1. An observable action, occurrence, or a change in condition.
  2. A change in knowledge about a condition, even if the condition did not change.


  1. A change in condition is easily understood to be an event. However, it is also important to note that a change in knowledge about a condition is also an event. For example, an organization did not know that a facility was built on top of weak earth. Once this is discovered, and event occurs. The condition did not change. However, the organization’s knowledge about the condition did change.