miscalculation

This term describes a failure in judgment or arithmetic that leads to an incorrect conclusion. It carries a connotation of precision gone wrong, suggesting that a process of estimation or counting was performed but executed flawedly. In strategic or social contexts, it implies a blind spot or an overestimation of one's own power or the opponent's weakness. It is often used in formal reports, historical analyses of military failures, or technical post-mortems to describe the specific point where a plan diverged from reality.