With the vaunted price/earnings ratio losing its mojo as a market gauge, investors are seizing on better ways to value stocks—some of them far removed from corporate earnings statements.

What is wrong with the P/E? In short, the "e" can't be trusted. The Standard & Poor's 500-stock index's average P/E has dropped to 12.3 times earnings based on analyst forecasts for the next four quarters, below the 52-week average of around 14.3.

But...