Rosen: What year was this?

Edin: This was in 2010. And I was thinking, this is really different. What does it mean to live with no cash? Right? Even if you're getting a lot of income benefits.

Luke came to visit Harvard in the fall, where I was teaching, and I immediately remembered that he was the guy with the expertise on the very dataset that could answer the question of whether what I was seeing was widespread or just sort of an anomaly of the households I had happened to run into in Baltimore.

Sure enough, he had just the right algorithm already on his computer for another analysis. And within a few days, you know, not only did we learn that it was big— and I'll let Luke fill in his part of the story—that half the people who fit in the category didn't even get food stamps and only a very small portion had housing subsidies. It was actually far deeper than even we realized.

H. Luke Shaefer: We started with this definition of just asking, “What kind of cash income is coming in from the house?” This could be from earnings, or any gifts from family and friends, public programs that come in dollars, odd jobs, etc. We wanted to be as comprehensive as possible. Our baseline number [of families with cash incomes of less than $2.00 per person per day] goes from, in 1996 (about the time we're making a big change to our social safety net) about 636,000 families who fit that profile, and by 2011, it’s more than doubled to about 1.5 million families with three million children who are reporting cash incomes of less than $2.00 per person per day. Even when you account for some of these major programs like SNAP (Supplemental Nutrition Assistance Program)—which is what we call food stamps now—the Earned Income Tax Credit, public housing, you still get an increase of about something around 50 percent between 1996 and 2011 in the number of families below the threshold.

As we got into the work, what we really saw was that in a modern society you need some cash to get out of those circumstances; you need some cash to basically keep your family going day-to-day.

Edin: In the third world, often, the economies are barter economies, so cash is only one means of exchange. Whereas in the United States, it's very nearly the only way.

Rosen: What are some of the strategies you saw people deploying in order to get by without cash?

Shaefer: There's sort of a constant, perpetual state of crisis. And then, what we really see, is that people spend a significant amount of their time trying to—it's really work—trying to generate that small amount of cash.

[One woman we talked to] in Johnson City, Tennessee, donates plasma two times a week—as often as the law will allow, if her body can take it. That’s a pretty arduous process. She gets paid $30 for it every time she goes. You can see in a lot of the families that we got to know these little divots in the creases of their elbows, where they've given plasma so many times, there’s a little scar.