The assessment of health risks due to low levels of exposure to potential environmental hazards based on the results of toxicological experiments necessarily involves extrapolation of results obtained at relatively high doses to the low dose region of interest. In this paper, different statistical extrapolation procedures which take into account both time-to-response and the presence of competing risks are compared using a large simulated data base. The study was designed to cover a range of plausible dose response models as well as to assess the effects of competing risks, background response, latency and experimental design on the performance of the different extrapolation procedures. It was found that point estimates of risk in the low dose region may differ from the actual risk by a factor of 1000 or more in certain situations, even when precise information on the time of occurrence of the particular lesion of interest is available. Although linearized upper confidence limits on risk can be highly conservative when the underlying dose response curve is sublinear in the low dose region, they were found not to exceed the actual risk in the low dose region by more than a factor of 10 in those cases where the underlying dose response curve was linear at low doses.

Animals↗

PubMedDate not supplied

W. Edwards Deming and total quality management: an interpretation for nursing practice.

The purpose of this article is to introduce nurses to W. Edwards Deming and the 14 points of his management philosophy, the basis of total quality management (TQM) (Deming, 1986). Each of Deming's points has been subject to in-depth analysis from business executives for the past 40 years. Quality improvement is at the very center of TQM. To adopt TQM will require a major thought transformation for many nursing leaders, but the benefits that nurses and the profession as a whole can reap from this revolutionary style of management make the effort to change worthwhile. If you are not satisfied with the status quo and are looking for a better way to conduct business, the information in this article will begin to define quality improvement and will help you strive for the highest possible level of service to your ultimate customer--the patient.

Japan↗