“I’ve never seen a bad backtest” — Dimitris Melas, head of research at MSCI.
A backtest is a simulation of a trading strategy used to evaluate how effective the strategy might have been if it were traded historically. Backtestesting is used by hedge funds and other researchers to test strategies before real capital is applied. Backtests are valuable because they enable quants to quickly test and reject trading strategy ideas.
All too often strategies look great in simulation but fail to live up to their promise in live trading. There are a number of reasons for these failures, some of which are beyond the control of a quant developer. But other failures are caused by common, insidious mistakes.
An over optimistic backtest can cause a lot of pain. I’d like to help you avoid that pain by sharing 9 of the most common pitfalls in trading strategy development and testing that can result in overly optimistic backtests.
Read the full article on Quantopian at 9 Mistakes Quants Make that Cause Backtests to Lie