In this paper written by Brad Steiman of DFA, he proposes the happiness equation being that if your life as experienced gives you more than what your perceptions of what life should be - then you will be happy or at least avoid being unhappy. Hmmm - so all I have to do is lower my expectations? Ha ha.So how is this tied to investing you ask? Evidence Based Investing takes advantage of several long term market behaviors - premiums over and above what the overall market has to offer. In other words with Evidence Based Investing, the investor experiences a higher return than what is expected from the overall market return. Sounds a lot like the happiness equation. And thus you have the premise of the paper.We've referred to the premiums many times. If you recall these "premiums" exist all over the world. We break the world into four parts, investing in three of the four. The USA, other developed countries and emerging market countries. The fourth type of country is "frontier" countries. Frontier countries have systemic issues making them too risky.The global premiums are: small company stock outperforms large company stock, value stocks outperform growth stocks and higher profitability company stock outperforms lower profitability. It takes skill to implement these concepts and in our judgment, DFA is the world's leader. The implementation is to overweight or "tilt" in the areas of outperformance. For example if small stocks are 15% of the market value, perhaps you own them at 25%. You still own the "entire market" and therefore keep diversification.The paper goes into the premiums in detail including pointing out how they ebb and flow year to year, 5 years to 10 years. They are NOT always present - sometimes they perform lower than the overall market. But they are persistent - they RETURN. Sometimes they not only return, they SOAR above their long term average.