Data with excess zeros arise in many real-world applications involving counts, such as the number of insects along a transect or the number of dental carries in adolescent children. In the healthcare arena, annual healthcare costs, such as Medicaid prescription drug costs, also have excess...

Drug dilution (MIC) and disk diffusion (DIA) are the two common tests to determine pathogen susceptibility to antibiotics. In the drug dilution method, the classification breakpoints are concentrations and based directly on the pharmacokinetics and pharmacodynamics of the drug. For the disk...

In survival analysis, use of the Cox proportional hazards model requires knowledge of all covariates under consideration at every failure time. Since failure times rarely coincide with observation times, time-dependent covariates need to be inferred from the observed values. In this...

Discrete-time Markov chains have been successfully used to investigate treatment programs and health care protocols for chronic diseases. In these situations, the transition matrix, which describes the natural progression of the disease, is often estimated from a cohort observed at common...