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At least 19 recordsLinked to original sources
PubMed1983

Improving the accuracy of migration age detail in multiple-area population forecasts.

Population projections are often required for many geographical areas, and must be prepared with maximal computer and minimal analytical effort. At the same time, realistic age detail forecasts require a flexible means of treating age-specific net migration. This report presents a migration projection technique compatible with these constraints. A simplified version of Pittenger's model is used, where future migration patterns are automatically assigned from characteristics of historical patterns. A comparative test of age pattern accuracy for 1970-1980 indicates that this technique is superior to the commonly used plus-minus adjustment to historical rates.

Adolescent↗
PubMed1991

An empirical analysis of the effect of length of forecast horizon on population forecast errors.

Many studies have found that population forecast errors generally increase with the length of the forecast horizon, but none have examined this relationship in detail. Do errors grow linearly, exponentially, or in some other manner as the forecast horizon becomes longer? Does the error-horizon relationship differ by forecasting technique, launch year, size of place, or rate of growth? Do alternative measures of error make a difference? In this article we address these questions using two simple forecasting techniques and population data from 1900 to 1980 for states in the United States. We find that in most instances there is a linear or nearly linear relationship between forecast accuracy and the length of the forecast horizon, but no consistent relationship between bias and the length of the horizon. We believe that these results provide useful information regarding the nature of population forecast errors.

Humans↗
PubMed1986

Population forecasts and confidence intervals for Sweden: a comparison of model-based and empirical approaches.

This paper compares several methods of generating confidence intervals for forecasts of population size. Two rest on a demographic model for age-structured populations with stochastic fluctuations in vital rates. Two rest on empirical analyses of past forecasts of population sizes of Sweden at five-year intervals from 1780 to 1980 inclusive. Confidence intervals produced by the different methods vary substantially. The relative sizes differ in the various historical periods. The narrowest intervals offer a lower bound on uncertainty about the future. Procedures for estimating a range of confidence intervals are tentatively recommended. A major lesson is that finitely many observations of the past and incomplete theoretical understanding of the present and future can justify at best a range of confidence intervals for population projections. Uncertainty attaches not only to the point forecasts of future population, but also to the estimates of those forecasts' uncertainty.

Forecasting↗
PubMed1996

On the utility of population forecasts.

Many customers demand population forecasts, particularly for small areas. Although the forecast evaluation literature is extensive, it is dominated by a focus on accuracy. We go beyond accuracy by examining the concept of forecast utility in an evaluation of a sample of 2,709 counties and census tracts. We find that forecasters provide "value-added" knowledge for areas experiencing rapid change or areas with relatively large populations. For other areas, reduced value is more common than added value. Our results suggest that new forecasting strategies and methods such as composite modeling may substantially improve forecast utility.

Bias↗
PubMed1978

Population forecasts for health planning: an assessment of the state of the art.

Health planning agencies make use of age-sex detailed forecasts of population. This article evaluates sources of forecasts, notes the essential role of assumptions in forecasts, and indicates the general quality of techniques for projecting components of population change. It clarifies for health planners what demographers can--and can not--deliver.

Demography↗
PubMed1988

Stability over time in the distribution of population forecast errors.

A number of studies in recent years have investigated empirical approaches to the production of confidence intervals for population projections. The critical assumption underlying these approaches is that the distribution of forecast errors remains stable over time. In this article, we evaluate this assumption by making population projections for states for a number of time periods during the 20th century, comparing these projections with census enumerations to determine forecast errors, and analyzing the stability of the resulting error distributions over time. These data are then used to construct and test empirical confidence limits. We find that in this sample the distribution of absolute percentage errors remained relatively stable over time and data on past forecast errors provided very useful predictions of future forecast errors.

Demography↗
PubMed1997

A theory of technophysio evolution, with some implications for forecasting population, health care costs, and pension costs.

We argue that over the past 300 years human physiology has been undergoing profound environmentally induced changes made possible by numerous advances in technology. These changes, which we call technophysio evolution, increased body size by over 50%, and greatly improved the robustness and capacity of vital organ systems. Because technophysio evolution is still ongoing, it is relevant to forecasts of longevity and morbidity and, therefore, to forecasts of the size of the elderly population and pension and health care costs.

Europe↗
PubMed1996

Bayesian forecasting in paediatric populations.

Bayesian forecasting offers several important advantages for dosage individualisation in children, although, unlike for adults, its use in this population is much lower. Indeed, currently Bayesian methods are underused in this patient population. The paucity of paediatric population pharmacokinetic parameters, and the unavailability of specific clinical pharmacokinetic software for the whole paediatric population, are the main limitations to the application of Bayesian methods in these patients. When these problems have been overcome, this approach will allow clinicians to achieve therapeutic concentrations more readily, faster and more precisely, thus making the methodology highly attractive in the paediatric setting.

Adolescent↗
PubMed1993

[Projection of new cancer diseases to the year 2002--a contribution to health planning in public health by the Saarland cancer registry].

This paper provides projections of incident cases of malignant neoplasms in Saarland, Germany, between 1988 and 2002. The analyses are based on population forecasts by the National Statistical Office and on age-cohort analyses of cancer incidence data from the population-based cancer registry of the Saarland. Due to dramatic demographic changes and increasing age-specific cancer incidence rates, the average yearly number of total incident cases of malignant neoplasms is projected to increase by 63.1% between 1983-1987 and 1998-2002 in men, with the strongest increase projected for colon cancer (+114.6%). In women, a modest increase (+7.1%) is projected for all malignant neoplasms, with stronger increases for colon cancer (+50.1%), lung cancer (+44%) and breast cancer (+27.4%), whereas decreasing annual numbers of cases are projected for cervical cancer (-51.6%), stomach cancer (-18.5%) and endometrial cancer (-10.2%). The results provide a quantitative basis for health care planning in the Saarland. They may also serve as a rough guide for other parts of Germany for which reliable cancer incidence data are not available.

Adolescent↗
PubMed1995

Initialization of warfarin dosages using computer modeling.

OBJECTIVE: Software incorporating warfarin pharmacokinetics and pharmacodynamics, as well as a Bayesian regression method, was evaluated for accuracy in predicting steady-state dosages of warfarin during initialization of anticoagulation therapy. DESIGN: A cohort study was used to compare computer predictions with physician-determined doses during a retrospective chart review of 42 patients. PATIENTS: Forty-two patient charts were selected for monitoring anticoagulation initialization therapy. Of the 42 patients reviewed, 22 were excluded on the following bases: uncontrolled congestive heart failure; ongoing treatment with medications that interfered with warfarin metabolism or displaced warfarin from protein binding sites; recent treatment with fresh frozen plasma or vitamin K; or any bleeding disorders, sepsis, malabsorption or significant changes in liver and/or renal function. MAIN OUTCOME MEASURES: Using physician-determined International Normalized Ratios (INRs) as target levels for the software, the number of INR feedbacks needed to stabilize blood drug levels during initialization were compared between physicians and computer forecasting. Population parameters and sequentially measured INRs were used for evaluation. RESULTS: Current oral anticoagulation protocols require significantly more measured INRs than computer forecasting to achieve steady-state dosages (9.5 v 4.4, respectively, p < 0.01). Physicians showed a statistically significant pattern of underdosing patients (4.3 v 1.7 subtherapeutic INRs, respectively, p < 0.01). Computer predictions tended to overdose patients but did not significantly increase the number of supratherapeutic INRs. This study showed that five INR inputs consistently gave accurate steady-state dosage predictions, and in many ways computer modeling was more effective than clinician-determined steady-state dosing in warfarin initialization. CONCLUSIONS: Computer modeling provides a reliable means of predicting initialization dosages for warfarin anticoagulation therapy with five INR inputs and therefore has merit in the clinical setting if used with sound clinical judgment.

Adult↗
PubMed1997

[Future population growth in the Augsburg area--model calculations using the DEPOP model].

Regional population forecasts are on average even more uncertain than nationwide projections, due to the greater importance of migration and the unstable smaller absolute numbers. Other than national projections, local or regional calculations do normally have an explicit goal. In this paper, a projection of the population and age structure in the region of Augsburg is used to demonstrate some specific aspects of local population projections used for public health purposes. If institutions of childhood ages are to be projected the results are primarily determined by the assumptions on migration. If questions of old age are to be answered, the main factor of influence is the development in mortality. Depending on the specific alm of a local population projection, the principal insecurity about the future should be integrated by calculating confidence bands for those demographic parameters, that are most important for the specific question.

Adolescent↗
PubMed1987

Impact of growing numbers of the very old on Medicaid expenditures for nursing homes: a multi-state, population-based analysis.

We utilized Medicaid data from five states which account for 39 per cent of Medicaid expenditures to study the impact of the near-trebling of persons age 85 and older (the very old) projected to occur by the year 2012 upon Medicaid nursing home expenditures. We found a one-year prevalence of Medicaid-covered nursing home residence of 20 per 100 among the very old. If this rate continues, with no changes in current levels of Medicaid nursing home payments, and if population forecasts are accurate, increasing numbers of the very old will generate an additional +6.3 billion (1982 dollars) annually of Medicaid nursing home payments by 2012: an increase of 280 per cent from 1982 levels. The stress this trend will place upon societal ability to check growth in public expenditures for medical care while maintaining basic services for other low income populations will be an important force shaping public health policy in the next 25 years.

Aged↗