Roy Schulte wrote an interesting article about it. “Real time is whatever you need it to be, but with an eye toward speed and using some reasonable constraints. In both engineering and business, real time is all about acting in the “right time” for that particular process. You need to identify the point of diminishing returns where going faster doesn’t improve the results or where the costs of going faster outweigh the benefits of going faster. Real time refers to the duration of the end-to-end process from the observation of new information to the execution of the response. It’s often useful to analyze a process using the observe-orient-decide-act (OODA) loop” Link