Anyone who really wants to understand the arguments about quarterly reports etc should check out Naseem Talebs remarkable book “Fooled By Randomness”.
In the book he argues that time scale is important in judging performance, and he uses a simple Monte Carlo simulation to illustrate this. The following passage is taken pretty much word for word from the book.
"Lets take the example of a happily retired dentist, living in a pleasant sunny town. We know a priori that he is an excellent investor, and that he will be expected to earn a return of 15% on excess of treasury bills, with a 10% error rate per annum.
That means that out of 100 sample paths (from the simulation), we expect 68 of them to fall within a band of plus and minus 10% around the 15% excess returns i,e. between 5% and 25% (this is based on the fact that in a simple binomial distribution 68% of all observations fall within +/- 1 standard deviation of the mean)
It also means that 95 sample paths (from the simulation) would fall between -5% and 35%
The dentist builds for himself a nice trading desk in his attic, aiming to spend every business day there watching the market, whilst sipping decaffeinated cappuccino. He as an adventurous temperament so he finds this activity more attractive than drilling the teeth of reluctant little old park avenue ladies.
He subscribes to a web based service that supplies him with continuous prices, now to be obtained for a fraction of that he pays for his coffee. He puts his inventory of securities in his spreadsheet and can thus monitor the value of his speculative portfolio.
A 15% return, with a 10% volatility (or uncertainty) per annum translates into a 93% probability of making money in any given year. But at a narrow time scale this translates into a mere 50.02% probability of making money over any given second.
Over very small time increments, the the observation will reveal close to nothing. Yet the dentists heart will not tell him that. Being emotional, he feels a pang with every loss as it shows in red on his screen. He feels some pleasure when the performance is positive, but not in equivalent amount as the pain experienced when the performance is negative [Talab covers this point in considerably more detail later in the book]
At the end of every day, the dentist will be emotionally drained. A minute by minute examination of his performance means that each day (assuming 8 hours per day) he will have 241 pleasurable minutes, against 239 un-pleasurable ones, and this amounts to 60,688 and 60,271 respectively per year.
The table below shows the probability of making a profit over a given period of time:
Period Probability
1 Year 93%
1Quater 77%
1 Month 67%
1 Day 54%
1 Hour 51.3%
1 Minute 50.17%
1 Second 50.02%
Consider the situation where the dentist examines his portfolio only upon receiving his monthly account from the brokerage house. As 67% of his months will be positive, he only incurs four pangs of pain per annum and eight uplifting experiences. This is the same dentist following the same strategy. Now consider the dentist looking at his performance only every year. Over the next 20 years that he is expected to live, he will experience 19 pleasant surprises, for every unpleasant one.
The scaling property of randomness is generally misunderstood even by professionals. I have seen PhD’s argue over a performance observed in a narrow time-scale (meaningless by any standard)
- Over a short time increment one observes the variability of the portfolio , not the returns, In other words, one sees the variance, little else. I always remind myself that what one observes is at best a combination of variance, and returns, not just returns
2)Our emotions are not designed to understand the point. The dentist did better when he dealt with monthly statements rather than more frequent ones. Perhaps it would be even better for him if he limited himself to yearly statements
- when I see an investor monitoring his portfolio with live prices on his cellular telephone or his palm pilot, I smile and smile.
Finally I reckon that I am not immune to such an emotional defect, but I deal with it by having no access to information, except on rare circumstances. Again I prefer to read poetry. If an event is important enough it will find its way to my ears."
The key point he’s trying to make is that the distribution in returns is random, and measuring returns over a period as short as a day is meaningless. The idea of earning a consistant 1% a day is an unrealistic expectation that you need to deal with, daily gains and losses are just varience, and not something to get fixated on.