From Richard Russell in Dow Theory Letters:

...Was March 9 the ultimate bear market low?

The essence of Dow Theory has to do with VALUES. At the March low the price/earnings ratio for the Dow was 25.79 and the dividend yield for the Dow was 3.99%. For the S&P 500 the P/E was 28.38 while the dividend yield was 2.98%. Consider the following -- this bear market has, so far, qualified as a MAJOR bear market. Stock values, across the board, are down 50%. Most major bear markets in history have taken stocks down to the point where price/earnings for both the Dow and the S&P are below 7, while at the same time dividend yields are at 6% or higher.

I would expect this bear market, regardless of intervening rallies, to end with stocks selling at "great values," meaning P/E ratios well below 10 and dividend yields in the 5-6% area. We've seen nothing like that so far. All of which makes me believe that we are now simply in a bear market correction

Learn more about the excellent Dow Theory Letters...

This Richard Russell quote is a must read

Richard Russell: Bernanke wants mortgage rates at 3-4%; "massive assault"