The project management phrase network open end refers specifically to any particular schedule activity that occurs and takes place in an instance in which no preceding or predecessor activities take place in that series of events. However there are other conditions that must be met in the case of a network open end. In the case of a network open end, also requisite is the existence of absolutely no succeeding events. As a result of the existence of no preceding events and no succeeding events, the result is a single stand alone event that results in the creation of an unintentional break or lapse in the previously determined schedule network path. The cause of network open ends are multiple, however one of them is often times resultant from a simple lapse in the existence of logical relationships among project components. In more rudimentary terms, network open end scenarios can also result from instances in which a single otherwise unrelated activity is inserted into the process of an ongoing project at a date later than the creation of the network schedule.
This term is defined in the 3rd edition of the PMBOK but not in the 4th.