Articles

Introduction In this article we'll take a look at two related practices that are widely used by traders called Backtesting and Data Mining. These are techniques that are powerful and valuable if we use them correctly, however traders often misuse them. Therefore, we'll also explore two common pitfalls of these techniques, known as the multiple hypothesis problem and overfitting and how to overcome these pitfalls. Backtesting Backtesting is just the process of using historical data to test the performance of some trading strategy. Backtesting generally starts with a strategy that we would like to test, for instance buying GBP/USD when it crosses above the 20-day moving average and selling when it crosses below that average. Now we could...

In the first part of this article, which can be read here, we looked at choosing an instrument and timeframe to trade, as well as establishing the set-up and entry rules. In the second and final part we will consider how to establish exit rules as well as various filters and money management rules to maximise the profitability of the system. 6. Stop Loss Rules. Our strategy already has a natural stop loss in the stop order that does not get filled. The objective of the strategy is to capitalise on those days where the high or low for the day is in place early (9.30-11.45am). If we enter a trade on a breakout of either the high or the low and then the market subsequently hits the other stop we know that our trade is invalid. We know...