Peter Drucker

The most dangerous mistakes are never made as a result of the wrong answers. Why? The wrong answer to the right question is quickly discovered. 

Said Drucker: "If your answer produces the wrong, unexpected result, you can correct the outcome, especially if you build in feedback from actual results... in other words, a wrong answer to the right problem can, as a rule, be repaired and salvaged."

"The truly dangerous thing is asking the wrong questions and getting the right answers."

"The right answer to the wrong question takes a lot longer to discover and usually leads to more costly errors."

"When it comes to continuous improvement the important and difficult job is never to find the right answer, it is to find the right question."