[Book Review] Plight of the Fortune Tellers: Why We Need to Manage Financial Risk Differently

Risk management is about making decisions under uncertainty




☆☆☆☆☆
The main theme is that risk management is not about measuring risk, or assessing probabilities, but it is about making decisions under uncertainty. The author says that the existing framework of risk management, which is heavily based on “frequentist” approach to probabilities (i.e. repeatability under identical conditions, weak prior beliefs, etc.) does not necessarily serve for decision-usefulness associated with managing risks; “subjective” (Bayesian) probabilities tend to be better suited to the purposes. Focusing on the outcome of decisions relieves us from dogmatic probabilists and allows us eclectically to arrive at the best prediction we can, using whatever tool we have at our disposal. While the author’s argument appears to make a lot of sense, the Bayesian probabilities brings in subjectivity such as prior information/knowledge, which in itself seems helpful, I wonder what if we are not confident of such prior information, as we cannot know what we cannot anticipate (i.e. an “unknown unknown”: an uncertainty that is unanticipated)? Or put it differently, if we already have had good, reliable prior information about whatever the risk we attempt to assess, then, we would not have much to worry about to begin with, I presume….. Well, we probably should not try to rely on statistical approach to such an extremely high percentile to be considered effectively meaningless (I hasten to throw in my disclaimer here that I am not proficient enough in statistics to discuss the matter in detail!)
Those who have found Nassim Nicholas Taleb’s “The Black Swan” and “Fooled by Randomness” fascinating would be intrigued by this timely, engaging , and highly accessible account, which provides not only professional risk managers but also amateur investors like me with numerous insights.