All military operations are attended by various forms of risk. Risk permeates the fabric of war from the actions of individual soldiers, sailors, and airmen to the policies, strategies, and decisions of national leaders. Decisions and actions have both potential and real consequences, and intelligent decision making normally involves a calculation of the odds for success and failure, as well as consideration of the consequences of potential failure. When success is less than a sure thing but through analysis of the salient aspects of the problem, including costs and consequences of failure, a commander decides to proceed nonetheless, we can say that he is taking a “calculated risk.”
Rubel, Robert C.
"Deconstructing Nimitz’s Principle of Calculated Risk,"
Naval War College Review: Vol. 68
, Article 4.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol68/iss1/4