"When will the stock market drop?" or, "How much does a market drop hurt me?" The historic close of the Dow Jones Industrial Index above 23,000 this week, one day before the historic 30-year anniversary of the largest one-day drop of 23% of the Dow Jones Average has...

One of the most overlooked and yet most important aspects of long term investing is efficiency. The concept of efficiency touches our everyday lives in so many routine ways we take it for granted. We set the thermometers down or up when we are away to conserve money and energy use. We recycle to reduce the waste going to landfills and slow the drain on our natural resources. We are more gentle on the accelerator when gasoline prices are high. We might even think to remove unnecessary weight of stuff on the seats and in the trunk that serve no purpose in our daily commute.

In the investment process there are things which can be controlled; such as expenses, taxes, and under-performing market indices, and there are things that cannot; the uncertainty of markets. It is, however, quite possible to measure uncertainty not only of historical market returns, but also of potential market returns. So why is it important for investors to measure uncertainty and how is it measured?