RESOURCES / BACKTESTING FOUNDATION
Portfolio Backtest Methodology and Data
The same visible rules should always produce the same result from the same version of the data.
Deterministic calculation
AI can structure questions and explain differences, but return series, rebalancing, costs, and risk metrics are calculated by deterministic code.
Data lineage
Every comparison should identify its source series, adjustment rules, substitution record, coverage dates, and data version.
Reproducibility
Published studies retain their portfolio rules, assumptions, engine version, and result fingerprint so another user can reproduce the comparison.