Colin S. Gray wrote in Modern Strategy back in 1999:

John Boyd deserves at least an honorable mention for his discovery of the ‘OODA loop‘. The loop specifies a process of Observation-Orientation-Decision-Action, allegedly comprising a universal logic of conflict. As a fighter pilot and subsequent investigation of the reasons why USAF F-86 Sabre jets achieved such remarkably favourable kill ratios in combat against MiG15s over North Korea (10 to 1), Boyd found in the OODA loop the essential logic of success in battle. Just as Luttwak’s logic of paradox permeates all levels and kinds of conflict, so Boyd’s loop can apply to the operational, strategic, and political levels of war, as well as to tactics for aerial dogfights. Boyd’s theory claims that the key to success in conflict is to operate inside the opponent’s decision cycle. Advantages in observation and orientation enable a tempo in decision-making and execution that outpaces the ability of the foe to react effectively in time. This seemingly simple tactical formula was duly explained and copiously illustrated historically by Boyd in many briefings within the US defense community over the course of twenty years. The OODA loop may appear too humble to merit categorization as a grand theory, but that is what it is. It has an elegant simplicity, an extensive domain of applicability, and contains a high quality of insight about strategic essentials, such that its author well merits honourable mention as an outstanding general theorist of strategy

Contrast this passage with two passages from Gray’s Another Bloody Century, published seven years later:

Air Force Colonel John Boyd touted a tactical insight derived from personal experience from aerial combat as a general theory  of conflict. His OODA loop, standing for Observation, Orientation, Decision, and Action, is revered by many as summarizing the wisdom of the ages on how to win. The core notion is that success rewards the warrior who can operate within the decision cycle of the enemy. It is a sound idea, but as the philosopher’s stone for victory for victory at all levels of warfare it is distinctly sub-Clausewitzian. A major problem with the OODA loop is that its devotees assume that a tactical insight, even principle, will be no less valid at the operational and strategic levels of warfare. It is fairly clear this is not the case.

…and…

As we noted earlier, Colonel John Boyd, USAF fighter pilot turned guru, applied his tactical knowledge of air combat to warfare at all levels  by means of his simple formula of the ‘OODA loop’. Unmatched speed in the sequence of observation, orientation, decision, and action is held to be the key to victory. This insight, banal statement of the obvious, or panacea—take your choice—is probably the most important concept undergirding the current US programme of long-term military transformation. The OODA loop is a formula for decisive success in a manoeuvering style of warfare. American technology, particularly in the realm of the real-time gathering, processing, and diffusion of information, enables US forces to act effectively with a speed that leaves their enemies gasping in their wake. At least, that is the theory.

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