PERT Technique for Uncertainty in Project Management

PERT (Program Evaluation Review Technique)

• PERT is a project management technique used to estimate activity durations and project completion times, incorporating uncertainty into the estimations.
• PERT requires three estimates for each activity:
  • Most Likely Time (m): The most probable duration for the activity.
  • Optimistic Time (a): The shortest possible time for the activity, assuming everything goes exceptionally well.
  • Pessimistic Time (b): The longest possible time for the activity, assuming significant delays and challenges.

PERT Assumptions and Calculations

• PERT assumes that activity durations follow a beta distribution, which allows for incorporating uncertainty.
• Expected Time (te): (a + 4m + b) / 6
• Standard Deviation (s): (b - a) / 6

Activity Dependencies and Chain Duration

• Activities arranged in a chain imply that each activity depends on the completion of the previous activity.
• The expected duration of the chain is the sum of the expected times for each activity.
• The standard deviation for the chain is calculated as the square root of the sum of the squared standard deviations for each activity.

Assessing the Likelihood of Meeting a Target

• A target date or time frame for completing the project is set.
• Z-Value Calculation: z = (T - te) / s, where T is the target completion time, te is the expected completion time, and s is the standard deviation for the project.
• Z-Value Interpretation: The z-value represents the number of standard deviations the target completion time is away from the expected completion time.

Critical Chain Concept

• The critical chain concept is a project management methodology that addresses potential inefficiencies in traditional project scheduling.
• Traditional project planning often incorporates "safety zones" or buffers, which can lead to inefficiencies.

Learn how to use PERT to evaluate uncertainty in activity durations and project completion times. This technique is used in project management to estimate activity durations and incorporate uncertainty into the estimations.