Here are a couple of pieces from two respected publications on the folly of trying to make predictions about investments:
From the New York Times:
Tactical asset managers offer some secret algorithm that can analyze macroeconomic forecasts and valuation formulas in hopes of identifying the ideal time to get in and out of broad asset classes like stocks and bonds. The problem is, none of us knows exactly when these turning points will happen.
After tracking 68 experts and 6,582 market forecasts, CXO Advisory Group has concluded that the average market prediction offered by experts has been below 50% accuracy.