Uncertainty in Project Scheduling
During project execution, however, a real-life project will never execute exactly as it was planned due to uncertainty. It can be ambiguity resulting from subjective estimates that are prone to human errors or it can be variability arising from unexpected events or risks. The main reason that PERT may provide inaccurate information about the project completion time is due to this schedule uncertainty. This inaccuracy is large enough to render such estimates as not helpful.
One possibility to maximize solution robustness is to include safety in the baseline schedule in order to absorb the anticipated disruptions. This is called proactive scheduling. A pure proactive scheduling is a utopia, incorporating safety in a baseline schedule that allows to cope with every possible disruption would lead to a baseline schedule with a very large make-span. A second approach, reactive scheduling, consists of defining a procedure to react to disruptions that cannot be absorbed by the baseline schedule.
Read more about this topic: Program Evaluation And Review Technique
Famous quotes containing the words uncertainty and/or project:
“It was your severed image that grew sweeter,
That floated, wing-stiff, focused in the sun
Along uncertainty and gales of shame
Blown out before I slept. Now you are one
I dare not think alive: only a name
That chimes occasionally, as a belief
Long since embedded in the static past.”
—Philip Larkin (1922–1986)
“Music is so much a part of their daily lives that if an Indian visits another reservation one of the first questions asked on his return is: “What new songs did you learn?””
—Federal Writers’ Project Of The Wor, U.S. public relief program (1935-1943)