More than half of the companies that comprise the Standard & Poor's 500 Index have reported earnings for the quarter, and two-thirds of them have exceeded expected earnings per share by an average of 7%, according to Thomson Financial, compared with 4.2% over the past eight quarters. Two explanations spring to mind: Either companies aren't very good at forecasting, which means they shouldn't give profit targets at all, or they are purposely low-balling to spur post-earnings enthusiasm in the stock market.