Answer:
In every form of analysis, it is always safer to take a macro or holistic view of the situation. This is true for the investment performance of a manager. One investment decision that went right does not suffice to classify an investment portfolio manager as proficient, neither is one that went south enough to tag him deficient.
The forecasting ability of managers, on the balance of probability, will vary for different cases, with a helicopter view of providing a more accurate measure of their performance.
However, if it was possible to analyse the market for volatility and adjust our forecasts it becomes unnecessary to look at and analyse all the information from a 12-month cycle before coming to terms about the performance of the manager.
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