PERT and Three-Point Estimates by PMI

So easy to use!

Three-point estimates are based on determining three types of estimates: Optimistic, Most likely and Pessimistic.

* Most likely(M): The duration of the schedule activity, given the resources likely to be assigned, their productivity, realistic expectations of availability for the schedule activity, dependencies on other participants, and interruptions.

* Optimistic(O): The activity duration is based on a best-case scenario of what is described in the most likely estimate.

* Pessimistic(P): The activity duration is based on a worst-case scenario of what is described in the most likely estimate.

The PERT(Program Evaluation and Review Technique) analysis calculates E - Expected activity duration using a weighted average of these three estimates:

E = (O + 4M + P)/6