Statistics for weighing benefits and harms in a proposed genetic substudy of a randomized cancer prevention trial

Summary.  When evaluating potential interventions for cancer prevention, it is necessary to compare benefits and harms. With new study designs, new statistical approaches may be needed to facilitate this comparison. A case in point arose in a proposed genetic substudy of a randomized trial of tamoxifen versus placebo in asymptomatic women who were at high risk for breast cancer. Although the randomized trial showed that tamoxifen substantially reduced the risk of breast cancer, the harms from tamoxifen were serious and some were life threaten-ing. In hopes of finding a subset of women with inherited risk genes who derive greater bene-fits from tamoxifen, we proposed a nested case–control study to test some trial subjects for various genes and new statistical methods to extrapolate benefits and harms to the general population. An important design question is whether or not the study should target common low penetrance genes. Our calculations show that useful results are only likely with rare high penetrance genes.     

A Sparse Implementation of the Average Information Algorithm for Factor Analytic and Reduced Rank Variance Models

Factor analytic variance models have been widely considered for the analysis of multivariate data particularly in the psychometrics area. Recently Smith, Cullis & Thompson (2001) have considered their use in the analysis of multi‐environment data arising from plant improvement programs. For these data, the size of the problem and the complexity of the variance models chosen to account for spatial heterogeneity within trials implies that standard algorithms for fitting factor analytic models can be computationally expensive. This paper presents a sparse implementation of the average information algorithm (Gilmour, Thompson & Cullis, 1995) for fitting factor analytic and reduced rank variance models.     

Mapping water quality by local scoring

The mean density of bacteria in a water body is commonly monitored using quantal assay. This paper describes the use of local scoring in estimating the spatial distribution of mean density from quantal assay results at a set of point locations. An application to estimating the mean density of fecal conform bacteria in a coastal pond is presented. Model diagnostics based on a parametric bootstrap are also presented.     

The Poverty Reduction Strategy Approach Six Years On: An Examination of Principles and Practice in Uganda

It is over six years since the World Bank and the IMF started promoting a PRS approach to development management in low‐income countries. The 2005 review endorsed the approach, but highlighted the need for a renewed focus on the principles underpinning it: country ownership; results orientation; comprehensiveness; partnership focus; and long‐term outlook. Uganda is often hailed as one of the best PRS performers. This article finds that Uganda's Poverty Eradicaton Action Plan (PEAP) has brought significant gains to development management, but that its performance against several of the PRS principles is disappointing. A return to these principles could improve the practice of the government and development partners around the PEAP – a finding likely to be applicable to many countries implementing a PRS.     

The ascendancy of primary care: permanent or temporary?

The conventional wisdom strongly suggests a health care provider food chain for the future: Primary care physicians (PCPs), principally family practitioners, on the top playing the lead role, distantly followed by specialists, with hospitals and other ancillary services even further down the line. Is this a reasonable expectation? Will PCPs dominate the new systems? Or will they be but one of many equally necessary components of these developing integrated health care delivery organizations? Looking at the various models now developing, it would seem that future integrated delivery systems will utilize both PCPs and specialists, but with strong augmentation from a diverse assortment of other health care professionals, including nonphysician providers, educators, and administrators. To separate the illusion of primary care dominance of the coming health care system from the likely reality, we should first determine what is driving the apparent present demand for primary care physicians. Next, we will examine the possible and probable reactions to that demand from an economic standpoint and from the points of view of both health care professionals and the public. Finally, we must try to picture how health care provider organizations of the future are likely to look and how they will integrate their health care professionals.