Summer memories and a major study on friendship and mobility

by Jean Rhodes

When I was growing up Allendale, NJ in the 1960’s and 70’s, a family’s social class didn’t define life and determine social mobility the way it does now. Resources varied pretty widely across neighborhoods and families, but Allendale’s 6,000 residents all seemed to know each other. We all spent our long, unscheduled August days at the same town pool, attended the same schools, biked on the same streets, and were coached by each other’s parents. Parents attended the rare back-to-school night but, for the most part, our worlds were separate. 

 Like so many other small towns across America, Allendale has changed dramatically in the ensuing 40 years.  Starting in the late 1970s, income inequality and wealth disparities began to grow and have now reached levels not seen since the 1920s. As the federal government cut tax rates for the wealthy and workers’ bargaining power declined, income inequality soared and public support for welfare programs decreased. To a growing extent the prosperous, educated business and professional classes are now living apart in growing class- and race based segregation from the rest of the country, and Allendale is no exception. It is now a much tonier, more racially and socially homogeneous community. My high school’s hallways are now filled with educated parents who, when not volunteering in the classrooms, are running school benefits.  Many families who once lived in our mixed income town now occupy a different, more isolated existence. For the two thirds of the U.S. adult population without a college degree, incomes are no longer growing, and rates of drug use, divorce and single parenthood are significantly higher in their communities. Rates of incarceration, which are five times what they were back in the mid-1970’s, disproportionately affect poor, rural, and non-white communities, consigning seven percent of American children to having a parent behind bars at some point in their childhood (Turney & Godsell, 2018). With fewer hours to spend cultivating their children’s interest, less extensive social networks, and the growing threats addiction, gun violence, and criminal justice involvement, parents put relatively more emphasis on discipline and safety over creativity and enrichment. Our analyses of the Add Health data set show that young people on the lowest rungs of the socioeconomic status feel less emotionally connected to and supported by their parents and that when such youth find mentors, they are less likely to rely on them for emotional support.  What’s more, the mentors of lower income youth tend to be the “strong ties,” who are  not as well positioned to help connect them to opportunities. It has become increasingly clear that relationships that cross class and cultural boundaries are vitally important. 

In Brooking Institution researchers Richard Reeves and Coura Fall, excellent summary of Raj Chetty and colleagues[1] recent study, these relationships are vitally important. As they note (the remainder of this piece is excerpted from their summary):

“The latest Opportunity Insights report from Raj Chetty and colleagues[1] suggests that one ingredient that may trump all the others: Friends.


Drawing on a massive dataset, comprising the social networks of 72.2 million users of Facebook aged between 25 and 44 years, Chetty and his team are able to assess how far social networks influence economic mobility. The richness of their data permits analysis at a very granular level, down not only to zip codes, but individual colleges and high schools. Their two papers Social Capital I: measurement and associations with economic mobility and Social Capital II: determinants of economic connectedness have just been published in Nature along with supplementary data here and here. As usual they have also created an interactive and public use version of the data.

The findings are striking and certain to have a profound impact on discussions of economic mobility. The headline finding is that at the community level, cross-class connections boost social mobility more than anything else, including racial segregation, economic inequality, educational outcomes, and family structure.

Creating more connections across class lines – either through greater economic integration of our institutions and neighborhoods or more opportunities for cross-class social engagement – looks to be the most promising route to improving rates of upward economic mobility in the U.S.

Here we summarize seven key findings from the research, as well as some implications for policy.

1. Friendship networks are strongly class based, especially at the top

People are most likely to be friends with people of a similar socioeconomic status (SES), especially at the top of the ladder. … one in three of the friends of those in the top SES decile are from the same decile, compared to just 24% from the whole bottom half of the income distribution:

2.  Rich people make friends of college classmates, poorer people make friends of neighbors

There are also marked class differences in how and where people make friends. For high-SES people, college plays a much bigger role in the creation of friendship networks – mostly for the obvious reason that they are more likely to have gone to college in the first place: For those from working class or middle-class backgrounds, neighborhood networks are much more important, followed by religious communities. As the team writes:

“Individuals with the lowest SES make about four times greater a share of their friends in their neighborhoods (residential ZIP codes) compared with individuals with the highest SES…Neighborhoods therefore play a larger role in defining the social communities of low-SES individuals, perhaps explaining why where one lives matters more for the economic and health outcomes of lower-income individuals than higher-income individuals.”

3.  The Midwest really is friendlier than the northeast…

There are two factors that can influence the formation of friendships across class lines:

  • lack of exposure to people of a different background (and particularly of lower-SES people to higher-SES people)
  • “friending bias,” which means that even when there are people of different backgrounds around, friendships remain strongly class-based

4.  Economic connectedness is the only form of social capital that boosts mobility

Chetty and his colleagues examine three types of social capital:

  • economic connectedness (EC), based on the extent of friendships across class lines
  • social cohesion, based on measures of the thickness of social ties within communities
  • civic engagement, for example as expressed by rates of volunteering

Strikingly, they find that only the first form of social capital – economic connectedness – is associated with higher rates of economic mobility:.

5.  In fact, economic connectedness boosts mobility more than anything else

Drawing on earlier work, the Chetty team can compare the importance of social capital, in the form of economic connectedness, for economic mobility compared to other factors. The results here are perhaps the most remarkable of all. Drawing on a careful analysis teasing out the relevance of various factors, they find that economic connectedness is a stronger predictor of upward mobility than any other:

6.  For upward mobility, it’s better to live in a more connected place than a richer place

What this means is that mobility rates are more influenced by the degree of economic connectedness in a neighborhood than by other factors, such as inequality, segregation or income. Zip codes with higher levels of economic connectedness have better rates of upward mobility, even if they are lower income:

7.  Friending bias and economic segregation contribute equally to lack of connectedness

Which of the two barriers to economic connectedness – lack of exposure, or friending bias – matters the most? The conclusion:

“Both exposure and friending bias remain strongly predictive of counties’ causal effects on upward mobility, implying that moving to a place with greater exposure or lower friending bias at an earlier age increases the earnings in adulthood of children who grow up in low-income families.”

So what?

Scholars like Robert Putnam and our own colleague Camille Busette, Director of the Brookings Race, Prosperity, and Inclusion Initiative have argued for the importance of social capital – especially of the “bridging” kind expressed by economic connectedness – for economic opportunity. But this new research provides a wholly new empirical basis for this connection. This work suggests that the importance of relationships goes beyond obvious advantages such as job referrals: after all, the studies show that moving to a highly connected place even early in childhood makes a difference to long-term upward mobility….Chetty and his colleagues remind us that while interventions to support individuals, for example through educational investments or job programs are important, the web of relationships that people build along the way can be equally impactful. It is surely true that people can get by with a little help from their friends. But it also looks like their friends can help them to get ahead.”