In their decision-making activities, managers need to tread a fine line between ill-conceived, arbitrary decisions (“extinction by instinct”) and an unhealthy obsession with number, analyses, and reports (“paralysis by analysis”). The author examines the over- and underuse of formal analysis and describes its underlying motives. She identifies three types of situations that lead to excessive analysis and three that lead to insufficient analysis. She concludes that, since the causes are frequently structural, simply exhorting managers to be more or less analytical is unlikely to solve the problem. Attention must be given to deeper structural and cultural issues. Moreover, because the obvious solution to one problem may drive the organization to the opposite one, rational yet efficient decision making is a complex balancing act that requires frequent diagnosis and realignment.