Core terms
Hindsight bias
The tendency, once an outcome is known, to see it as more predictable than it was at the time.
Fischhoff (1975) showed that people told an outcome overestimate how likely they would have judged it beforehand. Chart examples are especially exposed: labels such as "the low of the day", "the breakout" or "the perfect entry" can only be applied after later bars have printed.
A practical test for any chart caption or study condition: was this knowable at the decision time? If it needs data from after the decision (later bars, the day's close, the high of day), it is hindsight, however clear it looks on the finished chart.
What traders should verify
In reviews and practice logs, keep a column for "knowable at the decision time" and write it from the bars visible then, not from the finished chart. Treat conditions that use later information as descriptions of a day, not as entry criteria.
Do not conflate
Hindsight is not the same as dishonesty; most chart examples are posted in good faith. The bias comes from seeing the ending first.
Primary source
Primary sourceFischhoff, 1975