American society changed immensely since the late nineteenth century. The evolution from an industrial to a post-industrial economy confronted successive cohorts with markedly different work and life opportunities. All classes and social groups had to accommodate themselves to this structural transformation, although their strategies and ability to exploit new options differed. Our knowledge of social and economic change over the last century is extensive but fragmentary, offering little basis for consistent comparisons between places or over long periods of time. New statistical evidence provides the opportunity to redress this deficiency. An integrated database combining millions of census records from 1880 to 1990 reveals the effect of long-term economic transformations on individuals and families across the nation. The experience of women in the economy changed dramatically since 1880. The official record of female labor force growth is distorted, however. The gendered assumptions underlying occupation statistics necessitate a significant upward revision of published female work rates before 1940. The evidence also reveals a key change in family income-earning strategies in the twentieth century: married female paid labor went from being the last resort of needy families to a means of increasing family consumption. This transformation to paid labor outside the home, spearheaded by wives in lower white-collar families, was integral to women's increased power in American society. As better jobs became accessible to women, the social status derived from work increasingly spurred middle-class female employment. The changing pattern of male economic opportunity is best reflected in men's position within the occupational structure. Economic rewards to specific jobs remained stable, but the entire occupational structure shifted upward as white-collar work grew at the expense of agriculture and unskilled labor. Although the economy steadily generated more better-paid occupations, men's access to desirable jobs was persistently stratified by race, nativity, and age. With few exceptions, the evolution to higher-status jobs meant greater opportunities for each successive birth cohort. Immigrants were disadvantaged in the labor market, but their sons consistently secured work of equal status to the native-born. In contrast, blacks of both sexes continue to suffer lower attainment than their human capital would suggest.

Historians have long depended on occupational data to gauge social mobility, class position, and the status of groups. Occupational classification schemes have varied over time, but they have generally been consistent since most have been tied to the practices of the US Census Bureau. When income is considered in combination with occupation, the relative social status of men's occupations appears to have been very stable during the first half of the 20th century. While social and economic change during this period was quite dramatic, most of it was absorbed by redistributing people among occupations rather than movement in the relative standing of occupations.

Examines the Integrated Public Use Microdata Series census material project at the University of Minnesota. The project aims to provide a unified interface for researchers and to make the interface and data available on the World Wide Web.

Describes the process involved in creating the occupational codes for the 1850, 1880, and 1920 Public Use Microdata Samples (PUMS). PUMS are random samples of households taken from the US decennial censuses and coded into computer format for use by historians and social scientists. Much of the work for the 1850, 1880, and 1920 PUMS has been done by the Social History Research Laboratory at the University of Minnesota. The process for encoding occupational data was especially difficult because each census recorded such information differently. The laboratory solved this problem by using a common classification scheme and creating a data dictionary to translate the manuscript census information into codes. Additionally, they used occupational groupings of the 1950 census to create a supplementary coding scheme that provided more detailed information. In many instances the PUMS clearly demonstrate that the Census Office's shoddy procedures often led to dramatic undercounts of many occupational categories, particularly female domestic servants.

Discusses the process by which the Social History Research Laboratory at the University of Minnesota designed the Integrated Public Use Microdata Series (IPUMS). The Public Use Microdata Samples (PUMS) consist of random selections of information that have been taken from the US decennial censuses since 1850. These samples are useful sources of information for the decade from which they were taken, but because each census records data differently, much of the information is incompatible with other censuses. The Social History Research Laboratory has converted these PUMS into an integrated form called IPUMS. By designing common coding systems for such items as household composition, familial relationships, occupations, and geographical location, the IPUMS allows a researcher to chart social changes over time. Versions of the IPUMS data series were released in 1993 and 1994, and the final version will be released in November 1995 by the National Archives. A three-volume set will also be released that provides detailed documentation for the data series and user information.

Public Use Microdata Samples (PUMS) are random samples taken from the decennial censuses since 1850. Because PUMS use the coding systems from the censuses from which they are taken, comparison between PUMS is often impossible. For this reason the Social History Research Laboratory of the University of Minnesota developed the Integrated Public Use Microdata Series (IPUMS), which uses compatibility codes that allow such comparisons to be made. To create IPUMS codes for occupation and income, the 1950 census and its occupational grouping scheme was adopted. PUMS taken from all other censuses were recoded according to this scheme, which now allows for comparison over time. A similar IPUMS coding system was done so that median income could be compared between various PUMS.

Uses the most important primary source of the past century for economic and social historians, the public use samples of the manuscript census, to devise empirical measurements of the Marxist idea of class. Marxist definitions of class have two elements. Class is relational, that is, the patterns of life and social relations take place among people, not against an abstract index of stratification. In addition, class is understood to take place within the sphere of production and includes how people relate to the ownership of the means of production. Although class and its understanding is central to the Marxist analysis of capitalism, there have been very few efforts by Marxist social scientists to attempt precise measurement of their organizing idea. The author analyzed the public use samples from 1910 and 1940 through 1980 with these Marxist definitions in mind. The results show that it is possible to specify with accuracy the changing fortunes of the American bourgeoisie, petite bourgeoisie, and proletariat. Three findings stand out for 20th-century American class relations. First, the percentage of the that is proletarian has been quite consistent, averaging about 70% from 1910 through 1970, and dropping to 61% in 1980. Second, the major change in class membership has been the rise of a professional managerial class, which as of 1980 constituted 28% of the population. Third, the income gap between the proletarians and bourgeoisie increased considerably after World War II and up through 1980, indeed well before the more recent additional changes in income inequality.