The whole idea behind using a computer to do the back-testing is to remove the human aspect from the test.
Which one may want to do if he is backtesting an indicator-based system. But judging from your charts, this is not what you're trying to do (though you do plot an EMA which is preventing you from taken the proper entries). If you were trying to backtest such a system via computer, I'd say go ahead, even though you'd have to do it all over again at some point in the future, most likely some near point.
A system based on price movement does not require constant maintenance because price is self-correcting. But this has all been hashed out in the If You Could Go Back In Time thread, with NoDoji and me and a few others against the world.
If you want to "remove the human aspect" from backtesting, and by that I assume you mean that you don't want to have to interpret trader behavior in order to determine probabilities and make judgements regarding trading decisions, then you've chosen the wrong approach. The "human aspect" is what trading price is all about. If you have no interest in that, then plot a MACD and an RSI and a slosto and begin again.
If one sees that over time the maximum consecutive losses is X then a proper position size can be arrived at to avoid running out of money.
Not if that maximum happens to exceed itself, which it may well do since markets are unpredictable. Even so, with what does one begin again after his resources have been depleted by that maximum number of consecutive losses?
Remember that this whole notion of "positive expectancy" was developed by someone who couldn't trade profitably, but failing traders have latched onto it like ticks because it provides the allure of being able to pursue a losing strategy and yet eventually show a profit, sort of like the promise of the afterlife. Unfortunately for those traders, it's nonsense. If one doesn't have a winrate considerably better than that 30% so regularly touted, he's going to go broke. Even 50% will be a trial without spectacular trade and risk management, each of which is rare among traders and practically non-existent in combination.
Of course a Black Swan event can happen and the 2007 economic crisis is one example.
An example of what? That decline was easily predictable. In fact, I sold my house in Phoenix in spring of '08, and not due to indicators but rather plain ol' price charts.
To quote you, "Gold."
Gabe is half right. You can make money with a system that has a 30% win rate. In fact, that is the typical win rate of trend following systems, eg volatitlity breakout, moving average systems, etc. What he is missing however is that these types of systems rely on a handful of enormous winners. You are not going to get those winners if you are exiting every time price ticks against you, or at the end of the day for that matter. I studied intraday stock index systems for a long time and concluded that there were no commercial systems that were reliably profitable. None.
The other thing about low win rate systems is that they are best traded by someone who is trading them across a portfolio of commodities, not just one market. Like Cramer says, there is always a bull market somewhere. You might wait years for one to come to the one market you are trading. Even across a portfolio of tradeables, these systems have huge drawdowns, meaning you need a big bankroll and a lot of patience and trust.
If you are trading intraday, you need a decent win percentage. You also need a way to let profits run without giving back too much.