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

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.

I think the people who've been the most overconfident in our business in the last decade have been the people that called themselves risk managers.

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

Why tie to gold? Why not 1982 Bordeaux?

When should we nudge and when should we shove, I think, it's a political judgment. Obviously in some situations we need shoves, we need laws. Fraud is against the law, murder is against the law, drunk-driving is against the law. We don't need just nudges.

There are cases when I can make myself better off by restricting my future choices and commit myself to a specific course of action.