NO! You trade a system if, and only if the backtest reveals that it is profitable. Unless you want to trade a losing system with discipline.
Tradex, You make a very good point. Discipline, trading plan, mental stable, risk vs reward is all a losing battle, if it all have not been back tested and reveals profitability.
In a way. Rather than look for instances when the set-up worked, Easy to see on the left hand side of the chart . I looked for when the set-up failed. My limited experience with back testing is that it leads to curve fitting. Forward testing in real time will give you more realistic results. Only after I am convinced a strategy will offer positive expectation will I commit some capital to it. Then comes the discipline. Without trading the system as planned you never know if the problem is the strategy or the trader. It's way easier to adjust the strategy.
That is 1000% correct. And I am experiencing it myself. Lately I have been writing out my entry and trade management and rules on paper. Instead of keeping them in head. And keep stats on each trade setup.
I am talking about backtesting a system with 20 or 30 years of historical data. The trader cannot "test" a system and then calls it "profitable" after 19 trades (for instance), that's a total joke. But believe it or not, that's what a lot of traders do.
Not everyone has an automated system, most of discretionary like mine, so you can't backtest 20-30years of data and even if you did pretty meaningless. I assess my system daily, did I make a profit ?? YES don't fiddle, NO how do I improve it. Today, was a KILL it with FIRE day!
Most traders here rely on automation, see https://www.elitetrader.com/et/threads/poll-automated-trading.346153/