Absolute income mobility obscures marginalized children's disadvantages.

Intergenerational mobility captures the distance between the socioeconomic positions of parents versus their adult children. Researchers measure this distance in absolute and relative units, such as absolute dollars and relative ranks. Absolute and relative mobility often diverge. For example, absolute mobility can rise while relative mobility declines. How should scholars and policymakers understand this divergence? We conclude that they should understand it as follows: absolute mobility is less reflective than relative mobility of marginalized children's socioeconomic disadvantages. We base this conclusion on analyses of survey, administrative, and simulated data on income mobility in the contemporary United States. We analyze multiple points of difference in mobility, which facilitates the recognition of several asymmetries. First, high-income children's experiences weigh more heavily in absolute-mobility trends than low-income children's experiences, particularly when economic growth is positive. Second, this asymmetry is more characteristic of absolute- than relative-mobility trends. Third, absolute-mobility differences across demographic groups are more prone than relative-mobility differences to obscure marginalized groups' socioeconomic disadvantages. These asymmetries have policy implications: We caution that focusing on absolute mobility as a policy target can divert attention away from society's most disadvantaged children.

Childhood Family Instability and Young-Adult Union Experiences: Black-White Differences in Outcomes and Effects.

Today's young adults have diverse union experiences; some enter enduring marital or cohabiting unions at young ages, but many delay or dissolve their unions or remain single. Childhood family instability-defined as parents' transitions into or out of romantic coresidential unions-offers one explanation for why some people are more likely than others to enter and exit unions. We evaluate whether this family instability hypothesis-a union-specific version of the general hypothesis that instability affects people across multiple life domains-can explain Black and White young adults' union formation and dissolution. Using data from the Panel Study of Income Dynamics' Transition into Adulthood Supplement (birth cohorts 1989-1999), we find that the marginal effects of childhood family instability on cohabitation and marriage are weaker for Black than for White youth. Further, Black-White differences in childhood family instability's prevalence are small. Consequently, novel decompositions that account for racial differences in instability's prevalence and marginal effects reveal that childhood family instability contributes little to Black-White inequality in young adults' union outcomes. Our results challenge the generalizability of the family instability hypothesis across racialized groups in the union domain. Explanations for Black-White differences in young-adult marriage and cohabitation reside beyond childhood family dynamics.

Is the Effect Larger in Group A or B? It Depends: Understanding Results From Nonlinear Probability Models.

Demographers and other social scientists often study effect heterogeneity (defined here as differences in outcome-predictor associations across groups defined by the values of a third variable) to understand how inequalities evolve between groups or how groups differentially benefit from treatments. Yet answering the question "Is the effect larger in group A or group B?" is surprisingly difficult. In fact, the answer sometimes reverses across scales. For example, researchers might conclude that the effect of education on mortality is larger among women than among men if they quantify education's effect on an odds-ratio scale, but their conclusion might flip (to indicate a larger effect among men) if they instead quantify education's effect on a percentage-point scale. We illuminate this flipped-signs phenomenon in the context of nonlinear probability models, which were used in about one third of articles published in Demography in 2018-2019. Although methodologists are aware that flipped signs can occur, applied researchers have not integrated this insight into their work. We provide formal inequalities that researchers can use to easily determine if flipped signs are a problem in their own applications. We also share practical tips to help researchers handle flipped signs and, thus, generate clear and substantively correct descriptions of effect heterogeneity. Our findings advance researchers' ability to accurately characterize population variation.

Marriage and Union Formation in the United States: Recent Trends Across Racial Groups and Economic Backgrounds.

Family formation in the United States has changed dramatically: marriage has become less common, nonmarital cohabitation has become more common, and racial and economic inequalities in these experiences have increased. We provide insights into recent U.S. trends by presenting cohort estimates for people born between 1970 and 1997, who began forming unions between 1985 and 2015. Using Panel Study of Income Dynamics data, we find that typical ages at marriage and union formation increased faster across these recent cohorts than across cohorts born between 1940 and 1969. As fewer people married at young ages, more cohabited, but the substitution was incomplete. We project steep declines in the probability of ever marrying, declines that are larger among Black people than White people. We provide novel information on the intergenerational nature of family inequalities by measuring parental income, wealth, education, and occupational prestige. Marriage declines are particularly steep among people from low-income backgrounds. Black people are overrepresented in this low-income group because of discrimination and opportunity denial. However, marriage declines are larger among Black people than White people across parental incomes. Further, most racial differences in marriage occur among people from similar socioeconomic backgrounds. Family inequalities increasingly reflect both economic inequalities and broader racial inequalities generated by racist structures; in turn, family inequalities may prolong these other inequalities across generations.

Tenancy, Marriage, and the Boll Weevil Infestation, 1892-1930.

In the early twentieth century, the cotton-growing regions of the U.S. South were dominated by families of tenant farmers. Tenant farming created opportunities and incentives for prospective tenants to marry at young ages. These opportunities and incentives especially affected African Americans, who had few alternatives to working as tenants. Using complete-count Census of Population data from 1900-1930 and Census of Agriculture data from 1889-1929, we find that increases in tenancy over time increased the prevalence of marriage among young African Americans. We then study how marriage was affected by one of the most notorious disruptions to southern agriculture at the turn of the century: the boll weevil infestation of 1892-1922. Using historical Department of Agriculture maps, we show that the boll weevil's arrival reduced the share of farms worked by tenants as well as the share of African Americans who married at young ages. When the boll weevil infestation altered African Americans' opportunities and incentives to marry, the share of African Americans who married young fell accordingly. Our results provide new evidence about the effect of economic and political institutions on demographic transformations.

Childhood Family Structure and Intergenerational Income Mobility in the United States.

The declining prevalence of two-parent families helped increase income inequality over recent decades. Does family structure also condition how economic (dis)advantages pass from parents to children? If so, shifts in the organization of family life may contribute to enduring inequality between groups defined by childhood family structure. Using National Longitudinal Survey of Youth data, I combine parametric and nonparametric methods to reveal how family structure moderates intergenerational income mobility in the United States. I find that individuals raised outside stable two-parent homes are much more mobile than individuals from stable two-parent families. Mobility increases with the number of family transitions but does not vary with children's time spent coresiding with both parents or stepparents conditional on a transition. However, this mobility indicates insecurity, not opportunity. Difficulties maintaining middle-class incomes create downward mobility among people raised outside stable two-parent homes. Regardless of parental income, these people are relatively likely to become low-income adults, reflecting a new form of perverse equality. People raised outside stable two-parent families are also less likely to become high-income adults than people from stable two-parent homes. Mobility differences account for about one-quarter of family-structure inequalities in income at the bottom of the income distribution and more than one-third of these inequalities at the top.

Trends in Income Insecurity Among U.S. Children, 1984-2010.

Has income insecurity increased among U.S. children with the emergence of an employment-based safety net and the polarization of labor markets and family structure? We study the trend in insecurity from 1984-2010 by analyzing fluctuations in children's monthly family incomes in the Survey of Income and Program Participation. Going beyond earlier research on income volatility, we examine income insecurity more directly by analyzing income gains and losses separately and by relating them to changes in family composition and employment. The analysis provides new evidence of increased income insecurity by showing that large income losses increased more than large income gains for low-income children. Nearly one-half the increase in extreme income losses is related to trends in single parenthood and parental employment. Large income losses proliferated with the increased incidence of very low incomes (less than $150 per month). Extreme income losses and very low monthly incomes became more common particularly for U.S. children of nonworking single parents from the mid-1990s.

Income Inequality and Intergenerational Income Mobility in the United States.

Is there a relationship between family income inequality and income mobility across generations in the United States? As family income inequality rose in the United States, parental resources available for improving children's health, education, and care diverged. The amount and rate of divergence also varied across US states. Researchers and policy analysts have expressed concern that relatively high inequality might be accompanied by relatively low mobility, tightening the connection between individuals' incomes during childhood and adulthood. Using data from the Panel Study of Income Dynamics, the National Longitudinal Survey of Youth, and various government sources, this paper exploits state and cohort variation to estimate the relationship between inequality and mobility. Results provide very little support for the hypothesis that inequality shapes mobility in the United States. The inequality children experienced during youth had no robust association with their economic mobility as adults. Formal analysis reveals that offsetting effects could underlie this result. In theory, mobility-enhancing forces may counterbalance mobility-reducing effects. In practice, the results suggest that in the US context, the intergenerational transmission of income may not be very responsive to changes in inequality.

Tenancy and African American Marriage in the Postbellum South.

The pervasiveness of tenancy in the postbellum South had countervailing effects on marriage between African Americans. Tenancy placed severe constraints on African American women's ability to find independent agricultural work. Freedwomen confronted not only planters' reluctance to contract directly with women but also whites' refusal to sell land to African Americans. Marriage consequently became one of African American women's few viable routes into the agricultural labor market. We find that the more counties relied on tenant farming, the more common was marriage among their youngest and oldest African American residents. However, many freedwomen resented their subordinate status within tenant marriages. Thus, we find that tenancy contributed to union dissolution as well as union formation among freedpeople. Microdata tracing individuals' marital transitions are consistent with these county-level results.

Racial Inequality Trends and the Intergenerational Persistence of Income and Family Structure.

Racial disparity in family incomes remained remarkably stable over the past 40 years in the United States despite major legal and social reforms. Previous scholarship presents two primary explanations for persistent inequality through a period of progressive change. One highlights continuity: because socioeconomic status is transmitted from parents to children, disparities created through histories of discrimination and opportunity denial may dissipate slowly. The second highlights change: because family income results from joining individual earnings in family units, changing family compositions can offset individuals' changing economic chances. I examine whether black-white family income inequality trends are better characterized by the persistence of existing disadvantage (continuity) or shifting forms of disadvantage (change). I combine cross-sectional and panel analysis using Current Population Survey, Panel Study of Income Dynamics, Census, and National Vital Statistics data. Results suggest that African Americans experience relatively extreme intergenerational continuity (low upward mobility) and discontinuity (high downward mobility); both helped maintain racial inequality. Yet, intergenerational discontinuities allow new forms of disadvantage to emerge. On net, racial inequality trends are better characterized by changing forms of disadvantage than by continuity. Economic trends were equalizing but demographic trends were disequalizing; as family structures shifted, family incomes did not fully reflect labor-market gains.