Showing papers by "Ingram Olkin published in 2016"

Impact of surgery for stage IA non-small-cell lung cancer on patient quality of life.

Abstract: Background There is a paucity of literature comparing quality of life (QoL) before and after surgery in stage IA lung cancer, where surgical resection is the recommended curative treatment. Objective To assess the impact of surgery on physical and mental health-related QoL in patients with stage IA lung cancer treated with surgical resection. Methods Participants in the I-ELCAP cohort who were diagnosed with their first primary pathologic stage IA non-small-cell lung cancer, underwent surgery, and provided follow-up information on QoL 1 year later were included in the present analysis (N = 107). QoL information was collected using the SF-12 (12-item Short Form Health Survey), which generates 2 component scores related to mental health and physical health. Results Statistical analyses indicated that physical health QoL was significantly worsened from before surgery to after surgery, whereas mental health QoL marginally improved from before to after surgery. Physical health QoL worsened for women from baseline to follow-up, but not for men. Only lobectomy (not limited resection) had an impact on QoL from before to after surgery. Limitations Results are considered preliminary given the small sample size and multiple comparisons. Conclusions The current study findings have implications for lung cancer health care professionals in regard to how they can most effectively present the possible impact of surgery on quality of life to this subset of patients in which disease has not yet significantly progressed.

Overlap between treatment and control distributions as an effect size measure in experiments.

Abstract: The proportion π of treatment group observations that exceed the control group mean has been proposed as an effect size measure for experiments that randomly assign independent units into 2 groups. We give the exact distribution of a simple estimator of π based on the standardized mean difference and use it to study the small sample bias of this estimator. We also give the minimum variance unbiased estimator of π under 2 models, one in which the variance of the mean difference is known and one in which the variance is unknown. We show how to use the relation between the standardized mean difference and the overlap measure to compute confidence intervals for π and show that these results can be used to obtain unbiased estimators, large sample variances, and confidence intervals for 3 related effect size measures based on the overlap. Finally, we show how the effect size π can be used in a meta-analysis.

Life Distributions: A Brief Discussion

Abstract: This article presents a brief description of some of the characteristics of life distributions that arise in survival analysis and reliability theory. Alternative definitions of a distribution are discussed and related to a variety of stochastic orders: hazard rate order, likelihood ratio order, convex order, Lorenz order. Nonparametric families, particularly log-concave densities, completely monotone distributions, increasing hazard rate families, new-better-than-used families, and bathtub hazard rate families are analyzed. A taxonomy for semiparametric families is presented and the effect of introducing parameters on various stochastic orders is shown. Finally, the introduction of covariate models in these families is developed.

A cooperative effort of the Clinical Epidemiology Unit of the Istituto Dermopatico dell'Immacolata-Istituto di Ricovero e Cura a Carattere Scientifico (IDI-IRCCS) and the Archives of Dermatology A Comparison of Dermatologists' and Primary Care Physicians' Accuracy in Diagnosing Melanoma

Abstract: Data Sources: Studies published between January 1966 and October 1999 in the MEDLINE, EMBASE, and CancerLit databases; reference lists of identified studies; abstracts from recent conference proceedings; and direct contact with investigators. Medical subject headings included melanoma, diagnosis, screening, primary care, family practitioner, general practitioner, internal medicine, dermatologist, and skin specialist. Articles were restricted to those involving human subjects.