Investing without true information is just speculation. How do we know we have true information that can predict security returns? On one level, predicting a market crash is not enough, even if you are correct once. In the same vein, neither is finding the correct target prices for a couple of stocks a proof of skill. The key to investment success is consistency in forecasting (skill) applied repeatedly (breadth). We have Grinold and Kahn (2000) to thank
Great distinction - being right once does not mean you have a repeatable investment system. And a few forecasts does not mean you have a robust framework for security analysis.
However, a quantifiable forecasting edge across a wide array of assets suggests skill.
