And there are the so-called "black swans, " events of low probability and high impact.

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By defining human capital as an asset that must be grown and protected, investors can begin to ascertain how human capital issues impact overall portfolio risk and the probability of achieving their long-term financial goals.

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When it comes to high-impact low-probability (HILP) events, impact is so big, in both emotional and actual terms, that it swamps our understanding of the actual risk, which is often very small or unknowable.

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