Higher SES Friends Lead To Higher Incomes

 
From the New York Times.

Tyler Cohen at Marginal Revolution quotes from the source studies:

There are two new NBER papers written by large teams, headlined by Raj Chetty.  Here is an excerpt from the first paper:

The fraction of high-SES friends among low-SES individuals—which we term economic connectedness—is among the strongest predictors of upward income mobility identified to date, whereas other social capital measures are not strongly associated with economic mobility. If children with low-SES parents were to grow up in counties with economic connectedness comparable to that of the average child with high-SES parents, their incomes in adulthood would increase by 20% on average.

And this as a general introduction to the project:

….we measure and analyze three types of social capital by ZIP code in the United States: (i) connectedness between different types of people, such as those with low vs. high socioeconomic status (SES); (ii) social cohesion, such as the extent of cliques in friendship networks; and (iii) civic engagement, such as rates of volunteering. These measures vary substantially across areas, but are not highly correlated with each other.

The core data are taken from Facebook and anonymized.  And from the second paper:

We show that about half of the social disconnection across socioeconomic lines—measured as the difference in the share of high-socioeconomic status (SES) friends between low- and high-SES people—is explained by differences in exposure to high- SES people in groups such as schools and religious organizations. The other half is explained by friending bias—the tendency for low-SES people to befriend high-SES people at lower rates even conditional on exposure.

There is then this concrete result:

…friending bias is higher in larger and more diverse groups and lower in religious organizations than in schools and workplaces.

The cross-social class connectedness of people varies geographically (red places on the map below are more social class segregated and blue ones are less social class segregated in friendships):

Notably, there is great variation in cross-socioeconomic class connections within both "red states" and counties (politically) and "blue states" and counties (politically).

Within conservative leaning areas, the Great Plains and northern Mountain West are very connected across socioeconomic class lines, while the South and Southwest are very segregated.