In many clinical trials, such as those undertaken by large cooperative cancer groups (CALGB, ECOG, SWOG, EORTC), patients are randomized to one of two treatments within an institution (a hospital orâ€¦ (More)

The focus of this article is to determine the probability of making transitions through various ADL limitation levels, controlling for gender, age, and baseline ADL level, and using death as aâ€¦ (More)

In this paper, we consider the problem of regression analysis for data which consist of a large number of independent small groups or clusters of correlated observations. Instead of using theâ€¦ (More)

Linear regression is one of the most popular statistical techniques. In linear regression analysis, missing covariate data occur often. A recent approach to analyse such data is a weighted estimatingâ€¦ (More)

Studies of agreement commonly occur in psychiatric research. For example, researchers are often interested in the agreement among radiologists in their review of brain scans of elderly patients withâ€¦ (More)

This paper describes the QUality and Experience Metric (QUEM), a method for estimating the skill level of a knowledgebased system based on the quality of the solutions it produces. It allows one toâ€¦ (More)

1 Summary Missing covariate data is a common problem that complicates the fitting of regression models (e.g., generalized linear models) in many applications. A recently developed technique forâ€¦ (More)

In comparing two treatments with failure time observations, conÂ®dence bands for the `Ì€ difference'' of two survival curves provide useful information about a global picture of the treatmentâ€¦ (More)

In survival analysis, estimates of median survival times in homogeneous samples are often based on the Kaplan-Meier estimator of the survivor function. Confidence intervals for quantiles, such asâ€¦ (More)