The concept of reliability is one which can prove to be of paramount importance to the project management team and or the project management team leader, as errors in reliability can cause productivity to decline significantly. Specifically speaking, reliability refers to the probability and or the likelihood that a given product will perform in the way and or manner it was intended to perform in the efforts that have been deemed required of that given product within or under a specific period of time required. Products that have high levels of reliability are preferred for a wide and varied number of reasons. One of the most significant reasons for this is that, when product reliability is higher and or greater it allows for less wasted energy and less redundancy , and allows more members of the project team to focus on additional aspects of the project sooner. Products with lower reliability will cause more wasted energy, and more redundancy.
This term is defined in the 3rd edition of the PMBOK but not in the 4th.