We investigate the effect of unobserved heterogeneity in the context of the linear transformation model for censored survival data in the clinical trials setting. The unobserved heterogeneity is represented by a frailty term, with unknown distribution, in the linear transformation model. The bias of the estimate under the assumption of no unobserved heterogeneity when it truly is present is obt...

Family survival data can be used to estimate the degree of genetic and environmental contributions to the age at onset of a disease or of a specific event in life. The data can be modeled with a correlated frailty model in which the frailty variable accounts for the degree of kinship within the family. The heritability (degree of heredity) of the age at a specific event in life (or the onset of...

Interval-censored data occur naturally in many fields and the main feature is that the failure time of interest is not observed exactly, but is known to fall within some interval. In this paper, we propose a semiparametric probit model for analyzing case 2 interval-censored data as an alternative to the existing semiparametric models in the literature. Specifically, we propose to approximate th...

To study disease association with risk factors in epidemiologic studies, cross-sectional sampling is often more focused and less costly for recruiting study subjects who have already experienced initiating events. For time-to-event outcome, however, such a sampling strategy may be length biased. Coupled with censoring, analysis of length-biased data can be quite challenging, due to induced info...

A typical indemnification clause requires the indemnitor to “indemnify and hold the indemnitee harmless.” It might also require the indemnitor to “defend” the indemnitee. While most legal authorities agree that the obligation to defend is different from the obligations to indemnify and hold harmless, many regard the promises to indemnify and hold harmless as synonymous, suggesting that either b...

Medical cost estimation is a challenging task when censoring of data is present. Although researchers have proposed methods for estimating mean costs, these are often derived from theory and are not always easy to understand. We provide an alternative method, based on a replace-from-the-right algorithm, for estimating mean costs more efficiently. We show that our estimator is equivalent to an e...

Objective: To identify the indications for hysterectomy, preoperative assessment, and available alternatives required prior to hysterectomy. Patient self-reported outcomes of hysterectomy have revealed high levels of patient satisfaction.These may be maximized by careful preoperative assessment and discussion of other treatment choices. In most cases hysterectomy is performed to relieve symptom...

Structural Issues in the Conduct of Trials The present structure for administering multicenter clinical trials funded by the government was established by the Greenberg Report1 and first implemented by the Coronary Drug Project.2 Referred to as the National Institutes of Health (NIH) clinical trial model (Figure 1), this example became the standard for trials sponsored by the National Heart, Lu...

Clinical trial related injury and serious adverse events (SAE) are a major area of concern. In all such scenarios the investigator is responsible for medical care of the trial participant and also ethically bound to report the event to all the stakeholders of the clinical trial. The trial sponsor is responsible for ongoing safety evaluation of the investigational product, reporting and compensa...