Abstract

When a decision ends badly, the reasons given for it change. Psychology names two parts of this change: hindsight bias, the sense, once an outcome is known, that it was always likely (Fischhoff 1975), and outcome bias, rating the same decision on the same information as worse when it ended badly (Baron and Hershey 1988). Methods that score forecasts against what happened, over many forecasts, offer a different test (Brier 1950; Tetlock 2005). The sociology of organisations doubts the remedy both lines need, the record written before the decision, because such records can defend their authors or persuade an audience that risk is in hand (Power 2004; Clarke 1999). This article sets the three positions beside a nineteenth-century telling of a financial collapse: the chapter on the South Sea Bubble in Charles Mackay's Extraordinary Popular Delusions (1841), read in the London edition of 1852, as a record of how the episode was told and not as a source of facts or figures. Mackay's narrative turns a warning into prophecy, judges the directors by the ruin before their guilt was established, and still preserves, in quoted letters, a dissenting memoir and a later footnote, the material for telling it differently. Two synthetic decision records published by WSTiger, a studio of the RISCON family, set the same problem in a 1956 voyage and a 2026 trading desk. Read beside Mackay, they show what a reason written before the outcome protects and what it cannot settle. The article does not decide which standard of judgment is right.