What is Optimistic Time?

Optimistic time is a concept used in the program evaluation and review technique (PERT). It represents the shortest estimated time period within which a task is likely to be completed, and is used in project planning. This estimate should be based on reasonable assumptions, rather than on assumptions that are only theoretically possible. The use of reasonable optimistic time estimates makes it easier to derive realistic project timelines and due dates.

Example of Optimistic Time

A large company has a project task for installing a server in an IT infrastructure project. The task is influenced by factors such as equipment availability, staff expertise, and external vendor support. The time estimates for the installation are as follows:

Optimistic time of 2 days. This assumes that the equipment arrives on time, the technicians encounter no problems, and the configuration is completed flawlessly without needing additional troubleshooting.
Most likely time of 5 days. This assumes that minor delays or standard complications might occur, such as a small learning curve or needing to coordinate between departments.
Pessimistic time of 9 days. This assumes significant delays, such as equipment arriving late, technical difficulties, or vendor unavailability.