Journal Issue: Opportunity in America Volume 16 Number 2 Fall 2006
Most Americans think it unfair when things they cannot control limit their chances to succeed in life. Particularly un-American is the notion that circumstances of birth set life on a course that may be hard to alter through one's own efforts. So, rags-to-riches stories are popular, and crowds cheer for the underdog. Academic research on social mobility goes beyond the stories and the drama to quantify the link between circumstances of birth and economic success, both for the population as a whole and for important and interesting groups within it. Sociologists and economists put numbers to patterns by comparing the social and economic success of Americans with an absolute standard that is completely free of traces of birth and with a relative standard that is based on recent experience or the current experience of other countries. On the absolute standard, Americans' occupations and incomes are tied much more closely to their parents' occupations and incomes than they would be in a world where circumstances of birth were irrelevant for adult success.1 On the relative scale, ties between people's current occupations and incomes and those of their parents are about what they have been over the past twenty-five years, but substantially weaker than they were in the early 1960s.2
Social mobility from one generation to the next is the difference between a person's current income, wealth, or occupation and that of the family that raised her.3 An opportunity structure promotes social mobility if it allows people to escape poverty while limiting the degree to which those who grow up in privileged homes get advantages throughout their lives. Growth promotes mobility, too, by raising everyone, regardless of background, above the level of that background. In this article we will focus most on the opportunity structure because scholars have written more about it. But it is important to keep in mind how important growth can be. Nearly everyone who grew up in the Great Depression experienced substantial upward mobility in adulthood. It was not that America was more equitable when the children of the Great Depression grew up than it was before or has been since; it was that the nation recovered from its economic collapse and therefore most people were much better off. Social mobility should not be confused with inequality, which refers to differences among people in wealth, income, and occupational status at any point in time. Social mobility would not matter in a society in which there was no inequality. Parents would have no advantages to bequeath to their children, and no one would care where they ended up. But when inequality is great, social mobility matters a lot. The advantages of rising to the top are large, and the consequences of remaining stuck at the bottom are much more serious.
Social mobility is high if the opportunity structure is open—that is, if the barriers and advantages associated with a person's background are few. But openness of that sort is not the only way to spur intergenerational mobility. Mobility is also high if growth is strong and widespread enough to make everyone better off. The opportunity structure, in the form of barriers and advantages, is symmetrical in the sense that in the absence of growth, removing a barrier that might block a person who starts low also implies removing an advantage from a person who starts high. Growth, on the other hand, can—in President John F. Kennedy's famous phrase—lift all boats. If growth is widespread, it creates new opportunities that can lift a person who starts low without knocking down a person who starts high. But slow growth reduces social mobility, as does a closed opportunity structure.4
Growing inequality does not necessarily increase or decrease the prevalence of social mobility, but it does increase the difference between the upwardly mobile and the downwardly mobile. When inequality increases, extreme incomes, occupations, and amounts of wealth (high and low) become more prevalent, and fewer people occupy the middle of the distribution. So an upwardly mobile person has farther to rise and a downwardly mobile person has farther to fall in a more unequal society. Also (and this is a little less intuitive) an increase in inequality over a person's lifetime increases the probability that someone who starts life in extreme privilege will stay there and (simultaneously) increases the probability that someone whose parents were poor will also be poor. Those increases in immobility are offset, though, by a decrease in the probability that someone whose parents were about average will end up near the average (because rising inequality eliminates positions near the average). The increased immobility at the extremes and mobility in the center do not imply a stronger or weaker correlation between circumstances of birth and adulthood; they follow from the definition of inequality—more extreme outcomes, fewer average ones.
It is possible to talk about social mobility in general terms, but most researchers focus on one of five specific forms of mobility: educational mobility, occupational mobility, wage mobility, family income mobility, and wealth mobility. Each has its own interesting properties. We focus on two types: family income mobility and occupational mobility. The first—typically the domain of economists—is the extent to which an adult's (or family's) relative income or rank in the income distribution is similar to his or her father's (or father's family's) relative income or rank. The second— most often the province of sociologists— is the extent to which the status or type of job a person winds up with resembles that of his or her father or mother.
We review research on income and occupational mobility, examining changes in the opportunity structure and growth, as well as the effects of inequality. We first try to quantify the extent of intergenerational occupational and income mobility in the United States. We then compare estimates of mobility in the United States today with evidence both from the American past and from cross-national comparisons. Where possible, we discuss the intergenerational persistence of wealth and property as well. Intergenerational educational mobility is another fascinating topic, but it is beyond our scope in this review.