Backtesting Bias
Backtesting bias refers to the systematic errors that lead to overly optimistic performance projections in a simulated trading environment. Common forms include look-ahead bias, where the model uses information that would not have been available at the time of the trade, and transaction cost neglect, which ignores the impact of slippage and commissions.
In the context of derivatives, failing to account for margin requirements, funding rates, or the difficulty of executing large orders can lead to significant discrepancies between backtest results and live performance. Furthermore, survivor bias ⎊ excluding assets that went to zero ⎊ can severely skew historical results.
Eliminating these biases is a foundational step in quantitative research. A realistic backtest must accurately replicate the execution environment, including the constraints of the exchange's order book and the reality of latency, to provide a true picture of potential profitability.