The hardest and most significant part of system trading is managing them.
Quote from jwecme:
I am an unsuccessful trader of ES having wasted years on mechanical systems. I back tested them intraday for months trying juts about everything under the sun to get them to work. I realised after reading Fooled by Randomness of the folly of my actions. You can always back test to data and skew the variables to produce a profitable result.
The reality I have discovered to my cost is that trading is far more complex and awkward than even the best mechanical system can cope with. It's effectiveness seems to be proportional to the time frame i.e. the shorter the time frame the less effective the results. Intraday I contend that it is useless.
If anybody disagrees I would love to hear your opinions. So many people say I have found âTHEâ system then go strangely quiet as they see the dreadful results that occur over time by itsâ application.
Profitable intraday trading is possible through hard work, exp and flexibility not through a secret system or market key! Cue abusive responses.....
Quote from mokwit:
This, excerpted from a an Amazon review of The Logical trader by trader75 (ET name is different) sums up a lot for me........
As PTJ noted in Market Wizards, all forms of trading are ultimately systematic. Every human decision is based on some form of logic, conscious or otherwise, even if the `logic' in question is nothing more than base fight-or-flight response. So when you think about it, a trader really has three options when it comes to developing a methodology:
1) He can hack away and reinvent the wheel on a regular basis, making arbitrary decisions over and over without examining them or even being consciously aware of them. This is otherwise known as beating your head against the wall.
2) He can develop a system `in his head' through years of trial and error + costly experience, purging mistakes through sheer repetition and dogged determination. This is learning the hard way (maybe the hardest way), unless one has the good fortune of an excellent teacher / mentor at hand.
3) He can consciously commit to the development of a robust 'system'--be it discretionary, mechanical or a blend of both--recognizing the need for structure and articulated reasoning. Through a deliberate process, mistakes are analyzed and rules reviewed with an eye for consistency and improvement over time, allowing the methodology to evolve into something sound and useful.
Mark Fisher's gift, in addition to the ACD system itself, is clarifying by example how vital it is for a trader to reach level three. In creating a flexible structure and abiding by a clear set of rules, the discretionary trader ultimately finds himself liberated. As good brakes on a Porsche enable more speed on curvy mountain roads, intelligent trading guidelines enable more freedom and versatility rather than less.
Why? Because when the method of operation is defined and systematized, the core elements no longer require conscious thought--or very little conscious thought--to execute in real time. Given enough familiarity and conviction, the basic workings of the method no longer take up valuable real estate in the conscious mind; instead, the rules are 'unpacked' into the vast airplane hangar of the subconscious. With the conscious mind no longer burdened by a need to reinvent the wheel / make arbitrary decisions / create structure on the fly, stress levels go down and awareness levels go up. It becomes easier to pay more attention to subtleties, take in more information, analyze more markets, engage in further R&D, or simply trade in a more relaxed and confident way.
Quote from jwecme:
If anybody disagrees I would love to hear your opinions. So many people say I have found âTHEâ system then go strangely quiet as they see the dreadful results that occur over time by itsâ application.

Quote from RoughTrader:
Coming to this understanding is a great step towards reaching success in trading these markets.
Markets can be terribly efficient on an intraday basis. When looking on timeframes of 5, 15, 30, 60 minutes, the markets do a wonderful job of twisting and turning to make finding tradable biases few and far between.
I wouldn't say that it is useless by any means. I trade all four e-mini indexes intraday profitably with purely mechanical rules. However, it should be known that much of the time will be spent trading noise if one does not identify times where a bias is present versus not present. It is far easier to trade biases present on longer time frames, such as daily and weekly instead.
RoughTrader