1. The historical performance created by fund managers is influenced by their investment level (alpha) and luck (volatility). In order to objectively judge a fund manager's investment skills, we need to use scientific methods to separate skills from luck, so as to select those fund managers who are really skilled.

2. If we want to scientifically judge the real investment skills of fund managers, the historical performance in the past three years is far from enough. It is undoubtedly a "blind choice" for investors to choose funds only based on these historical records.

3. Sometimes investors may not be able to make money from fund managers who have proved their ability to create "alpha" through statistical calculation. It depends largely on the timing of investors' buying.

4. If you don't have enough financial knowledge, resources and information to scientifically and rigorously analyze the investment ability of fund managers, then a better choice is to give up choosing active funds and buy and hold low-cost index funds (ETFs) for a long time.