I have seen too many traders that randomly add condition after condition to their trading strategy, hoping that it will increase their hitrate. What they are trying to do is to add assumption after assumption to their hypothesis, until their hypothesis (“price will move in to this or that direction for this or that amount”) is hopefully correct more often than not.
Going this way usually ends in paralysis through analysis or in total chaos because there are so many conditions when entering a trade that it is impossible for a human brain to follow the system, thus inducing mistakes.
Enter: Occam’s Razor
Occam was one of those scholastic philosophers, living around 1300 A.D. He developed a principle called Occam’s Razor which states that “among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected. Other, more complicated solutions may ultimately prove to provide better predictions, but—in the absence of differences in predictive ability—the fewer assumptions that are made, the better.” But Occam was not the first, even Aristotle, who was living a mere 2000 years ago, theorized about this concept.
Now the thing is that of course when you add or remove certain conditions to your trading strategy, the predictive ability of your strategy will vary thus rendering Occam’s Razor seemingly invalid. Seemingly. Because trading is a game of incomplete information, we can never exactly know the predictive ability of a model.
Even after testing thoroughly, we will always only get an estimate (our winrate). Because of this fact you should base your trading strategy on as few assumptions as possible. (more…)