Nonparametric Estimation of the Hazard Function from Censored Data

Nonparametric Estimation of the Hazard Function from Censored Data PDF Author: Martin Abba Tanner
Publisher:
ISBN:
Category : Nonparametric statistics
Languages : en
Pages : 194

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Nonparametric Estimation of the Hazard Function from Censored Data

Nonparametric Estimation of the Hazard Function from Censored Data PDF Author: Martin Abba Tanner
Publisher:
ISBN:
Category : Nonparametric statistics
Languages : en
Pages : 194

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Nonparametric Estimation of the Survival Function for Censored Data

Nonparametric Estimation of the Survival Function for Censored Data PDF Author: Lawrence Victor Rubinstein
Publisher:
ISBN:
Category : Characteristic functions
Languages : en
Pages : 146

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A Nonparametric Estimation of the Cumulative Hazard Function Based on Subsets of Censored Survival Data

A Nonparametric Estimation of the Cumulative Hazard Function Based on Subsets of Censored Survival Data PDF Author: Yuri Beljaev
Publisher:
ISBN:
Category :
Languages : en
Pages : 78

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Nonparametric Hazard Rate Estimation with Left Truncated and Right Censored Data

Nonparametric Hazard Rate Estimation with Left Truncated and Right Censored Data PDF Author: Jufen Chu
Publisher:
ISBN:
Category : Censored observations (Statistics)
Languages : en
Pages : 186

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Book Description
Nonparametric estimation of the hazard rate function, based on data modified by left truncation and/or right censoring, is considered. The hazard rate is not integrable over its support and hence it is traditionally estimated over a fixed interval under the mean integrated squared error (MISE) criterion. It is well known in the literature that neither left truncation nor right censoring affect the rate of the MISE convergence, but so far no results on how the modified data and the interval of estimation affect the MISE convergence have been known. To understand the affect, asymptotic theory of sharp minimax estimation is developed which indicates how the modified data and the interval of estimation affect the MISE convergence. The theory is complemented by presenting a data-driven estimator for small samples which is tested on numerical simulations and real data.

Nonparametric Survival Analysis Under Shape Restrictions

Nonparametric Survival Analysis Under Shape Restrictions PDF Author: Shabnam Fani
Publisher:
ISBN:
Category : Failure time data analysis
Languages : en
Pages : 126

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The main problem studied in this thesis is to analyse and model time-to- event data, particularly when the survival times of subjects under study are not exactly observed. One of the primary tasks in the analysis of survival data is to study the distribution of the event times of interest. In order to avoid strict assumptions associated with a parametric model, we resort to nonparametric methods for estimating a function. Although other nonparametric approaches, such as Kaplan-Meier, kernel-based, and roughness penalty methods, are popular tools for solving function estimation problems, they suffer from some non-trivial issues like the loss of some important information about the true underlying function, difficulties with bandwidth or tuning parameter selection. In contrast, one can avoid these issues at the cost of enforcing some qualitative shape constraints on the function to be estimated. We confine our survival analysis studies to estimating a hazard function since it may make a lot of practical sense to impose certain shape constraints on it. Specifically, we study the problem of nonparametric estimation of a hazard function subject to convex shape restrictions, which naturally entails monotonicity constraints. In this thesis, three main objectives are addressed. Firstly, the problem of nonparametric maximum-likelihood estimation of a hazard function under convex shape restrictions is investigated. We introduce a new nonparametric approach to estimating a convex hazard function in the case of exact observations, the case of interval-censored observations, and the mixed case of exact and interval-censored observations. A new idea to handle the problem of choosing the minimum of a convex hazard function estimate is proposed. Based on this, a new fast algorithm for nonparametric hazard function estimation under convexity shape constraints is developed. Theoretical justification for the convergence of the new algorithm is provided. Secondly, nonparametric estimation of a hazard function under smoothness and convex shape assumptions is studied. Particularly, our nonparametric maximum-likelihood approach is generalized for smooth estimation of a function by applying a higher-order smoothness assumption of an estimator. We also evaluate the performance of the estimators using simulation studies and real-world data. Numerical studies suggest that the shape-constrained estimators generally outperform their unconstrained competitors. Moreover, the empirical results indicate that the smooth shape-restricted estimator has more capability to model human mortality data compared to the piecewise linear continuous estimator, specifically in the infant mortality phase. Lastly, our nonparametric estimation of a hazard function approach under convex shape restrictions is extended to the Cox proportional hazards model. A new algorithm is also developed to estimate both convex baseline hazard function and the effects of covariates on survival times. Numerical studies reveal that our new approaches generally dominate the traditional partial likelihood method in the case of right-censored data and the fully semiparametric maximum likelihood estimation method in the case of interval-censored data. Overall, our series of studies show that the shape-restricted approach tends to provide more accurate estimation than its unconstrained competitors, and further investigations in this direction can be highly fruitful.

Nonparametric Estimation of Density and Hazard Rate Functions when Samples are Censored

Nonparametric Estimation of Density and Hazard Rate Functions when Samples are Censored PDF Author: W. J. Padgett
Publisher:
ISBN:
Category :
Languages : en
Pages : 33

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Book Description
The purpose of this article is to present the different types of nonparametric density estimates that have been proposed for the situation that the sample data are censored or incomplete. This type of data arises in many life testing situations and is common in survival analysis problems. Many of the methods of nonparametric density and hazard rate estimation from right-censored observations are discussed. These include histogram and kernel-type procedures, likelihood methods, Fourier series methods, and Bayesian nonparametric approaches. Examples of kernel density estimates are given for mechanical switch life data where data-based choices of the bandwidth values are used. Originator-supplied keywords included: Nonparametric density estimation; Random censorship; Failure rate; Kernel density estimator; Likelihood methods.

The Statistical Analysis of Interval-censored Failure Time Data

The Statistical Analysis of Interval-censored Failure Time Data PDF Author: Jianguo Sun
Publisher: Springer
ISBN: 0387371192
Category : Mathematics
Languages : en
Pages : 310

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Book Description
This book collects and unifies statistical models and methods that have been proposed for analyzing interval-censored failure time data. It provides the first comprehensive coverage of the topic of interval-censored data and complements the books on right-censored data. The focus of the book is on nonparametric and semiparametric inferences, but it also describes parametric and imputation approaches. This book provides an up-to-date reference for people who are conducting research on the analysis of interval-censored failure time data as well as for those who need to analyze interval-censored data to answer substantive questions.

Nonparametric estimation in change-point hazard rate models for censored data

Nonparametric estimation in change-point hazard rate models for censored data PDF Author: A. Antoniadis
Publisher:
ISBN:
Category : Time-series analysis
Languages : en
Pages : 24

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Missing and Modified Data in Nonparametric Estimation

Missing and Modified Data in Nonparametric Estimation PDF Author: Sam Efromovich
Publisher: CRC Press
ISBN: 135167983X
Category : Mathematics
Languages : en
Pages : 867

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Book Description
This book presents a systematic and unified approach for modern nonparametric treatment of missing and modified data via examples of density and hazard rate estimation, nonparametric regression, filtering signals, and time series analysis. All basic types of missing at random and not at random, biasing, truncation, censoring, and measurement errors are discussed, and their treatment is explained. Ten chapters of the book cover basic cases of direct data, biased data, nondestructive and destructive missing, survival data modified by truncation and censoring, missing survival data, stationary and nonstationary time series and processes, and ill-posed modifications. The coverage is suitable for self-study or a one-semester course for graduate students with a prerequisite of a standard course in introductory probability. Exercises of various levels of difficulty will be helpful for the instructor and self-study. The book is primarily about practically important small samples. It explains when consistent estimation is possible, and why in some cases missing data should be ignored and why others must be considered. If missing or data modification makes consistent estimation impossible, then the author explains what type of action is needed to restore the lost information. The book contains more than a hundred figures with simulated data that explain virtually every setting, claim, and development. The companion R software package allows the reader to verify, reproduce and modify every simulation and used estimators. This makes the material fully transparent and allows one to study it interactively. Sam Efromovich is the Endowed Professor of Mathematical Sciences and the Head of the Actuarial Program at the University of Texas at Dallas. He is well known for his work on the theory and application of nonparametric curve estimation and is the author of Nonparametric Curve Estimation: Methods, Theory, and Applications. Professor Sam Efromovich is a Fellow of the Institute of Mathematical Statistics and the American Statistical Association.

Nonparametric Hazard Function Estimation from Doubly-censored Data with Application to AIDS

Nonparametric Hazard Function Estimation from Doubly-censored Data with Application to AIDS PDF Author: Robert Elliot Fusaro
Publisher:
ISBN:
Category :
Languages : en
Pages : 230

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