The …eld of survival analysis has experienced tremendous growth during the latter half of the 20th century. The methodological developments of survival analysis that have had the most profound impact are the Kaplan-Meier method for estimating the survival function, the log-rank test for comparing the equality of two or more survival distributions, and the Cox proportional hazards (PH) model for...

A unified implementation of parametric proportional hazards (PH) and accelerated failure time (AFT) models for right-censored or intervalcensored and left-truncated data is described. The description here is válid for time-constant covariates, but the necessary modifications for handling time-varying covariates are implemented in eha. Note that only piecewise constant time variation is handled.

Background: Thalassemia major (TM) is a severe disease and the most common anemia worldwide. The survival time of the disease and its risk factors are of importance for physicians. The present study was conducted to apply the semi-parametric Cox PH model and use parametric proportional hazards (PH) and accelerated failure time (AFT) models to identify the risk factors related to survival of TM ...

Excess food intake leads to obesity and diabetes, both of which are well-known independent risk factors for atherosclerosis, and both of which are growing epidemics in an aging population. We hypothesized that aging enhances the metabolic and vascular effects of high fat diet (HFD) and therefore examined the effect of age on atherosclerosis and insulin resistance in lipoprotein receptor knockou...

In large cohort studies, it often happens that some covariates are expensive to measure and hence only measured on a validation set. On the other hand, relatively cheap but error-prone measurements of the covariates are available for all subjects. Regression calibration (RC) estimation method (Prentice, 1982, Biometrika 69, 331-342) is a popular method for analyzing such data and has been appli...

We describe the second of two large-scale atomic simulation projects on materials failure performed on the 12-teraflop ASCI (Accelerated Strategic Computing Initiative) White computer at the Lawrence Livermore National Laboratory. This investigation simulates ductile failure by using more than one billion atoms where the true complexity of the creation and interaction of hundreds of dislocation...

As product development cycles become shorter, and companies demand more rapid achievement of reliability goals, it is becoming more and more important to use quantitative Accelerated Life Tests (ALT) to predict and improve reliability. Today there is an abundance of methods to plan and analyze accelerated tests, but there are also many pitfalls. This paper identifies some major problems and con...

The accelerated failure time model provides a natural formulation of the effects of covariates on potentially censored response variable. The existing semiparametric estimators are computationally intractable and statistically inefficient. In this article we propose an approximate nonparametric maximum likelihood method for the accelerated failure time model with possibly time-dependent covaria...

Accelerated failure time (AFT) models are useful regression tools to study the association between a survival time and covariates. Semiparametric inference procedures have been proposed in an extensive literature. Among them, Fygenson and Ritov (1994) proposed an estimating equation which is monotone in the regression parameter and has some excellent properties. However, there exists a serious ...

Right-censored time-to-event data are sometimes observed from a (sub)cohort of patients whose survival times can be subject to outcome-dependent sampling schemes. In this paper, we propose a unified estimation method for semiparametric accelerated failure time models under general biased estimating schemes. The proposed estimator of the regression covariates is developed upon a bias-offsetting ...