probabilities

The High Tech Rear View Mirror

© Can Stock Photo / canbedone

Once upon a time, we wrote that pretending present and future risk can best be measured by past volatility is akin to driving down the highway with eyes firmly planted on the rear view mirror. (Our theory is the future will not be like the past, so the windshield is a better thing on which to focus.)

The current market upset is the first one featuring the latest generation of so-called risk analytics. These high tech tools generate risk numbers for individual investments as well as entire portfolios. They are entirely based on past volatility. Incorporating frequent updates to the database of past price behavior and enabling near-instantaneous assessments expressed as an index number (say, 1 to 100), they seem quite scientific and highly analytical.

But all of this precision is predicated on the idea that past volatility is a measure of present and future investment risk. So in the latest version, it is like driving down the highway with eyes firmly fixed on an array of rear view mirrors, wide-angle and telephoto and high-definition.

The interesting thing is, when the inevitable downturn occurs, the ‘volatility equals risk’ crowd is quick to point out that their statistical methods are designed to predict what will happen, with a 95% probability. So if you run into a wall while focused on the rear view mirror, there was nothing wrong with the analytics – you just landed in the 5%.

Call us what you want, but a system designed to ferret out risk that fails exactly when you do need it to work may not be all that useful. (An elevator that does not crash to the basement 95% of the time would not be useful, either, in our opinion.)

We will continue to work with our understanding that volatility is a feature of long term investments. It necessitates a long time horizon, so the effect of temporary declines may be mitigated by time. Short term money needs to be kept out of long term investments. And we will keep our eyes focused on the future, not the past.

Clients, if you would like to talk about this or anything else, please email us or call.

And Now, the Weather

© Can Stock Photo / ifeelstock

When you watch the news and the weather forecaster tells you there is an 80% chance of rain tomorrow, what exactly does that mean?

It might rain tomorrow, or it might not. It says rain is more likely than not. So if there is no rain after all, does that mean that the forecast was wrong?

Forecasting is often a fuzzy subject. No one can see the future with 100% certainty, so predictions are often spoken of in terms of probabilities. But we as humans are generally not good at thinking in terms of probability. An 80% chance is far from a sure thing, but when someone tells us something is 80% likely to happen, it can sometimes feel like one.

This is particularly true when it comes to trying to predict one-time events. If you flip a coin and it comes up tails, you can keep flipping it and see that it will still come up heads about half the time. If the weather forecast says there is an 80% chance of rain next Tuesday, there is only one next Tuesday. If Tuesday comes and goes without any rain, it sure feels like the forecaster blew it.

Economic and financial forecasting runs into the same problem. First, a forecast is only as good as its model. Economic projections may include assumptions that prove to be unfounded. But even a good forecast is limited to predicting a range of probabilities. If an analyst tells you they think there is an 80% chance that the market will go up this quarter, all they are really saying is that it might go up and it might go down. You probably did not need an analyst with a fancy model to tell you that.

We put little faith in short term market predictions. Even if they are accurate, you can probably not afford to bet the farm on them. We prefer to take a longer-term view. We cannot be sure how an investment will perform over the next month or next year, and do not believe in speculating on short term results. We feel much more comfortable in the trend over the long run.

Clients, if you have any thoughts or questions, please call or email us.


The opinions voiced in this material are for general information only and are not intended to provide specific advice or recommendations for any individual.

All investing involves risk including loss of principal. No strategy assures success or protects against loss.