Social Mobility

Absolute versus Relative Mobility

A common measurement of social mobility is tracking the income or occupation of individual families over time and evaluating the degree of mobility in absolute or relative terms. Absolute mobility refers to the inflation-adjusted change in a family's income over time, often measured as it crosses over a fixed standard such as the poverty line. Relative income mobility is typically measured in movement between quintiles (a distribution that has been divided into fifths). Most families experience some relative mobility, moving up or down one or more quintiles in mean income. Yet, the proportion of families to remain in the same quintile increased from about 35 percent in the 1970s to about 40 percent in 1990s. This indicates an increasingly less mobile class structure.

Opportunity and Structural Mobility

The degree of mobility is related to the rate of growth in an economy and the amount of opportunity the economy holds for individuals to move from one type of employment to another. Changing U.S. economic structures in the 20th century account for most of the documented social mobility. With increasing productivity resulting from technological improvements, living standards may improve from one generation to the next, though the class structure itself changes little. However, the growth of the economy resulted from the structural transition from agrarian to industrial, then to technology-based economies. This allowed for a great deal of upward intergenerational mobility, especially during the postwar period (1950s-1970s), as the occupational structure of the country changed. Yet, the changes in the relative class status from one generation to the next were modest. Few moved more than a few positions (up or down) within the class structure.

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