SEARCH · PubMed Health

Results for “forecasting”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,639 records · Page 91Linked to original sources

PubMed2006

Medication sales and syndromic surveillance, France.

Although syndromic surveillance systems using nonclinical data have been implemented in the United States, the approach has yet to be tested in France. We present the results of the first model based on drug sales that detects the onset of influenza season and forecasts its trend. Using weekly lagged sales of a selected set of medications, we forecast influenzalike illness (ILI) incidence at the national and regional level for 3 epidemic seasons (2000-01, 2001-02, and 2002-03) and validate the model with real-time updating on the fourth (2003-04). For national forecasts 1-3 weeks ahead, the correlation between observed ILI incidence and forecast was 0.85-0.96, an improvement over the current surveillance method in France. Our findings indicate that drug sales are a useful additional tool to syndromic surveillance, a complementary and independent source of information, and a potential improvement for early warning systems for both epidemic and pandemic planning.

Commerce↗

PubMedDate not supplied

[The theory of functional systems and purposeful behavior].

The role of probability forecasting in the purposive behavior under conditions of subjective uncertainty is considered in terms of the theory of functional systems. Participation of the probability forecasting in the afferent synthesis, goal formation, formation of the acceptor of action result and action program, and, finally, in the action program actualization is substantiated. The model of behavior under conditions of subjective uncertainty is advanced. It includes all the classical elements of the model of behavioral act developed by P.K. Anokhin. In order to take into account the probability aspects of behavior, the role of probability forecasting is emphasized at every stage of the system functioning. In addition to the classical elements, two novel components are introduced. These are the "memory buffer" (results of searching reactions) and the apparatus of probability decisions about changes in the action program. By the memory buffer an apparatus is meant, which gathers and stores the information about the results of many behavioral acts performed during the actualization of the action program. This information is used in the process of making a probability decision as whether to alter or not the action program after each specific behavioral act. Such an approach integrates the probability forecasting and the theory of functional systems. The theory becomes universal, i.e., applicable not only to deterministic but also to probabilistic environments.

Animals↗

PubMed1979

[Experience with the prognosis of strokes].

Results of using discriminant analysis for forecasting ischemic and hemorrhagic strokes are presented. Use was made of clinical data obtained from groups consisting of 400 patients with a history of ischemic strokes, 50 patients with a history of hemorrhagic strokes and 100 healthy individuals. Each observation in these groups was analyzed from 120 parameters and features. As a result of mathematical processing of these data 15 risk factors found to be the most informative for forecasting ischemic strokes, and 16 factors for forecasting hemorrhagic strokes were selected. The reliability of the identification capacity of the prognostic system was evaluated from generalized Machalanobis distance. The correctness of forecasting ischemic strokes was confirmed in 83% and of hemorrhagic strokes in 94.7% of the cases.

Aged↗

PubMedDate not supplied

[New method of epidemiological surveillance of influenza mortality in the USA].

This paper describes a new method of forecasting the expected number of pneumonia and influenza (P and I) deaths on the basis of time-series analysis of historical mortality data. The new method is different in three aspects from the regression method developed by Serfling and used by the Centres for Disease Control (CDC) since 1963 in that it uses the ratio of P and I deaths to deaths from all causes in lieu of the total number of P and I deaths in forecasting the expected numbers. Also, instead of deleting epidemic periods in the forecast, these weeks are replaced by expected numbers. Finally, forecasting is done with a time-series model instead of the regression model.

Adolescent↗

PubMed1995

A computer system for epidemiological surveillance.

In epidemiological surveillance, it is imperative that any unusual increase in reported cases be detected as quickly as possible. In the surveillance unit at "Pedro Kourí," it was necessary to create a computer system for the surveillance of transmissible diseases in order to manage such variables as morbidity, mortality, and the circulation of causal agents. As usage flexibility is a fundamental requirement, we developed VIGILA as a system readily adaptable to any level of the country's health organizations (national, provincial, or municipal). VIGILA permits the storage, validation, and statistical analysis of morbidity and mortality data, and it also allows the user to apply these features to causal agent information. These manipulations are all performed in the context of a specific transmissible disease. The stored information can be displayed in different types of statistical formats, such as calculated rates, accumulates and medians. The user can also design his/her own tables for display. In addition, the program offers graphics that depict the endemic forecast for a specific region and age group. Reliable forecasts based on temporal models of an epidemiological indicator are necessary for the prediction of the non-epidemic indicator and for the elaboration of an alert threshold. The endemic forecast or endemic channel is calculated by means of a modified version of R. Serfling's model [1] which adapts to data series with stationary characteristics. In this case, the model is fixed for the medical attention protocol and the circulation of agents of a specific transmissible disease. The parameters of the model are estimated by the least square method. The confidence limits are calculated with the T-Student distribution [2]. To enter information about a specific disease and level of health concern, the user must define the disease under analysis, the principal territory under surveillance and its dependencies, the causal agents of the disease, and the frequency with which the disease is reported. This system stores the number of cases (morbidity) and death (mortality) that occurred in the territories and age groups defined during entry. To facilitate the calculation of morbidity and mortality rates, information pertaining to the number of territory habitants and their age groups is also stored. The laboratory data includes the number of analyzed samples in the territories and age groups defined in the data entry, and the samples that were positive to the defined agents. Among the principal uses of the system are: calculation of cumulative cases, rates, and cumulative rates for the specific period of analysis, territory, and age group; comparison of these health indicators with the previous year's indicators or with the median of the previous years' indicators' calculation of the endemic forecast that permits the user to observe the epidemiological situation by territories and age groups; and the early detection of an increase in disease occurrence. The system also offers a geographical representation of the epidemiological situation in the territories, showing a map with the evaluation of each territory with respect to four possible risk factors. VIGILA is available in both DOS and WINDOWS 3.1 formats. This system allows the evaluation of the situation at a specific point in time in the analyzed territories, and may alert the infection control team to an epidemic early enough to allow implementation of control measures.

Computer Systems↗

PubMed1987

A survey of Census Bureau population projection methods.

"Population projections methods of the U.S. Census Bureau draw upon several different traditions of forecasting: demographic accounting, judgmental, time series, deterministic, and explanatory. This paper reviews each of the forecasting traditions in population projections, describes the U.S. Census Bureau's current methods for national and state population projections, and proposes new hybrid approaches such as demographic-time series methods for national fertility projections and economic-demographic methods for state migration projections. Throughout the article, possible parallels with forecasting in other disciplines are noted."

Americas↗

PubMed1989

Predictability of demographic variables in the short run.

In assessing the performance of population forecasts, it is useful to have a standard with which forecast errors can be compared. Univariate time series models may provide such a standard. Mean forecast errors of time series models indicate to what extent the movement of a variable could have been predicted from its own past. These errors show the degree of predictability that is attainable, at least in a given period. In this paper 3 time series methods (exponential smoothing, Box-Jenkins method, and structural time series models) are applied to Dutch data on births, deaths, marriages, immigrants, and emigrants. The variability of prediction errors between different periods is examined. The possibility that univariate predictions can be improved by using quarterly or monthly data instead of annual data is tested.

Demography↗

PubMed1992

The Victorian population projection framework.

"The Victorian Department of the Treasury has responsibility for preparation of demographic forecasts for use by state government departments and agencies. This paper provides a detailed description of the projection system and models developed by Treasury to produce population and household forecasts for the state, statistical divisions and Statistical Local Areas of Victoria [Australia]. Particular emphasis is given to use of a 'tops down' approach to integrate projections at different geographic levels, methods of reconciling forecasts of household growth with land supply and techniques used to project the inter-SLA migration flows in a multi-regional cohort-component framework."

Agriculture↗

PubMed1984

Integrated population and employment projections for national-regional planning in the Federal Republic of Germany.

"The concepts, methodological approach, assumptions and results of a long-term forecast for 88 federal planning regions in West Germany are presented and discussed. It is emphasized that population and employment projections for policy consultation purposes must be of an intermediate complexity in order to remain transparent and reconstructable. To facilitate the interpretation of the forecasting results, a typology of the planning regions along the dimension of forecasted labour market developments is presented." It is found that "rural peripheral regions with employment problems stemming mainly from demographic factors and old industrial regions with severe labour market imbalances caused by structural change are...the actual and future problem regions in West Germany."

Demography↗

PubMed1988

A modified logistic model applied to human populations.

"The use of the logistic curve for forecasting human populations [in the United Kingdom] considered by Leach is re-examined. A modification of the use of the logistic curve is suggested, which changes the emphasis from fitting a logistic trend to providing a forecast logistic trend. The assumption, used by Leach, that the variance of the additive disturbance term is constant is replaced by a more realistic supposition that the variance of the proportional disturbance is constant. The forecasting performance of the modified logistic model is shown to be superior to that of the model used by Leach." A reply by Leach (pp. 496-7) and a response by the author (p. 498) are included.

Developed Countries↗

PubMed1987

[The reliability of the expectation (not) to have a child within three years].

The author examines the reliability of fertility expectations in the Netherlands over a three-year period starting in 1982. The data are from the 1982 and 1985 Netherlands Fertility Surveys. "On the individual level the expectations of 86% of all women turned out to be consistent with the demographic behaviour in the following three years. Of the women who had expected to have a child 63% had had one. Of the women who had not expected to have a child 92% indeed did not.... On the aggregate level the forecast was reasonably accurate: 21% of all women had expected to have a child whereas 20% had had one. Obviously the forecast error is larger for some categories of women than for others: the most deviant are the cohabiting women who show a rather large overestimation. But generally speaking the results of this analysis are promising for the use of short-term birth expectations in population forecasts." (SUMMARY IN ENG)

Birth Rate↗

PubMed2005

The future of the HIV pandemic.

The emerging HIV epidemics in countries of Asia and Eastern Europe will contribute significantly to the future of the HIV pandemic. Forecasts of the scale of these epidemics are subject to massive uncertainty, however, mainly because of the sensitivity of predictions to small alterations in parameters that are difficult to estimate. In most of these countries, HIV is currently concentrated among vulnerable populations such as injecting drug users, sex workers and their clients, or men who have sex with men. This distribution suggests an alternative to disease forecasting based on the techniques of risk assessment routinely used by environmental epidemiologists. Exposure mapping, dose-response curves and the concept of acceptable risk are some of the tools that may be useful for HIV risk management. This approach is illustrated by a description of exposure in Indonesia and an assessment of currently accepted risk of death for different causes including HIV in the Russian Federation. Although inappropriate for forecasts of heterosexual HIV transmission, mathematical models are shown to be useful for making qualitative predictions about the relative importance of different behaviours for the spread of HIV over time and for interpreting observed trends in HIV prevalence from sentinel surveillance sites.

Adolescent↗

PubMed2000

Caring for the critically ill patient. Current and projected workforce requirements for care of the critically ill and patients with pulmonary disease: can we meet the requirements of an aging population?

CONTEXT: Two important areas of medicine, care of the critically ill and management of pulmonary disease, are likely to be influenced by the aging of the US population. OBJECTIVE: To estimate current and future requirements for adult critical care and pulmonary medicine physicians in the United States. DESIGN, SETTING, AND PARTICIPANTS: Analysis of existing population, patient, and hospital data sets and prospective, nationally representative surveys of intensive care unit (ICU) directors (n = 393) and critical care specialists (intensivists) and pulmonary specialists (pulmonologists) (n = 421), conducted from 1996 to 1999. MAIN OUTCOME MEASURES: Influence of patient, physician, regional, hospital, and payer characteristics on current practice patterns; forecasted future supply of and demand for specialist care through 2030. Separate models for critical care and pulmonary disease. Base-case projections with sensitivity analyses to estimate the impact of future changes in training and retirement, disease prevalence and management, and health care reform initiatives. RESULTS: In 1997, intensivists provided care to 36.8% of all ICU patients. Care in the ICU was provided more commonly by intensivists in regions with high managed care penetration. The current ratio of supply to demand is forecast to remain in rough equilibrium until 2007. Subsequently, demand will grow rapidly while supply will remain near constant, yielding a shortfall of specialist hours equal to 22% of demand by 2020 and 35% by 2030, primarily because of the aging of the US population. Sensitivity analyses suggest that the spread of current health care reform initiatives will either have no effect or worsen this shortfall. A shortfall of pulmonologist time will also occur before 2007 and increase to 35% by 2020 and 46% by 2030. CONCLUSIONS: We forecast that the proportion of care provided by intensivists and pulmonologists in the United States will decrease below current standards in less than 10 years. While current health care reform initiatives and modification of existing practice patterns may temporarily forestall this problem, most anticipated effects are minor in comparison with the growing disease burden created by the aging US population. JAMA. 2000;284:2762-2770.

Aged↗

PubMed1995

Trends in mortality from melanoma in Canada and prediction of future rates.

A long term increase in incidence of and mortality due to malignant melanoma has been observed in all well documented white populations. The major identified cause of melanoma is sun exposure. One would expect predictions of future atmospheric ozone depletion to lead to an increase in ultraviolet radiation (UVR) and in the effects of sun exposure. We consider age-period data for Canadian malignant malanoma mortality. We fit a multiplicative exponential/logistic (MEL) model to the data and extrapolate to AD 2010 hence yielding point estimates of future rates. We obtain total mortality forecasts by multiplying rates by population estimates. We present standard errors for forecasts. We forecast that melanoma will be a much larger burden on the health care system in the early years of the next century than it is at present. We obtain an age-cohort model by a simple transformation of the age-period model. Also, we obtain unconditional probabilities of death due to melanoma both for age-period and age-cohort models. We discuss the assumptions underlying the MEL model that suggest possible relationships between UVR and melanoma.

Adult↗

PubMed2000

Intracranial pressure processing with artificial neural networks: prediction of ICP trends.

It is well known that intracranial pressure (ICP) is influenced by an array of predictable and unpredictable factors, which gives rise to a signal heavily loaded with stochastic, i.e. random components. Hence, statistical modelling of this signal has proved to be of limited utility, in spite of the very sophisticated mathematical methods applied. In recent years, neural network algorithms (ANN), which are an alternative to statistical methods, have proved their effectiveness in the prediction of trends, as applied in a variety of medical and non-medical tasks. We therefore attempted to test the efficiency of neural models in the on-line prediction of ICP values, compare their effectiveness to statistically oriented algorithms and combine ANN methods with some newer signal processing algorithms, like wavelet decomposition. Prediction horizons of up to 5 minutes have been tested with various architectures of the neural predictor. For a 3 minute prediction horizon, a satisfactory accuracy of forecasting has been achieved with "plain" ANN, as expressed by the "average relative variance coefficient". This was measured by the ratio of the prediction error obtained, in relation to the error which would occur if a current value were taken as the forecasted one. The prediction quality with statistical autoregressive models has proved unsatisfactory, whilst the result obtained using the ANN model with the wavelet transform incorporated, performed significantly better than the ANN models alone. The prediction quality obtained with the ANN methodology seems to be satisfactory over a short time horizon, though no conclusion can be derived at this stage of the study, as to the clinical utility of this method. In particular, even with this methodology, it is not possible to forecast any sudden dehiscencies of the ICP signal with any practical reliability. From the point of view of modelling theory, such sharp deviations of the signal may be regarded as a "catastrophe". This implies the necessity for a different approach to the ICP signal analysis with the artificial intelligence methodology; one, that is more oriented towards the global properties of the signal.

Cerebral Hemorrhage↗

PubMedDate not supplied

The ratio of AIDS to non-AIDS Medicaid medical costs from 1992 to 2000.

Our research objective was to calculate and forecast the monthly increase in medical and prescription costs for Medicaid patients with acquired immunodeficiency syndrome (AIDS) and compare these values with costs for non-AIDS patients. A retrospective analysis of AIDS patients and a control group of Georgia Medicaid beneficiaries was conducted between January 1, 1988, and December 31, 1991. AIDS patients were defined using the Keyes algorithm of combinations of International Classification of Diseases, 9th Revision, Clinical Modification codes. The AIDS patient group was matched demographically to a group of non-AIDS patients. Data were adjusted to account for eligibility status, and the ratio of AIDS costs to non-AIDS costs was modeled with an econometric time series procedure. A total of 1966 AIDS patients were identified from 900,000 Medicaid recipients in the study period; 58.0% were male and 59.8% were black. Age was bimodal at < or = 1 year and 33 years. The best fit for the medical cost ratios produced a significant regression coefficient of .37. The initial ratio of AIDS to non-AIDS forecast was 4.25 in January 1992. The January 2000 forecast of this ratio increased to 42.56. This increase equates to an additional $8510.19 per AIDS patient-month for January 2000 in 1991 dollars. The outpatient prescription ratio for AIDS versus non-AIDS patients was not predictable. However, the greatest observed discrepancies were attributed to the expense for antihemophilia products. Overall, the most important finding was the accelerating medical costs for treating AIDS patients compared with costs for treating non-AIDS patients. These results may, in part, reflect additional costs for treating intravenous drug users and pediatric AIDS patients.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Strategies for dealing with solar particle events in missions beyond the magnetosphere.

For long duration missions beyond the magnetosphere, the hazards posed by solar particle events (SPE) require the development of new strategies to minimize both the radiation dose and the effects. Potential strategies include the development of improved short-term forecasting of SPE through better observations and research, consideration of HZE particles in real-time forecasting and monitoring, improved knowledge of the biological effects of the particles involved in SPE, and the development of methods for combining SPE forecasts with temporary shielding and chemical countermeasures. Evaluation of present capabilities and the identification of areas of further research to achieve the necessary capabilities are discussed.

Cosmic Radiation↗

PubMed2005

Time series modelling of global mean temperature for managerial decision-making.

Climate change has important implications for business and economic activity. Effective management of climate change impacts will depend on the availability of accurate and cost-effective forecasts. This paper uses univariate time series techniques to model the properties of a global mean temperature dataset in order to develop a parsimonious forecasting model for managerial decision-making over the short-term horizon. Although the model is estimated on global temperature data, the methodology could also be applied to temperature data at more localised levels. The statistical techniques include seasonal and non-seasonal unit root testing with and without structural breaks, as well as ARIMA and GARCH modelling. A forecasting evaluation shows that the chosen model performs well against rival models. The estimation results confirm the findings of a number of previous studies, namely that global mean temperatures increased significantly throughout the 20th century. The use of GARCH modelling also shows the presence of volatility clustering in the temperature data, and a positive association between volatility and global mean temperature.

Climate↗