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At least 19 recordsLinked to original sources
PubMed1975

Stouffer's model of migration: a comparison of interstate and metropolitan flows.

The objectives of this paper are (1) to evaluate the accuracy of the intervening opportunities-competing migrants hypothesis (Stouffer, 1960) in estimating 1955-1960 interstate migration streams in the United States and (2) to compare the results with those obtained by Galle and Taeuber (1966) for metropolitan migration. Our results strongly confirm Stouffer's hypothesis and yield parameter estimates highly comparable to those obtained for metropolitan migration, except that competing migrants exert a stronger influence than intervening opportunities in interstate migration. Our study is based on 2,256 interstate migration flows in the continental United States, whereas Stouffer's intercity study and Galle and Taeuber's metropolitan study were each based on 116 migration flows. Our results indicate that Stouffer's theory holds for different levels of aggregation with remarkable consistency. Several theoretical models of the migration process are more compatible with Stouffer's original 1940 formulation of intervening opportunities than his 1960 reformulation. Estimates for interstate data indicate that the 1940 definition provides slightly better results. For both these reasons, it would seem that the 1940 formulation should be given serious consideration in future tests of Stouffer's hypothesis.

Geography↗
PubMed1978

[Population structure and consaguinity in Dota, Costa Rica, 1888-1962].

A study of consanguinity and population structure was carried out in a sample of 498 consanguineous (MC) and 570 non-consanguineous matings (MNC) in the Parrish of Dota, Costa Rica, during a period of 75 years. The inbreeding coefficient (F) shows fluctuations in time (476 to 194 x 10(-5) with an increase from 1888 to 1917, followed by a decrease in the last years but remains high in nonmigrant marriages. There is a high frequency of unions among second cousins. The endogamy percentage is high, greater in MC (80%) than in MNC (61%). Exogamy tends to diminish with time among both types of union. Effects of age distributions in the groups was not found. Marital and migrational distances are short and tend to become shorter in the final periods. There is a positive correlation (r = 0.71; p less than 0.05) between these distances in MC but not in MNC; distances are shorter in MC. Immigration is minimal and reduced to short distances. Post-marital movement is intense (37%) and involves greater distances. Emigratory behavior is identical in MC and MNC.

Consanguinity↗
PubMed1991

Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.

Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.

Birth Rate↗
PubMedDate not supplied

Marital distance and child variability.

The effects of marital distance on the mean and variance of child stature and weight were investigated using the British National Child Development Study data. Children of large marital distance unions had mean values as predicted from mid-parent values and did not exhibit a hybrid vigour effect. However, they did show reduced levels of variability and this effect was most marked at 16 years, although it was also present at 7 and 11 years of age. These results are discussed in terms of large marital distance being associated with high heterozygosity levels, because of geographic variation in gene frequencies.

Adolescent↗
PubMed1977

Isolation by distance in human populations.

Malécot's theory of isolation by distance under 'continuous' migration is shown to fit acceptably to various human populations. Although it provides a less complete and reliable prediction of population structure than migration matrices, it is applicable to a greater range of structures and data.

Genetics, Population↗
PubMed1988

A genetic history of Italy.

Statistical techniques for displaying the geographical distribution of many genes in few synthetic images have been used to represent the various patterns of gene frequencies in Europe and in the world (Menozzi et al. 1978; Piazza et al. 1981 a). It has also been shown that such synthetic displays are particularly useful in detecting clines of genetic differentiation associated with movements of populations like those accompanying the Neolithic expansion of farmers from the Near East or, in more recent times, the putative diffusion of Indo-European-speaking populations (Ammerman & Cavalli-Sforza, 1984; Gimbutas, 1973). In this paper we use the same combination of statistical and graphical techniques to study the genetic structure of Italy, a European country whose unity of people and cultures was quite a recent event. The possibility of studying genetic differentiation in a small geographical area is tested and trends of genetic differences are tentatively interpreted in terms of historic and linguistic knowledge. The few demographic pieces of information taken from historical sources and compared with linguistic records support the hypothesis that the genetic structure of Italy still reflects the ethnic stratification of pre-Roman times.

Blood Group Antigens↗
PubMedDate not supplied

[The correlation of the indices of animal longevity and mortality in stationary populations with a constant rate of mortality].

Equations have been derived on the basis of general ratios of the numbers of different age groups of animals that allow to estimate the mortality coefficient in populations with stationary age structure and intensity of mortality that does not depend on age at their continuous and discontinuous replenishing by frequency of occurrence of individuals of the maximal age. The proposed method of estimation of mortality has been tested on models with different numbers of animals and age classes. The equation gives a non-biased estimate of mortality coefficient for populations with discontinuous replenishing with young individuals at very small sample sizes (less than 10 individuals).

Aging↗
PubMedDate not supplied

Florence Nightingale: statistician and consultant epidemiologist.

Florence Nightingale became a legend in her own lifetime and the image of the lady with the lamp still influences public thinking about the practice of nursing and its practitioners. Like many legends, her story has been adapted to suit changing circumstances and purposes. One could speculate why it is that particular aspects have come into greater prominence at particular times in history. This article explores a less-known aspect of her work, her expertise and use of statistics and epidemiology. And it illustrates how that expertise was called upon to address a major health problem in New Zealand in 1860.

Data Collection↗
PubMed1986

Examination of the generalized age distribution.

The formula for the age distribution and other relationships that follow from it for any (non-stable) population presented by Preston and Coale are significant contributions to demography. The formulas summarize the relationships among various demographic measures precisely, and are formally analogous to the relationships that hold for stable populations. The significance of these formulas cannot be overstated; they allow us to understand clearly the relationships among demographic measures in any arbitrary population. However, when it comes to using them for estimating demographic measures when census data are defective, the method of estimation is still affected by defective data. The reason is that the series of age-specific growth rates reflects the observed census age distributions exactly so that any defects in the census data are summarized in the growth rates. This paper begins with the formulation of the discrete version of the "new synthesis" developed by Preston and Coale. With the discrete formulation, the three kinds of errors introduced when the continuous time formulas are applied to real data can be avoided. Then it is pointed out that when two accurate census data are available, the Preston-Coale procedure of "estimating" the age distribution at the second census is equivalent to checking the identity of the age distribution formula. Also "estimating" mortality by the procedure of Preston-Coale is shown to be equivalent to obtaining mortality directly from intercensal survival rates. That the procedure which involves the age-specific growth rates is equivalent to those that involve the intercensal survival rates may have escaped notice because there are no a priori constraints for patterns of age-specific growth rates to follow. The irregularity in growth rates due to defective data are not distinguishable from true irregularity that exists in the population, contrary to the well-known regularity in the pattern of survival rates in human populations.

Actuarial Analysis↗