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Conventional methods of presenting long-term changes in the age compositions of general populations graphically make use of bar graphs and population pyramids. In the graphs the heights of the bars equal 100 percent subdivided by desired age-groups, the age-group proportions changing over a long-term period. In the population pyramid the sum of the percentages of the age and sex groups also equals 100 percent, thereby enabling one to compare age and sex compositions of different populations at a glance and to note roughly the "dative proportions of young and aged, males and females. For general purposes these two methods are useful. However, as in all scientific work, there are constant attempts to refine earlier methods of analysis in order to combine a host of factors into one single index or measure which will have the attributes of greater precision and ease of communication to others. Accordingly, the purpose of this paper is to suggest a single index for a measure of changing age distributions in general populations. For certain purposes, this index can be regarded as a refinement of the bar graph and the populations pyramid.

This article focuses on the racial aspect of the differential fertility in California in 1930. In California, problems connected with the racial differential are particularly significant. The racial minorities are numerically important. They form rather distinct cultural groups and are, in the main, clearly set off from the majority by skin color. Many of them are denied the privilege of citizenship, and miscegenation is either prohibited by law or enforced by custom. And they are markedly differentiated from the white majority in another respect: they are not only guaranteeing the stability of their numbers in the future but were, in 1930, reproducing at a rate so high that they might be expected, when their age distribution becomes stabilized, to double in numbers in little more than a generation, while the reproductive level of the whites was, under the same conditions, at so low a level that a decline in numbers by about a third per generation might have been expected. The aim of this paper is to uncover some of the factors underlying this differential.

Over the last quarter of a century, the educational selectivity of interregional migration has varied somewhat among time periods, age groups, and interregional streams: but there have been a number of persistent tendencies, particularly with respect to migration to and from the South. In general, interregional migration tends to be selective of the better educated. Within age, sex, and color groups, interregional migrants tend to be better educated than nonmigrants at their origin or destination. The net effect of this selectivity upon the educational distribution of the population in the regions has been rather slight, however. [ABSTRACT FROM AUTHOR]

This study investigates the decline of fertility in the Southern Appalachian Mountain Region. Fertility rates of the white population were computed for each of the 190 counties included in the region for the years 1930, 1940, 1950, and 1960. Four measures of fertility were used: (1) the crude birth rate, (2) the child-woman ratio, (3) the general fertility rate, and (4) the general fertility rate indirectly standardized to the age distribution of U.S. white women 15 to 44 years of age in 1950. The hypothesis was supported that the recent decline in fertility was associated with net out-migration, which is highly selective of young adults. Net out-migration did not, however, account for the greater part of the decline. The ecological pattern of declining fertility showed the lowest rates to be in the metropolitan areas and in the more prosperous valley regions, while highest rates continued in the highland areas. [ABSTRACT FROM AUTHOR]

The theory of the demographic transition is proposed as a theory with considerable generality. A systematic statement of the theory is suggested including not only trends of birth and death rates but also concomitant changes in form and size of family, differential fertility, differential mortality, sex ratio, age composition, occupational distribution, and residential patterns. [ABSTRACT FROM AUTHOR]

This article presents a comparative study of age distributions of populations of major cities in the United States. The analysis involves all of the cities, 113 in number, having 95,000 or more inhabitants at the time of the 1950 Census. Several studies were done, over the years, to determine definitely that the proportions of young children, adolescents, young adults, those in the prime of life, persons nearing the retirement ages, and of the aged differ sharply from one city to another. For the purpose of comparative analysis of age distribution patterns, a simple charts based on index numbers-based methodology is used which show for each five-year age group the extent to which each city contained in 1950 more or less than its pro rata share of the national total. After the indexes had been computed showing the extent to which in 1950 each of the 113 major cities in the United States contained more or less than its pro rata share of each age group, from 0-4, to 75 and over, the data for each were charted for clear interpretation of data. Three major factors, affecting age profiles, were identified which are: fertility, mortality, and migration.