{"term":{"slug":"what-is-backtesting","term":"Backtesting","definition":"The process of applying a trading strategy to historical price data to measure how it would have performed in the past. Backtesting quantifies expected win rate, average risk-reward, maximum drawdown, and profit factor before risking real capital on an evaluation.","extendedExplanation":"Backtesting is the most important preparation step before attempting a prop firm evaluation. Without backtesting, traders trade based on intuition and hope -- with backtesting, they know the statistical properties of their strategy: how often it wins, the average size of wins versus losses, the longest losing streak, and the expected drawdown depth. These numbers directly answer whether the strategy can survive a prop firm evaluation.\n\nThere are two main backtesting approaches: manual backtesting (scrolling through historical charts and recording hypothetical trades by hand) and automated backtesting (using platforms like TradingView Pine Script, MetaTrader Strategy Tester, or Python libraries to run code against historical data). Manual backtesting is slower but forces the trader to develop pattern recognition. Automated backtesting covers more data faster but can overfit to historical patterns.\n\nA backtested strategy should be validated against out-of-sample data -- data that was not used during the initial testing period. Many traders backtest on 2020-2023 data, optimize for that period, and then discover the strategy fails on 2024-2025 data because market conditions changed. Testing across multiple market regimes (trending, ranging, high volatility, low volatility) and using at least 200 trades in the sample produces more reliable statistics.","exampleWithNumbers":"Manual backtest of a head and shoulders reversal strategy on EUR/USD 1H, 2022-2024 (2 years). Identified 34 setups. Results: 21 wins (61.8% win rate), average win 68 pips, average loss 40 pips. Profit factor: (21 * 68) / (13 * 40) = 1428 / 520 = 2.75. Maximum consecutive losses: 4 (160 pip cumulative). On FTMO $100K with 1 lot ($10/pip), max consecutive loss = $1,600 -- well within $10,000 drawdown. Expected monthly profit (4 setups/month): 4 trades * (0.618 * $680 - 0.382 * $400) = 4 * ($420 - $153) = $1,068.","category":"strategy","relatedTerms":["strategy-backtesting","win-rate","risk-reward-ratio","drawdown-recovery","evaluation-phase"]},"_links":{"self":"https://runvigil.app/api/glossary/what-is-backtesting","page":"https://runvigil.app/learn/what-is-backtesting","allTerms":"https://runvigil.app/api/glossary","learn":"https://runvigil.app/learn"}}