Market Efficiency. In The Efficient Market Hypothesis on Trial professors Phillip Russell and Violet Torbey re-examine EMH and conclude that a refinement is in order. Their premise states:

The hitherto dominant paradigm in financial market research, the Efficient Market Hypothesis (EMH), has been put on trial recently and subjected to critical re-examination. The preliminary evidence indicates that the initial confidence in the Efficient Market Hypothesis might have been misplaced. It is observed that financial equilibrium models based on EMH fail to depict trading operations in the real world. Various anomalies and inconsistent results call for refinement of the existing paradigm. It is proposed in this article that a more coherent theory of stock market behavior can be developed by incorporating Keynesian ideologies on the speculative behavior of investors.

Warren Buffet is more concise: "I'd be a bum in the street with a tin cup if the markets were efficient."