A Sudden Transition: Household Changes for Middle Aged U.S. Women in the Twentieth Century.

Between 1900 and 1990, the percentage of U.S. white women aged 40-69 living with a child of their own fell from 63% to 27%, with three fourths of that change occurring between 1940 and 1960. Historical census data from the Integrated Public Use Microdata Series and longitudinal data from the Panel Study of Income Dynamics allow an historical and contemporary examination of co-residence patterns among these women. Analysis reveals three eras: a system of co-residence in the early twentieth century, a sudden transition toward separate households at mid century, and the maintenance of that separate household system thereafter. The scholarly literature features cultural, demographic, and economic explanations for the long-term decline in co-residence, but has given little attention to the rapid mid-century shift. Analysis of IPUMS data confirms the long-term effects of declines in mortality and fertility, and concomitant declines in the age of mothers at last birth, but also points to a sharp drop in the age of children at marriage in the mid-twentieth century. These factors raised the potential for the formation of separate households, but this historical era was also a propitious one for separation: income gains for young workers were unprecedented, the labor force participation of married women rose, and immigration fell. Analysis of PSID data from 1968 to 2009 confirms the salience of children's socioeconomic circumstances-particularly their marriage and employment prospects but also the increasing availability of higher education-in maintaining the separate household system. While the data analyzed allow only inferences about cultural factors, the resiliency of the new household system, even in periods of economic decline, suggests that it is now likely buttressed by strong normative views.