Being wealthy doesn't mean having all the money in the world, just not having to worry about it.

Lesson 11 – Your Life Is Only One Experiment

To be fair, I must note that a few theorists have offered a plausible case against reversion based on chaos theory, arguing that “off-the-chart” results occur in real life that normal statistics claim are impossible. (For instance, based on the calculated daily volatility of stocks, there is simply no way the U.S. stock market could Read more »

Lesson 10 – The Market Is Not a Pure Coin Flip

In the previous lesson, I promised to provide three reasons to use the median (which improves with diversification) instead of the mean (which does not). I’ll start with my weakest argument, although it is one shared by many academics in the field of finance: Equity returns revert toward long-run averages. The book that first popularized Read more »

Lesson 8 – Modern Porfolio Theory

Please read this one slowly (and, hopefully, more than once). Modern Portfolio Theory (MPT) is one of the most important concepts in investing to understand. It isn’t obvious: indeed, Harry Markowitz won a Nobel Prize in economics for coming up with this idea in 1951. (So the idea isn’t really all that modern at this Read more »

Lesson 7 – The Problem of the Short Term

People sometimes get the impression that I think all investors, regardless of their personal circumstances, ought to keep 100% of their investment funds in stocks all of the time. Now I won’t be so disingenuous as to say, “Nothing could be further from the truth.” But I will say that isn’t the truth. As books such Read more »

Lesson 6 – The Real Meaning of Safety

There are some people who believe that a retiree’s portfolio should consist primarily of “safe” investments. In this context, safe generally means low volatility. If, for example, you keep all your money in a federally insured bank account, then it will never have a day when it goes down in value. There are, however, two Read more »

Lesson 3 – How Much Do You Spend?

Determining your spending needs is darn near impossible because all of us “need” very little to survive. For millennia, the average person in the world lived on the equivalent of one dollar a day. Only during the industrial revolution did standards of living start rising significantly above that, and only in some countries. Even today, Read more »