In his book The Business of Economics John Kay writes:

For centuries, the subject of medicine was mostly nonsense. [footnote omitted] Doctors applied fashionable nostrums, sometimes bleeding their patients, sometimes starving them. Generally these remedies were useless, sometimes they were fortuitously beneficial, at other times unintentionally harmful. States of health were defined by reference to ascientific categorization, such as the humours of the elements. The prestige of a doctor rested more on the status of his patients and the confidence of his assertions than on the evidence of his cures.

The parallels with management are obvious, if not exact, and the reasons for the parallels are obvious too. Both medicine and management deal with urgent and pressing problems. The demand for a cure is so pressing that critical faculties are suspended. The quack who promises relief often receives a warmer welcome than the practitioner who recognizes the limitations of his own knowledge, and since it is difficult to measure the effectiveness of treatment, this impression may persist after it is over.