Despite careful planning with detailed schedules and fixed completion dates, the complexity and scope of a project may cause delays and other job disruptions.

Terrain, weather, availability of workers, materials and equipment can all affect the rate of completion. When these variables cause inefficiencies in interrelated portions of work, they cause delays as well as the possibility of additional job costs. The term “impact” refers to the string of inefficiencies that are caused by a variable.

Delays, disruptions, interference and acceleration may all be traced back to an event that affected the scheduled work. An analysis of the occurrence determines whether or not there is entitlement to someone for an extension of time. It also determines what, if any, additional costs are associated with the occurrence.