All traders who use some form of technical analysis (i.e. chart-reading) rely on the underlying rationale that there are patterns embedded within the seemingly random ups and downs in the price movements. Somehow, we have to believe that there is order within chaos. Certainly, the existence of such order is what we rely on in order to have a trading method which gives us an edge over the market.
However, all too often, our attempts to discover patterns are overdone. The human mind is created to recognise patterns within chaos, causing us to be too eager and hasty in coming to conclusions about certain patterns on the charts. As we eye-ball the historical charts, we will certainly be able to to find many profitable trades based on some technical conditions, thereby leading us to arrive at a strategy. The thing is that our eyes are under the influence of selective perception, i.e. we tend to see the trades that work, and visually bypass those that don’t. The technical analyst is often deluded by illusions of order.
In this way, the trading rules that one arrives at tend to be too simplistic. The market is so dynamic that we often need to apply some filters to the trading rules; such filters cannot be clearly seen in our “visual backtesting”.
Another thing to note is that correlation does not imply causality. This means that the often-noticed phenomenon that two currency pairs tend to move in tandem does not imply that movements in one of the pairs “causes” movements in the other. Any strategy based on assumptions of causality cannot work consistently.
We should be reminded that although there are patterns within the ups and downs of crowd psychology in any liquid market, such patterns do not exist like they do in an exact science (e.g. laws of physics), and are therefore still full of randomness. This is the reason why we should make allowances for losses in all trade decisions (regardless of how we filter trading signals); such losses occur when the “randomness within patterns” works against us. The fact that such losses occur from time to time does not mean that we don’t have an edge over the market. Having an edge over the market means that in the long run, the wins will more than cover the losses. Much of the diffilculty in trading is learning to accept this simple principle.
Too many traders simply overlook or gloss over the importance of discipline and stringent risk management. When we consistently keep to the rules despite losses, and keep losses to a minimum via stringent risk management, any simple strategy that gives us an edge will be profitable in the long run.