The duration task estimation is a challenge target to the project team. It does not has neither fixed rules nor clear assumptions to follow, it is related to task resources allocation, and could vary from person to another and from project to another. (Wysocki 2012)
Estimate Activity Duration using Three‐Point Estimates (PERT) The accuracy of the activity duration estimate can be improved by considering estimation uncertainty and risk.This concept originated with the Program Evaluation and Review Technique PERT. Pert Definition According to Wikipedia The Program (or …