related to unmeasured confounders. Often, this is impractical as highlighted by Mendelian randomization studies where genetic markers are used as instruments and complete knowledge about instruments' validity is equival...
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作者：Gaskins, J. T.; Daniels, M. J.; Marcus, B. H.
作者单位：University of Louisville; University of Texas System; University of Texas Austin; University of California System; University of California San Diego
摘要：Inference on data with missingness can be challenging, particularly if the knowledge that a measurement was unobserved provides information about its distribution. Our work is motivated by the Commit to Quit II study, a smoking cessation trial that measured smoking status and weight change as weekly outcomes. It is expected that dropout in this study was informative and that patients with missed measurements are more likely to be smoking, even after conditioning on their observed smoking and w...
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作者：Blocker, Alexander W.; Airoldi, Edoardo M.
作者单位：Harvard University
摘要：We consider the problem of estimating the genome-wide distribution of nucleosome positions from paired end sequencing data. We develop a modeling approach based on nonparametric templates to control for the variability along the sequence of read counts associated with nucleosomal DNA due to enzymatic digestion and other sample preparation steps, and we develop a calibrated Bayesian method to detect local concentrations of nucleosome positions. We also introduce a set of estimands that provides...
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作者：Yu, Zhou; Dong, Yuexiao; Zhu, Li-Xing
作者单位：Beijing Normal University; Hong Kong Baptist University
摘要：We propose trace pursuit for model-free variable selection under the sufficient dimension-reduction paradigm. Two distinct algorithms are proposed: stepwise trace pursuit and forward trace pursuit. Stepwise trace pursuit achieves selection consistency with fixed p. Forward trace pursuit can serve as an initial screening step to speed up the computation in the case of ultrahigh dimensionality. The screening, consistency property of forward trace pursuit based on sliced inverse regression is est...
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作者：Ding, Peng; Dasgupta, Tirthankar
作者单位：Harvard University
摘要：Causal inference in completely randomized treatment-control studies with binary outcomes is discussed from Fisherian, Neymanian, and Bayesian perspectives, using the potential outcomes model. A randomization-based justification of Fisher's exact test is provided. Arguing that the crucial assumption of constant causal effect is often unrealistic, and holds only for extreme cases, some new asymptotic and Bayesian inferential procedures are proposed. The proposed procedures exploit the intrinsic ...
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作者：Taddy, Matt
作者单位：Microsoft; University of Chicago
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作者：Louis, Thomas A.; Keiding, Niels
作者单位：Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health; University of Copenhagen
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作者：Jing, Bing-Yi; Li, Zhouping; Pan, Guangming; Zhou, Wang
作者单位：Hong Kong University of Science & Technology; Lanzhou University; Nanyang Technological University; National University of Singapore
摘要：The article is concerned with empirical Bayes shrinkage estimators for the heteroscedastic hierarchical normal model using Stein's unbiased estimate of risk (SURE). Recently, Xie, Kou, and Brown proposed. a class of estimators for this type of problems and established their asymptotic optimality properties under the assumption of known but unequal variances. In this article, we consider this problem with unequal and unknown variances, which may be more appropriate in real situations. By placin...
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作者：Lockwood, J. R.; McCaffrey, Daniel F.
作者单位：Educational Testing Service (ETS)
摘要：Matching estimators are commonly used to estimate causal effects in nonexperimental settings. Covariate measurement error can be problematic for matching estimators when observational treatment groups differ on latent quantities observed only through error-prone surrogates. We establish necessary and sufficient conditions for matching and weighting with functions of observed covariates to yield unconfounded causal effect estimators, generalizing results from the standard (i.e., no measurement ...
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作者：Robbins, Michael W.; Gallagher, Colin M.; Lund, Robert B.
作者单位：RAND Corporation
摘要：This article develops a test for a single changepoint in a general setting that allows for correlated time series regression errors, a seasonal cycle, time-varying regression factors, and covariate information. Within, a changepoint statistic is constructed from likelihood ratio principles and its asymptotic distribution is derived. The asymptotic distribution of the changepoint statistic is shown to be invariant of the seasonal cycle and the covariates should the latter obey some simple limit...
