Backtesting & researchAdvanced

Backtesting Methodology

Build backtests that avoid common data errors: use point-in-time data and an honest universe, model realistic costs, separate in-sample from out-of-sample evidence, and read performance reports critically for robustness. A backtest tests a rule on history; it does not forecast future results.

Free self-study · reading course3 lessonsAbout 6 min reading

What you will learn

  • Construct a point-in-time dataset and universe that avoids look-ahead and survivorship bias.
  • Model transaction costs and design out-of-sample and walk-forward tests.
  • Interpret performance metrics and run robustness checks before trusting a result.

Before you begin

Working knowledge of returns, volatility and drawdown, and familiarity with simple rule-based strategies such as moving-average crossovers.

Full lesson list

All lessons are freely available. No enrollment or payment is required.

  1. Point-in-Time Data and the Test Universe

    • Timestamp data by when it became known and avoid look-ahead bias.
    • Build a historical universe that includes delisted securities.
    About 2 min reading
  2. Costs and Out-of-Sample Testing

    • Estimate annual cost drag from turnover and per-trade costs.
    • Design an out-of-sample and walk-forward test and count its windows.
    About 2 min reading
  3. Reading Reports and Testing Robustness

    • Interpret core performance metrics and their blind spots.
    • Apply robustness checks, including outlier removal and sensitivity tests.
    About 2 min reading