The United States’ highly expensive higher education system means that many students leave college with debt, and that many students have trouble paying back that debt.

These two problems, however, affect two very different sets of student groups. A set of interactive maps published Tuesday by the Washington Center for Equitable Growth illustrates how student debt and student loan delinquency are inversely related.

The first map shows the average balance of student loans in the Boston area (the darker areas indicate higher rates of debt). The second map shows the student loan delinquency rate.

Average loan balance in the Greater Boston area. —Screenshot via Washington Center for Equitable Growth

Loan delinquency rate in the Greater Boston area. —Screenshot via Washington Center for Equitable Growth

What’s clear is that the areas with the most student debt are not the areas where student are falling behind on paying off their loans. Rather, loan delinquency seems to be associated with the areas with the lowest median income, according to the authors.


Kavya Vaghul, a research analyst and one of the authors of the Mapping Student Debt project, told Boston.com they noticed the relationship in most major metropolitan areas across the country.

“What’s striking in the Boston area is the Dorchester neighborhood,’’ Vaghul said. “We see that low-income zip codes in this neighborhood have high delinquency rates. When contrasting this to the rest of Boston, a relatively high-income area, you’ll see that average loan balances are high in the northern and western parts of the city, probably as a result of its higher-education institutions.’’

For example, in the 02121 zip code, which includes parts of Dorchester and Roxbury, the median income is $28,238, one of the lowest in the Boston metropolitan area. And while students in that area have an average amount of debt, the neighborhood has a much higher rate of loan deliquency than anywhere else in Boston.

On the other hand, parts of Cambridge, Brookline, and Back Bay, where median incomes range from $70,000 to $100,000, the student loan balance is described as “astronomical’’ — over 100 percent more than the national average. Yet, loan deliquency in that area is extremely low.

Vox’s Libby Nelson wrote Tuesday how the pattern complicates the college affordability crisis.


“This contradiction, that the people who borrow the most in student loans often end up doing fine, makes it hard to create a sensible student loan policy,’’ she wrote. “Many people think of the student loan problem as all about balances. But it’s really about the hidden, struggling borrowers, whose inability to pay back their loans can follow them for life.’’

The rough association between student debt, income, and (inversely) loan deliquency can be seem across Massachusetts.

Average loan balance in Massachusetts. —Screenshot via Washington Center for Equitable Growth

Medican income in Massachusetts. —Screenshot via Washington Center for Equitable Growth

Loan delinquency in Massachusetts. —Screenshot via Washington Center for Equitable Growth

Vaghul and co-author Marshall Steinbaum point to two “mutually consistent’’ theories that explain this relationship. The first is that even though graduate students take out the largest student loans, additional education tends to return higher-salary jobs that enable them to pay off that debt. According to the Department of Education, 7 percent of graduate students defaulted on their student loans.

Another possible factor is the rise of for-profit colleges, according to Vaghul and Steinbaum.

“Because these borrowers face poor labor market outcomes and lower earnings upon graduation (if they do in fact graduate), their delinquency rates are much higher,’’ they wrote. “This is further complicated by the fact that these for-profit college attendees generally come from lower-income families who may not be able to help with loan repayments.’’

Vaghul and Steinbaum also suggest that access to credit, which has for decades disproportionately disadvantaged poor and minority populations, contribute to the income-delinquency relationship.

Click over to the Washington Center for Equitable Growth’s full interactive map to see what the geography of student debt looks like across the country.