Regression to the Mean – it’s everywhere

There is a statistical concept I learned about from Dr. Dave Shafer: Regression to the Mean. It’s a simple concept, but one that when ignored, can cause enormous financial headaches. In essence, things can and do revert back to the mean rates.  The more extreme things get from the mean, the sharper things will swing back to the mean. Hence it is important to learn what the mean rate is, and not build on top of extreme positions.

A financial example

The Dalbar Report has been published for 20 years+. Each year, they do a lookback to see how investors that buy mutual funds fare. And the results are the same: terribly! The average rate is in the neighborhood of 4%. The market itself may grow by a bigger amount. But we aren’t the market, we are individual investors. To shoot for 12% as certain radio personalities advocate would entail getting triple the average rate of everyone around you. If you visit a financial planner and he pitches some precious metals mutual fund that grew by 85% over the past two years, you are setting yourself up for a shocking correction. For something that extreme, a huge correction is coming. See why people say “don’t chase returns?”

A gambling example

This concept appears in other places. A classic one are casinos. I’ve had friends point out that roulette wheels have no memory. The table doesn’t remember the previous spin, so the odds are the same. That isn’t what “memory less” means in betting odds. A betting system with memory is where a form of “state” exists. Such as dealing cards. Each card you receive is impacted by what was dealt previously. Betting red vs. black pays 50/50 odds. If you see red come up ten times in a row, odds are starting to mount that black will be next. The reason casinos stay in business, i.e. make money, is because they count on regression to the mean. They know that red and black will shift back and forth based on these odds. And the casino house DOESN’T PAY the odds. For red and black, they put two extra numbers on the wheel that are neither, but still pay you as if those losing options don’t exist. This is their cut, and is something like 3.5% on the average (if memory serves). Every game they play is based on regression to the mean and they aren’t stupid.

A literary example

As my final example, look at any industry. There are always big, visible leaders. For authors of fiction, there are best selling authors like J.K. Rowling, Michael Crichton, and others. They make big money. This draws other people into the field. In truth, a lot of people never get published. A vast number of people that do, never make big money. Regression to the mean says that if you average all these people together, the industry as a whole doesn’t average big pay for most people. If and when that average starts to climb, basic economics says that more people will flock to it, and pull the average back down. When the average falls, people will leave it, allowing the average to rise.

Take this concept and look around. You may start to notice it elsewhere. So what does it mean? When building a wealth building plan, use the averages to your advantage.

  • Most people don’t save a lot of money. First step: save money!
  • A lot of people count on other people to earn big money for them. Second step: get active and learn how to do it yourself!
  • Too many people get caught up in paying fees instead of picking avenues that actually build wealth. Third step: Shop around for vehicles that have a long history of building wealth and THEN be willing to pay the best experts to do it right.

Happy wealth building!

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