PERT Program Evaluation and Review Technique

PERT stands for Program Evaluation and Review Technique. This comes under time management and scheduling. It provides more accurate estimation as it takes care of the best case and the worst case. Best case is the optimistic view and the worse case is the pessimistic view.


PERT Formula
ET = (P + 4*M + O)/6

Where:
ET = Expected time
P = pessimistic value
M = Most Likely Value
O = Optimistic value

A project normally will take 12 days to finish but if every thing goes well then it finish in 10 days. Worst case scenarios is that it will finish in 26 days if things do not go well.
O = 10 days as it is the optimistic time.
M = 12 days as most likely likely it will take 12 days to finish.
P = 26 days as this worst case scenario.

ET = (26 + 4*12 +10)/6
= (26 + 48 + 10)/6
= 84/6 = 14 Days

So expected time to finish this activity will be 14 days.