Methodology

Claim labels

Documented means the core claim appears in a primary or strong contemporaneous record. First-person account means a participant described it later. Accounts differ means credible participants disagree. Calculated estimate means the number follows a disclosed formula. Legend means the familiar version outruns the available evidence.

Historical scenarios

Each game sets a cutoff date. The setup may use only information reasonably available by then. The reveal is written separately so later facts cannot leak into the decision frame.

Visitor percentages remain hidden until at least 25 distinct responses. We do not invent a crowd.

Counterfactuals

Every calculation names the asset or index, observation dates, currency, formula, valuation date and important exclusions. A property index is not a house appraisal. A share-price multiple is not a realizable portfolio return unless splits, distributions, dilution, fees and taxes are handled consistently.

Corrections

Material corrections are dated. Prediction originals are immutable; updates and redactions are append-only. A changed claim is not silently rewritten into having always been correct.