One approach to evaluating the strength of association between a longitudinal marker process and a key clinical event time is through predictive regression methods such as a time-dependent covariate hazard model. For example, a time-varying covariate Cox model specifies the instantaneous risk of...

Background: The aging process can be described as the change in health-related variables over time. Unfortunately, simple graphs of available data may be misleading if some people die, since they may confuse patterns of mortality with patterns of change in health. Methods have been proposed to...

A common problem for comparing the relative accuracy of two screening tests for Alzheimer's disease (D) in a two-stage design study is verification bias. If the verification bias can be assumed to be ignorable, Zhou and Higgs (2000) have proposed a maximum likelihood approach to compare the...

In a gene expression array study, the expression levels of thousands of genes are monitored simultaneously across various biological conditions on a small set of subjects. One goal of such studies is to explore a large pool of genes in order to select a subset of genes that appear to be...

We extend the marginalized transition model of Heagerty (2002) to accommodate nonignorable monotone dropout. Using a selection model, weakly identified dropout parameters are held constant and their effects evaluated through sensitivity analysis. For data missing at random (MAR), efficiency of...

A common goal in microarray experiments is to identify genes that are differentially expressed among two or more biological conditions. There is currently no standard methodology for detecting differential expression in time course studies. However, it is clear that monitoring the behavior of...

This work addresses the problem of extracting signal content from protein mass spectrometry data. A multiscale decomposition of these spectra is used to focus on local scale-based structure and provide an unambiguous definition of scale-specific features. An objective quantification of...

The case-crossover design uses cases only, and compares exposures just prior to the event times to exposures at comparable control, or "referent" times, in order to assess the effect of short-term exposure on the risk of a rare event. It has commonly been used to study the effect of air...

In evaluation of diagnostic accuracy of tests, a gold standard on the disease status is required. However, in many complex diseases, it is impossible or unethical to obtain such the gold standard. If an imperfect standard is used as if it were a gold standard, the estimated accuracy of the tests...

In economic anthropology, the concept of 'market' needs a more detailed elaboration. The traditional distinction between barter and price markets does not suffice. One of the identifiable forms of market in anthropology is the individualized, "subjective" market which is defined by the question:...