It’s time that Americans learn how to save. Last year, we saved an average of 4.5 percent of household income — about half the historic rate — and most of that was concentrated among wealthier households. So it’s understandable that a number of groups are fixated on teaching the poor to save money. But a growing number of them are recognizing that to enter the economic mainstream, people also need good credit. (Even the post office has explored the possibility of modest banking and loan services for customers.) This can be a hard sell. “We’re fighting against the sentiment that you should cut up all your credit cards,” says Ricki Granetz Lowitz, a director at the Local Initiatives Support Corporation.

Yet saving and responsible borrowing, Lowitz realized, amount to the same thing: putting aside small sums to reach a goal. So she took the type of matched savings account that is used to encourage low-income people to save and tweaked it into something called Twin Accounts — the sort of loan that Shavers received — which builds both savings and credit. “I thought that people who were poor paid more for everything, and that’s absolutely not true,” she says. “It’s people with poor credit.” Eugene Reese, a 38-year-old candy-factory worker who just paid off his Twin Accounts loan, remembers trying to buy a $6,500 Cadillac. Another customer had $500 and a credit score above 700. Reese had $2,800, but no credit. The other guy got the car. “It made me realize that saved money — you might as well just keep it under your pillow,” Reese says, “because it doesn’t really matter anymore.”

From a behavioral-economics perspective, borrowing can actually be easier than saving, and not just because it offers instant gratification. While a vow to save $100 a month may quickly go the way of many diets, owing someone else $100 a month is a powerful motivator. Jonathan Morduch, an economist at New York University who studies the spending habits of low-income families, tells the story of Khadeja, a woman from Bangladesh who borrowed money at 36 percent interest to invest in gold jewelry. She knew she would most likely never be able to save enough to get it, but she would be sure to make her payments to the lender. “Khadeja saw the truth of an odd-sounding paradox,” Morduch and his co-authors wrote in “Portfolios of the Poor: How the World’s Poor Live on $2 a Day.” “If you’re poor, borrowing can be the quickest way to save.”

Khadeja may have paid more to borrow, but she was also buying a service — being forced to pay. Most of us already make constant use of this service, managing our money by borrowing and saving at the same time. In 2000, two business-school professors found that 90 percent of Americans with credit-card debt also had liquid assets, and about a third of them had enough to pay off the entire debt. But they didn’t. One reason is that if you spend your savings, you’re back to zero quickly. So you may prefer to pay a little more to borrow while keeping something in reserve. “We use credit cards all the time, so why shouldn’t other people be able to borrow as needed?” Morduch says. “They have the same needs. The impulse to stay away from helping people get access to credit is based on good intentions, but it’s not based on an understanding of how people live their lives responsibly.”