So, what's a nudge? A nudge is some small feature of the environment that attracts our attention and alters our behavior.

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

Rip Van Winkle would be the ideal stock market investor: Rip could invest in the market before his nap and when he woke up 20 years later, he'd be happy. He would have been asleep through all the ups and downs in between. But few investors resemble Mr. Van Winkle. The more often an investor counts his money - or looks at the value of his mutual funds in the newspaper - the lower his risk tolerance.

The money has to be deferred with what they call "clawback," which means they can get it back if I lose it all. So that guy making ten million a year selling credit default swaps, if we're going to keep five million of it in escrow for ten years, and with the right to go back and get it, if he starts losing money, then we're going to give people the right incentives not too take so much risk.

A good rule of thumb is to assume that everything matters.

If people just put away what's left at the end of the month, that's a recipe for failure.

Why tie to gold? Why not 1982 Bordeaux?