Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Estimation Technics”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 991 records · Page 55Linked to original sources
PubMed1981

On the persistence of U.S. migration rates in the 20th century.

The persistence or inertia of net migration rates in the United States during the twentieth century is measured. A set of basic migration data for states, counties, and state economic areas is described, and manipulations of these data are discussed. "The manipulated data are [then] analyzed graphically and by regression. The report concludes with a few remarks on the use of demographic extrapolations for planning and policy purposes."

Americas↗
PubMed1983

A regional analysis of illegal aliens.

"This paper combines inferences about the unknown population of illegal aliens with apprehension data and economic indicators to estimate the separate effects of enforcement activity and economic changes on the stock of illegal aliens in the United States. This method offers a substantial improvement over previous empirical estimates based solely on apprehension data."

Americas↗
PubMed1996

Using moving-industry data to depict U.S. migration patterns.

"Migration analysis is hindered by the lack of up-to-date migration data. This paper examines the feasibility of using information from the American Moving Conference (AMC), the trade organization of the moving industry, to develop timely estimates of gross in- and out-migration and net migration rates at the state level. When adjusted for the spatially varying size of migrant households and the spatially varying market share of the professional moving industry, the number of AMC inbound and outbound shipments provides useful, but slightly imperfect, estimates of migration in 1990 and 1991. Viewed as a time series, adjusted AMC shipment data accurately reveal the major migration stories of the last decade. AMC-based estimates for 1992, 1993, and 1994 provide a picture of state in- and out-migration for years in which official data are not yet available."

Americas↗
PubMed1981

Forecasting Australian marriage rates.

"The paper discusses the problem of modelling demographic variables for the purpose of forecasting. Two empirical model selection procedures are applied to suggest final form forecasting equations for Australian marriage rates. The suggested models are then assessed by comparing their post-sample forecast performance with that of univariate ARMA-type models of marriage rates which are regarded as approximations to marriage rate final equation models. In this instance the ARMA models are preferred for forecasting purposes. The properties of the ARMA model forecasts are then examined and the modelling strategy is contrasted with the regression method used by Withers."

Australia↗
PubMed1987

Errors in estimates of smoking-related deaths derived from nonsmoker mortality.

A number of recent analyses have computed present and future costs associated with a risk by estimating what would happen if the risk were absent. Two sources of bias are associated with this approach: (1) differences in confounding factors between present risk avoiders and risk takers, and (2) the difficulty of selecting an unbiased sample of risk avoiders. A staff memo from the Office of Technology Assessment used this approach to estimate mortality due to smoking. Numbers of deaths and age at death distributions of U.S. smokers and nonsmokers for all causes, all cancers, lung cancers, heart disease, and cerebrovascular lesions are used to assess the accuracy of these estimates. Large errors in the OTA estimates are found. Conditions are discussed that might help reduce errors from this approach.

Humans↗
PubMed1987

Modelling interprovincial migration using entropy-maximizing methods.

"The concern in this paper is with the prediction of population movements through the mathematical modelling of migration. In particular, the emphasis is on the testing of one of the most basic of a family of models of spatial interaction that have been developed in an information theoretic context in geography. Of special interest with this basic, totally constrained interaction model is the role of the distance variable in population migration and the extent to which it can be employed to predict Canadian interprovincial population migration flows."

Americas↗
PubMed1995

The simulation of urban system dynamics in Atlantic Canada, 1951-1991.

"A dynamic urban model is used to study the post-war evolution of the Atlantic Canada urban system. The computer-based simulation model is calibrated for the period 1951-86 and then employed to predict the 1991 population of each CMA and CA within the system. The simulation results show that, to a large extent, the evolution of the system can be understood in terms of endogenous system dynamics rather than exogenous events. Specifically, competition among the cities of the region is a significant factor in the urban system evolution. The high degree of abstraction of the model means that data requirements for application are minimal, and the calibration procedure is relatively simple. The successful predictions show that the model can yield useful results in spite of its simplicity." (SUMMARY IN FRE)

Americas↗
PubMed1988

Seropositivity for HIV and the development of AIDS or AIDS related condition: three year follow up of the San Francisco General Hospital cohort.

The three year actuarial progression rate to the acquired immune deficiency syndrome (AIDS) in a cohort of men in San Francisco who were seropositive for the human immunodeficiency virus (HIV) was 22%. An additional 26 (19%) developed AIDS related conditions. Beta 2 Microglobulin concentration, packed cell volume, HIV p24 antigenaemia, and the proportion and number of T4 lymphocytes each independently predicted progression to AIDS. Beta 2 Microglobulin was the most powerful predictor. The 111 subjects tested who were normal by all predictors (40%) had a three year progression of 7%, and the 68 subjects who were abnormal by two or more predictors (24%) had a progression rate of 57%. Two thirds of all men who progressed to AIDS were in the last group. The median T4 lymphocyte count in subjects who did not progress to AIDS fell from 626 x 10(6) to 327 x 10(6)/l. HIV p24 antigenaemia developed in 7% of the subjects per year. The proportion who were abnormal by two or more predictive variables rose to 41%. At three years an estimated two thirds of the seropositive subjects showed clinical AIDS, an AIDS related condition, or laboratory results that were highly predictive of AIDS. It is concluded from the observed rates and the distribution of predictive variables at three years that half of the men who were seropositive for HIV will develop AIDS by six years after the start of the study, and three quarters will develop AIDS or an AIDS related condition.

AIDS-Related Complex↗
PubMed1992

Risk of HIV infection from transfusion with blood negative for HIV antibody in a west African city.

OBJECTIVE: To estimate the risk of infection with HIV (HIV 1 or HIV 2, or both) from transfusion of a screened unit of blood in a high prevalence area in west Africa. DESIGN: Retrospective cohort study for January-July 1991. SETTING: National Blood Transfusion Centre, Abidjan, Côte d'Ivoire. SUBJECTS: Repeat donors (5831 units of blood) and first time donors (5076 units) in the first five months of 1991. MAIN OUTCOME MEASURES: Prevalence and estimated incidence of HIV infection in repeat and first time donors; estimated rate of potentially infected, HIV antibody negative units; and rate of (false negative) potentially infected units assuming a laboratory test sensitivity of 99%. RESULTS: Overall HIV prevalence was 11.0% in first time donors and 2.1% in repeat donors. In the first seven months of 1991, 29 HIV antibody positive (27 HIV 1, 1 HIV 2, 1 dually reactive) donors with a seronegative unit of blood earlier in the year were identified; 26 had donated blood eight weeks or less before their estimated dates of seroconversion and may have been infectious (minimum rate 26/5831 (4.5/1000 potentially infected units)). Estimated incidence of infection in repeat donors was 1.2-2.5%. Laboratory test insensitivity would result in an estimated 1.1/1000 false negative units from first time donors and 0.2/1000 units from regular donors. The overall rate of potentially infected units (all donors, seroconversions, and errors) was estimated at 5.4-10.6/1000. CONCLUSIONS: The risk of HIV infection from a single unit of blood remains substantial (5.4-10.6/1000 units). To prevent infection from blood transfusion in areas of high incidence and prevalence of HIV all but absolutely essential transfusions should be avoided, and donors with low incidence of HIV infection should be selected.

Blood Donors↗
PubMed1978

Economic analysis of body computed tomography units including data on utilization.

All operating body computed tomography installations in the United States were surveyed in May 1977; data were obtained from 74 of 118 installations. Utilization and economic data from this survey are compared to similar data from January 1976. Scheduling delay data indicate that computed tomography availability is closer to meeting the clinical demand for CT studies than in January 1976; however, CT demand (as indicated by scheduling delay) is rising at installations with greater than 5 months BCT experience. The estimated annual technical cost of BCT is $359,000--$392,000 with a patient volume of 25--50 patients per week and is higher than the current net technical revenue.

Costs and Cost Analysis↗
PubMed2004

The Glasgow Children's Benefit Inventory: a new instrument for assessing health-related benefit after an intervention.

Most health-related quality-of-life measures make an assessment at a single point in time. Comparing results before and after an intervention is often difficult, because the difference measured is usually small compared with the variation between individuals. A retrospectively applied measure specifically worded to assess benefit would be very useful for clinical research. Such a measure exists for adults. We aimed to develop a similar measure for children. We chose potential items after reviewing existing health-related quality-of-life measures, published literature, and parental interviews. A draft questionnaire was given to a group of parents and modified. The resulting Glasgow Children's Benefit Inventory (GCBI) comprised 24 questions on the consequences of a specified intervention on various aspects of the child's day-to-day life, without reference to any specific symptoms, and was worded to apply to children of any age. The questionnaire was mailed to the parents of all 1,777 children who had undergone tonsillectomy or ventilation tube insertion at one hospital during the period January 1998 to December 2001. There were 670 questionnaires returned. The GCBI scores correlated well with parental satisfaction with surgery and with estimates of technical success (residual sore throats, reported hearing impairment, ear infections). The questionnaire had high internal consistency. Factor analysis showed 4 dimensions in the pattern of responses relating to emotion, physical health, learning, and vitality. The GCBI is a means to retrospectively assess benefit after an intervention in children, and we have shown initial evidence of reliability and validity. Although not restricted to any branch of pediatric medicine, it is eminently suitable for use in pediatric otolaryngology.

Adolescent↗