Biomedical subjects

P A Rogerson

Publications and source records attributed to P A Rogerson.

13 recordsLinked to original sources

PubMed1998

The dynamics of neighborhood age composition.

"In this paper we investigate the changing demography of [U.S.] neighborhoods. We focus upon the dynamics of the age structure of neighborhoods, paying particular attention to the roles of (a) the magnitude of mobility and (b) the age composition of in-migrants and out-migrants. A model for studying the changing age composition of neighborhoods is developed, and alternative scenarios characterized by the nature of in-movement and out-movement are examined to make statements about the age of householders in neighborhoods. We find that high rates of mobility may serve to bring about a relatively youthful equilibrium age structure quite rapidly, whereas low rates lead to a higher mean age and to damped harmonic fluctuations both in the mean age of householders and in the magnitude of the age heterogeneity of the neighborhood. In addition, we compare the evolutions of age structure in neighborhoods with age patterns of in-movement and out-movement that could typify areas of renters and areas of homeowners."

Age Distribution↗

PubMed1997

Surveillance systems for monitoring the development of spatial patterns.

Statistical methods concerned with the identification of temporal patterns may be classified into those that examine retrospectively a set of observations, and those that constitute surveillance systems that monitor changes as new observations become available. A similar distinction applies to the identification of geographical patterns in spatial data. There has been a notable lack of attention given to the surveillance of spatial pattern. This paper concerns development of a cumulative sum statistic and procedure for the monitoring of spatial pattern, and its application to both simulated data and to data on Burkitt's lymphoma in Uganda.

Adolescent↗

PubMed1996

A generalization of Hewitt's test for seasonality.

BACKGROUND: Hewitt's statistic for seasonality in monthly data is the maximal rank sum among all possible rank sums derived using consecutive 6-month periods. In this paper, Hewitt's test is extended to include those instances where 3, 4 or 5-month pulses or periods of raised incidence are hypothesized. METHODS: Monte Carlo methods are used to drive the approximate distribution of the test statistic under the null hypothesis, when the length of the hypothesized period is k = 3, 4, or 5. A combinatorial method is used to derive exact levels for the test statistic. The test is applied to monthly data on adolescent suicide. Finally, the power of the test is compared with the chi2 statistic using Monte Carlo simulation. RESULTS: The distribution of the test statistic was found and used to test the null hypothesis of no seasonal variation in monthly adolescent suicides, using a period of k = 3 months. The null hypothesis was rejected, indicating seasonality in the data. Monte Carlo simulations show the test statistic to be more powerful than the chi2 statistic when sample sizes are small. CONCLUSIONS: This generalization of Hewitt's test should be most useful in those instances where the researcher wishes to carry out a quick and simple test of the null hypothesis of no seasonality against the alternative of a predetermined 3, 4, or 5 month period of raised incidence. When there is no a priori hypothesis about the appropriate length of period.

Epidemiologic Methods↗

PubMed1996

Geographic perspectives on elderly population growth.

"The proportion of a region's population that is elderly may change over time for many different reasons. The proportion may grow because of the net in-migration of elderly individuals, or it may grow because of the net out-migration of nonelderly residents. Furthermore, the proportion may grow if the number of nonmovers in the 'pre-elderly' cohort is relatively high. This paper discusses in detail the ways in which this proportion may change over time. This is complemented by a state-level empirical study of elderly population growth in the United States during the late 1980s. The spatial pattern of the rate of new entry into the elderly cohort among nonmovers is found to be particularly influential in determining changes in the proportion of a state's population that is elderly."

Adult↗

PubMed1994

On the relationship between handedness and season of birth for men.

A sample of 8,929 male baseball players and a sample of 2,234 males from the U.S. National Health and Nutrition Examination Survey are used to assess the relation between handedness and season of birth. The results, when coupled with a further examination of the 1991 data of Dellatolas, Curt, and Lellouch, lead to the conclusion that those born during the spring and early summer are more likely to be left-handed than are those born during the fall and winter.

Adolescent↗

PubMed1990

Buffon's needle and the estimation of migration distances.

"A procedure is suggested for estimating migration distances from data on the proportion of migrants crossing regional boundaries. The method makes use of Buffon's needle, a problem in geometrical probability from the eighteenth century.... The procedure is described for various scenarios that differ in their assumptions about region shape, the spatial distribution of population, and the distribution of migration distances. An application to migration distances in the United States is given, and additional attention is given to the estimation of intraregional migration distances." (SUMMARY IN FRE)

Americas↗

PubMed1986

Dynamic flow modeling with interregional dependency effects: an application to structural change in the U.S. migration system.

Causative matrix methods can be used to project levels of population change, to monitor changing migration trends, and to aid in forecasting movement during periods of consolidation and dissipation. They are appealing because they provide measures of the changing strengths of all interregional dependency effects. Separate competing destinations and competing origins perspectives on temporal change can be obtained. The column sums and the eigenvalues provide useful aggregate gauges of the relative strengths of regional shifts. Patterns of U.S. interregional migration from 1935 to 1982 are examined using the causative matrix approach. Trends in the gross migration streams underlying the dramatic increase in core-periphery net migration taking place in the 1970s are examined, as is a more recent shift in the major source area of core region net outflow.

Emigration and Immigration↗

PubMed1985

Economic-demographic models for forecasting interregional migration.

"A class of spatial economic-demographic forecasting models is proposed. The models combine elements of traditional Markov and economic gravity models. A base-period probability structure is modified by the changing relative distribution of economic opportunity. Estimation issues are addressed, and an empirical application to US interstate migration during the late 1970s is described. It is contended that the framework represents a merger of past demographic and economic modeling traditions in a spatial interaction framework."

Americas↗

PubMed1985

Forecasting interstate migration with limited data: a demographic-economic approach.

"The limitations of available migration data preclude a time-series approach of modeling interstate migration [in the United States]. The method presented here combines aspects of the demographic and economic approaches to forecasting migration in a manner compatible with existing data. Migration rates are modeled to change in response to changes in economic conditions. When applied to resently constructed data on migration based on income tax returns and then compared to standard demographic projections, the demographic-economic approach has a 20% lower total error in forecasting net migration by state for cohorts of labor-force age."

Americas↗

PubMed1984

New directions in the modelling of interregional migration.

"This paper suggests two new approaches to modeling job-related migration. Both approaches are designed to simultaneously capture the inertia of past flows and information pertaining to economic conditions. One approach makes use of the incremental form of the logit model, and the other models the job application and competition process. Both techniques are illustrated using interregional migration flow data for the United States, and the results are compared with other migration models."

Americas↗

PubMedDate not supplied

The geography of elderly minority populations in the United States.

"Because minority populations often have greater needs for health care and fewer resources to pay for it, it is important to assess the demand for services. This paper takes an initial step in that direction by focusing upon the geographic distribution of elderly minority populations in the United States. The study is carried out at several spatial scales, and it is concluded that elderly minority populations tend to be even more segregated than their non-elderly counterparts."

Adult↗

PubMedDate not supplied

On the relationship between handedness and longevity.

During the past five years, there have been numerous studies of the relationship between handedness and longevity. In this report, I review previous contributions and use methods of survival analysis on a set of 4,448 males to determine the strength of the relationship between handedness and longevity. The results indicate that left-handers have small, yet significant, declines in survival probabilities between the ages of 65 and 85.

Adolescent↗

PubMedDate not supplied

The effects of sex preselection on the sex ratio of families.

Advances in the potential for couples to predetermine the sex of their children will have significant consequences for many aspects of society. Among the likely demographic impacts are changes in both population size and the sex ratio. The aim of this article is to assess the effects of sex preselection on the sex ratio of families. The expected family sex ratio is derived and characterized for couples with particular preferences for the sex composition of their families. When couples desire k children of one sex and none of the other, the proportion of children in the completed family that are of the desired sex falls with increasing k. Constraints on total family size further reduce this proportion. When couples have a desire for a balanced composition of one boy and one girl, and when they have a preference for, say, a boy to be born first, they can expect a proportion of boys in the family that at first rises, and then falls, as sex preselection methods improve.

Family↗