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Modern datasets commonly feature both substantial missingness and many variables of mixed data types, which present significant challenges for estimation and inference. Complete case analysis, which proceeds using only the observations with…

Methodology · Statistics 2023-04-10 Joseph Feldman , Daniel R. Kowal

Trial-based economic evaluations are typically performed on cross-sectional variables, derived from the responses for only the completers in the study, using methods that ignore the complexities of utility and cost data (e.g. skewness and…

Methodology · Statistics 2018-05-21 Andrea Gabrio , Michael J. Daniels , Gianluca Baio

We propose a general modeling framework for marked Poisson processes observed over time or space. The modeling approach exploits the connection of the nonhomogeneous Poisson process intensity with a density function. Nonparametric Dirichlet…

Methodology · Statistics 2011-11-02 Matthew A. Taddy , Athanasios Kottas

Within Bayesian nonparametrics, dependent Dirichlet process mixture models provide a highly flexible approach for conducting inference about the conditional density function. However, several formulations of this class make either rather…

Methodology · Statistics 2024-05-14 María Xosé Rodríguez-Álvarez , Vanda Inácio , Nadja Klein

Missing data is inevitable in longitudinal clinical trials. Conventionally, the missing at random assumption is assumed to handle missingness, which however is unverifiable empirically. Thus, sensitivity analysis is critically important to…

Methodology · Statistics 2022-03-18 Siyi Liu , Shu Yang , Yilong Zhang , Guanghan , Liu

Directional data require specialized probability models because of the non-Euclidean and periodic nature of their domain. When a directional variable is observed jointly with linear variables, modeling their dependence adds an additional…

Methodology · Statistics 2022-12-22 Tong Zou , Hal S. Stern

We present a new procedure for conducting a sensitivity analysis in matched observational studies. For any candidate test statistic, the approach defines tilted modifications dependent upon the proposed strength of unmeasured confounding.…

Methodology · Statistics 2025-03-14 Colin B. Fogarty

Analysis of longitudinal randomised controlled trials is frequently complicated because patients deviate from the protocol. Where such deviations are relevant for the estimand, we are typically required to make an untestable assumption…

Methodology · Statistics 2018-05-16 Suzie Cro , James R Carpenter , Michael G Kenward

While sensitivity analysis improves the transparency and reliability of mathematical models, its uptake by modelers is still scarce. This is partially explained by its technical requirements, which may be hard to understand and implement by…

Applications · Statistics 2023-03-20 Arnald Puy , Pamphile T. Roy , Andrea Saltelli

Understanding and interpreting how machine learning (ML) models make decisions have been a big challenge. While recent research has proposed various technical approaches to provide some clues as to how an ML model makes individual…

Machine Learning · Computer Science 2018-11-09 Wenbo Guo , Sui Huang , Yunzhe Tao , Xinyu Xing , Lin Lin

Identifying causal treatment (or exposure) effects in observational studies requires the data to satisfy the unconfoundedness assumption which is not testable using the observed data. With sensitivity analysis, one can determine how the…

Methodology · Statistics 2023-01-31 Yang Ou , Lu Tang , Chung-Chou H. Chang

Matching is a commonly used causal inference study design in observational studies. Through matching on measured confounders between different treatment groups, valid randomization inferences can be conducted under the no unmeasured…

Methodology · Statistics 2024-09-20 Jeffrey Zhang , Siyu Heng

Prior sensitivity examination plays an important role in applied Bayesian analyses. This is especially true for Bayesian hierarchical models, where interpretability of the parameters within deeper layers in the hierarchy becomes…

Methodology · Statistics 2013-12-18 Malgorzata Roos , Thiago G. Martins , Leonhard Held , Havard Rue

We present a framework for generating multiple imputations for continuous data when the missing data mechanism is unknown. Imputations are generated from more than one imputation model in order to incorporate uncertainty regarding the…

Applications · Statistics 2013-01-14 Juned Siddique , Ofer Harel , Catherine M. Crespi

In this paper, a scale mixture of Normal distributions model is developed for classification and clustering of data having outliers and missing values. The classification method, based on a mixture model, focuses on the introduction of…

Machine Learning · Statistics 2017-11-23 G. Revillon , A. Djafari , C. Enderli

Robust tracking of a target in a clutter environment is an important and challenging task. In recent years, the nearest neighbor methods and probabilistic data association filters were proposed. However, the performance of these methods…

Machine Learning · Computer Science 2020-12-18 Bahman Moraffah , Christ Richmond , Raha Moraffah , Antonia Papandreou-Suppappola

We propose an empirical Bayes estimator based on Dirichlet process mixture model for estimating the sparse normalized mean difference, which could be directly applied to the high dimensional linear classification. In theory, we build a…

Machine Learning · Statistics 2017-02-17 Yunbo Ouyang , Feng Liang

Methods for addressing missing data have become much more accessible to applied researchers. However, little guidance exists to help researchers systematically identify plausible missing data mechanisms in order to ensure that these methods…

Applications · Statistics 2020-07-29 Adam Davey , Ting Dai

We present a Bayesian model for estimating the joint distribution of multivariate categorical data when units are nested within groups. Such data arise frequently in social science settings, for example, people living in households. The…

Methodology · Statistics 2016-10-31 Jingchen Hu , Jerome P. Reiter , Quanli Wang

A sensitivity analysis in an observational study assesses the robustness of significant findings to unmeasured confounding. While sensitivity analyses in matched observational studies have been well addressed when there is a single outcome…

Methodology · Statistics 2015-11-05 Colin B. Fogarty , Dylan S. Small