JUDY WOODRUFF: Today's plunge marked the fourth time in just over a week where the Dow Jones industrials have dropped by triple digits. Market volatility is at again near record levels.
We look at this and the larger picture with two people who have worked closely on economic policy. Christina Romer was the chair of the Council of Economic Advisers for President Obama until September 2010. She's a professor of economics at the University of California at Berkeley. And Matthew Slaughter served on President George W. Bush's Council of Economic Advisers from 2005 to 2007. He's now associate dean of the Tuck School of Business at Dartmouth College. And we thank you both for being with us.
Christina Romer, to you first.
The scary roller-coaster ride on the stock market continued again today. How do you explain it?
CHRISTINA ROMER, University of California at Berkley: Well, I think, obviously, one of the things about the stock market is it's very hard to explain the ups and downs...