PERT Three-Pont Estimating

Project Management: PERT Three-Point Estimating#

If you are estimating the duration of a project or task, PERT stands for Program Evaluation and Review Technique. It calculates a weighted average of three time estimates to account for real-world uncertainty.

The formula is:#

$E = \frac{O + 4M + P}{6}$

• O (Optimistic): The best-case scenario if everything goes perfectly.
• M (Most Likely): The expected duration under normal, everyday conditions.
• P (Pessimistic): The worst-case scenario if everything goes wrong.

Example#

If it takes your team:

• 3 days in the best case,
• 5 days normally,
• 13 days in the worst-case scenario,

then your PERT estimate is:

$E = \frac{3 + (4 \times 5) + 13}{6} = \frac{36}{6} = 6\text{ days}$