A good article and a valid point. I have done that exercise before, and my conclusion was that that wasn't enough information. It isn't the news that matters, its the interpretation of the news that skews markets. What you need is some sort of gauge of media interpretation of market sentiment. A 'positivity index' if such a thing can be constructed. Boils down to the old story of Charles Dow believing the time to get out of a stock was when his shoeshine boy was giving him stock tips.