Application of Markov chain Monte Carlo methods to modelling birth prevalence of Down syndrome

Data collected before the routine application of prenatal screening are of unique value in estimating the natural live-birth prevalence of Down syndrome. However, much of these data are from births from over 20 years ago and they are of uncertain quality. In particular, they are subject to varying degrees of underascertainment. Published approaches have used ad hoc corrections to deal with this problem or have been restricted to data sets in which ascertainment is assumed to be complete. In this paper we adopt a Bayesian approach to modelling ascertainment and live-birth prevalence. We consider three prior specifications concerning ascertainment and compare predicted maternal-age-specific prevalence under these three different prior specifications. The computations are carried out by using Markov chain Monte Carlo methods in which model parameters and missing data are sampled.     

The paradox of multiple elections

Assume that voters must choose between voting yes (Y) and voting no (N) on three propositions on a referendum. If the winning combination is NYY on the first, second, and third propositions, respectively, the paradox of multiple elections is that NYY can receive the fewest votes of the 2³ = 8 combinations. Several variants of this paradox are illustrated, and necessary and sufficient conditions for its occurrence, related to the “incoherence” of support, are given. The paradox is shown, via an isomorphism, to be a generalization of the well-known paradox of voting. One real-life example of the paradox involving voting on propositions in California, in which not a single voter voted on the winning side of all the propositions, is given. Several empirical examples of variants of the paradox that manifested themselves in federal elections – one of which led to divided government – and legislative votes in the US House of Representatives, are also analyzed. Possible normative implications of the paradox, such as allowing voters to vote directly for combinations using approval voting or the Borda count, are discussed. Received: 31 July 1996 / Accepted: 1 October 1996     

Quality. A tightrope for the '90s

How accurately can you measure quality of care in health care? Recently, HMOs and other types of managed care organizations have been in the process of defining quality in quantitative terms. Physicians who utilize fewer resources and who care for more patients per-unit-of-time are valued as providing better care than colleagues who may work at a slower (more expensive?) pace. The pressure to evaluate or treat greater numbers of patients in shorter periods of time can produce adverse consequences. And numbers do not necessarily take into account the quality of the care delivered. There is clearly a middle road. Physicians must take care of a sufficient number of patients with a given problem to gain and maintain expertise and mastery. But they must also guard against the insidious pressure for the procedure to become the end in itself.     

Clinical reengineering. A benchmark strategy

The health care provider marketplace continues to undergo dramatic changes with the advent of hospital mergers, acquisitions, and physician and hospital alliances. In this era of managed care, cost containment is still vital to a hospital's success, but many stakeholders--patients, employers, and physicians--are determined that quality of care also remain paramount. How can hospitals reduce their expenses and maintain a quality focus? The answer lies in a successful clinical reengineering initiative. One progressive model of clinical reengineering is presented, as well as examples of initiatives at three health care institutions. Initial results of clinical redesign programs have been dramatic and encouraging, with documented evidence of simultaneous cost savings and improved patient care.     

Physician leadership. Physician executives share insights

Senior physician executives were asked to share their insights about how the medical management field has evolved. The Physician Executive Management Center, a Tampa, Florida-based search firm, has been surveying senior physician executives each year for the past decade. This year's report on physician executive compensation and duties in hospitals, managed care organizations, and group practices provides an excellent picture of the growth of the profession, as well as a broad perspective of anticipated changes for the future of medical management. The respondents addressed the following questions: What are the skills necessary for success? How have their jobs changed over the years? Have they made the right choice in pursuing medical management careers?     

The medical practice as business organization

Medical practices historically have not been examined in terms of their organizational structures and of the appropriateness of their structures for survival as business entities. In this paper, we propose a model for the typical medical practice and discuss its fit with current organizational theory. It is apparent that the medical practice organization does not fit with the demands of a rapidly changing and complex environment. To survive and grow, the medical practice organization must align itself with others that have an interest and stake in the health care system, develop teamwork among physicians, bridge the gap between physicians and others in the organization, and recognize that the work done in the organization depends on other components of the organization.     

The new academic health center hybrids: part business, part academic

Academic health centers have flourished since the 1960s and even managed to survive the shift toward prospective payment. But in their current quest to expand the number of managed care patients and compete with the private sector, they often must price services below cost and reduce the number of faculty members and other personnel. Unless their prices are competitive, managed care companies will not do business with them. AHCs that cannot compete find they are overbedded, underused, and in turmoil. This article explores what successful AHCs are doing to stay healthy in the managed care era.     

Next-generation informatics. A new picture of quality medicine

It's up to the physician executive to make an informed choice when selecting a "next-generation" information system. Look for systems that truly integrate (not merely interface) managed care components, clinical capabilities, and other features in a model that mimics the workflow of an actual practice. Take the time to learn about the technology. Consider how a vendor's product will work at every point within your organization. Seven critical features that physician executives should consider in their decision-making are described.     

Demographic transition theory

Demography is a science short on theory, rich in quantification. Nevertheless, demography has produced one of the best documented generalizations in the social sciences: the demographic transition. What is the demographic transition? Stripped to its essentials it is the theory that societies progress from a pre-modern regime of high fertility and high mortality to a post-modern regime of low fertility and low mortality. The cause of the transition has been sought in the reduction of the death rate by controlling epidemic and contagious diseases. Then, with modernization, children become more costly. Cultural changes weaken the importance of children. The increasing empowerment of women to make their own reproductive decisions leads to smaller families. Thus there is a change in values, emphasizing the quality of children rather than their quantity. In short, the fertility transition is becoming universal phenomenon, in which every country may be placed on a continuum of progress in the transition.