Is there a market for somebody selling a credit card that helps people pay down their balances? I think the question is yes. But it would have to be sold by a bank that's really willing to invest in being a trusted partner with its consumers, because they will make less money on each consumer.

My mantra is if you want to help people accomplish some goal, make it easy.

Why tie to gold? Why not 1982 Bordeaux?

Most economists, including me, agree that longevity insurance would make sense for a lot of people.

The assumption that everybody will figure out how much they have to save and then will just implement that plan is obviously preposterous.

"Save more tomorrow" is a nudge to help people do what they know they want to do, which is save more, but they can't bring themselves to save more now. Just like many of us are planning to go on diets next month, or maybe in two months, certainly not tonight.

Retirement savings is probably behavioral economists' greatest success story. It is a prototypical behavioral-economics problem because saving for retirement is cognitively hard - figuring out how much to save - and requires self-control.