Quantitative Trading, 2nd Edition

CHAPTER 3Backtesting

A key difference between a traditional investment management process and a quantitative investment process is the possibility of backtesting a quantitative investment strategy to see how it would have performed in the past. Even if you found a strategy described in complete detail with all the historical performance data available, you would still need to backtest it yourself. This exercise serves several purposes. If nothing else, this replication of the research will ensure that you have understood the strategy completely and have reproduced it exactly for implementation as a trading system. Just as in any medical or scientific research, replicating others' results also ensures that the original research did not commit any of the common errors plaguing this process. But more than just performing due diligence, doing the backtest yourself allows you to experiment with variations of the original strategy, thereby refining and improving the strategy.

In this chapter, I will describe the common platforms that can be used for backtesting, various sources of historical data useful for backtesting, a minimal set of standard performance measures that a backtest should provide, common pitfalls to avoid, and simple refinements and improvements to strategies. A few fully developed backtesting examples will also be presented to illustrate the principles and techniques described.

COMMON BACKTESTING PLATFORMS

Numerous commercial platforms are designed for backtesting, ...