-
作者：Kuipers, Jack; Moffa, Giusi
作者单位：Swiss Federal Institutes of Technology Domain; ETH Zurich; University of London; University College London
摘要：Acyclic digraphs are the underlying representation of Bayesian networks, a widely used class of probabilistic graphical models. Learning the underlying graph from data is a way of gaining insights about the structural properties of a domain. Structure learning forms one of the inference challenges of statistical graphical models. Markov chain Monte Carlo (MCMC) methods, notably structure MCMC, to sample graphs from the posterior distribution given the data are probably the only viable option f...
-
作者：Yang, Qing; Pan, Guangming
作者单位：Nanyang Technological University
摘要：This article considers testing equality of two population covariance matrices when the data dimension p diverges with the sample size n (p/n c > 0). We propose a weighted test statistic that is data-driven and powerful in both faint alternatives (many small disturbances) and sparse alternatives (several large disturbances). Its asymptotic null distribution is derived by large random matrix theory without assuming the existence of a limiting cumulative distribution function of the population co...
-
作者：Zou, Tao; Lan, Wei; Wang, Hansheng; Tsai, Chih-Ling
作者单位：Peking University; Australian National University; Southwestern University of Finance & Economics - China; Southwestern University of Finance & Economics - China; University of California System; University of California Davis
摘要：This article introduces covariance regression analysis for a p-dimensional response vector. The proposed method explores the regression relationship between the p-dimensional covariance matrix and auxiliary information. We study three types of estimators: maximum likelihood, ordinary least squares, and feasible generalized least squares estimators. Then, we demonstrate that these regression estimators are consistent and asymptotically normal. Furthermore, we obtain the high dimensional and lar...
-
作者：Egleston, Brian L.; Uzzo, Robert G.; Wong, Yu-Ning
作者单位：Fox Chase Cancer Center; Pennsylvania Commonwealth System of Higher Education (PCSHE); Temple University; Fox Chase Cancer Center; Pennsylvania Commonwealth System of Higher Education (PCSHE); Temple University; Fox Chase Cancer Center; Pennsylvania Commonwealth System of Higher Education (PCSHE); Temple University
摘要：Rates of kidney cancer have been increasing, with small incidental tumors experiencing the fastest growth rates. Much of the increase could be due to increased use of CT scans, MRIs, and ultrasounds for unrelated conditions. Many tumors might never have been detected or become symptomatic in the past. This suggests that many patients might benefit from less aggressive therapy, such as active surveillance by which tumors are surgically removed only if they become sufficiently large. However, it...
-
作者：Garg, Vikram V.; Stogner, Roy H.
作者单位：Massachusetts Institute of Technology (MIT); University of Texas System; University of Texas Austin
摘要：Latin hypercube sampling (LHS) is a robust, scalable Monte Carlo method that is used in many areas of science and engineering. We present a new algorithm for generating hierarchic Latin hypercube sets (HLHS) that are recursively divisible into LHS subsets. Based on this new construction, we introduce a hierarchical incremental LHS (HILHS) method that allows the user to employ LHS in a flexibly incremental setting. This overcomes a drawback of many LHS schemes that require the entire sample set...
-
作者：Fogarty, Colin B.; Shi, Pixu; Mikkelsen, Mark E.; Small, Dylan S.
作者单位：Massachusetts Institute of Technology (MIT); University of Pennsylvania; University of Pennsylvania; University of Pennsylvania
摘要：We present methods for conducting hypothesis testing and sensitivity analyses for composite null hypotheses in matched observational studies when outcomes are binary. Causal estimands discussed include the causal risk difference, causal risk ratio, and the effect ratio. We show that inference under the assumption of no unmeasured confounding can be performed by solving an integer linear program, while inference allowing for unmeasured confounding of a given strength requires solving an integer...
-
作者：Ma, Shujie; Huang, Jian
作者单位：University of California System; University of California Riverside; University of Iowa
摘要：An important step in developing individualized treatment strategies is correct identification of subgroups of a heterogeneous population to allow specific treatment for each subgroup. This article considers the problem using samples drawn from a population consisting of subgroups with different mean values, along with certain covariates. We propose a penalized approach for subgroup analysis based on a regression model, in which heterogeneity is driven by unobserved latent factors and thus can ...
-
作者：Manrique-Vallier, Daniel; Reiter, Jerome P.
作者单位：Indiana University System; Indiana University Bloomington; Duke University
摘要：In categorical data, it is typically the case that some combinations of variables are theoretically impossible, such as a 3-year-old child who is married or a man who is pregnant. In practice, however, reported values often include such structural zeros due to, for example, respondent mistakes or data processing errors. To purge data of such errors, many statistical organizations use a process known as edit-imputation. The basic idea is first to select reported values to change according to so...
-
作者：Miles, Caleb H.; Shpitser, Ilya; Kanki, Phyllis; Meloni, Seema; Tchetgen, Eric J. Tchetgen
作者单位：University of California System; University of California Berkeley; Johns Hopkins University; Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard T.H. Chan School of Public Health
摘要：Since the early 2000s, evidence has accumulated for a significant differential effect of first-line antiretroviral therapy (ART) regimens on human immunodeficiency virus (HIV) viral load suppression. This finding was replicated in our data from the Harvard President's Emergency Plan for AIDS Relief (PEPFAR) program in Nigeria. Investigators were interested in finding the source of these differences, that is, understanding the mechanisms through which one regimen outperforms another, particular...
-
作者：Richardson, Thomas S.; Robins, James M.; Wang, Linbo
作者单位：University of Washington; University of Washington Seattle; Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard T.H. Chan School of Public Health; University of Washington; University of Washington Seattle
摘要：A common problem in formulating models for the relative risk and risk difference is the variation dependence between these parameters and the baseline risk, which is a nuisance model. We address this problem by proposing the conditional log odds-product as a preferred nuisance model. This novel nuisance model facilitates maximum-likelihood estimation, but also permits doubly-robust estimation for the parameters of interest. Our approach is illustrated via simulations and a data analysis. An R ...
