The idea that using a methodology that suits your personality is an essential component of trading success also helps explain why most people lose money using trading systems they bought. Why is that true? Is it because most trading systems don’t work on data not used in their development? I am not implying that.Actually, I have no idea what percentage of trading systems sold to the public provide a market edge. But even if I assumed that more than 50 percent of the systems sold would be profitable if applied as instructed, I would still expect over 90 percent of the buyers of those systems to lose money trading them.
Why? Because every trading system, regardless of the strategy employed, is going to hit periods when it does poorly. Now, if you buy a system, by definition, it has nothing to do with your personality or beliefs.In many, if not most, cases, you won’t even have any idea what drives the system’s signals. Consequently,the first time the system hits a bad period, you are not going to have the confidence to stay with the system,and you will stop trading it. That is why, invariably, most people who buy systems will end up losing:
They will stop using the system when it goes through a bad period, and they won’t be there when the system recovers.