Program Evaluation and Review Technique (PERT) is a network analysis technique used to estimate project duration when there is uncertainty about activity durations. PERT uses probabilistic time estimates based on optimistic, most likely, and pessimistic durations to account for risk. It involves developing schedules that are more realistic than critical path method (CPM) alone by considering multiple duration estimates for each activity. PERT can determine expected total time, activity start and end times, critical paths, how delays affect completion, and the probability of on-time completion.

1. Program Evaluation and Review
Technique (PERT)
PERT, IT Project Management
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Faculty Coordinator: Dr. Vibha V
BMS College of Engineering

2. Program Evaluation and Review Technique
(PERT)
 PERT is a network analysis technique used to estimate project duration
when there is a high degree of uncertainty about the individual activity
duration estimates
 PERT uses probabilistic time estimates
 Duration estimates based on using optimistic, most likely, and pessimistic
estimates of activity durations, or a three-point estimate
 PERT attempts to address the risk associated with duration estimates by
developing schedules that are more realistic
It involves more work than CPM since it requires several
duration estimates
PERT, IT Project Management 2

3. Program or Project Evaluation
and Review
Technique(PERT)
PERT, IT Project Management 3

4. CPM / PERT
• Both approaches use a network representation to display the relationships
between project activities and to help managers to
address questions such as
• 1. What is the total time required to complete the project (the expected total
time for
PERT)?
• 2. What are the start and the completion times for individual activities?
• 3. Which critical activities must be completed as
scheduled to meet the estimated project completion time?
• 4. How much delay can be tolerated for non-critical activities without
incurring a delay in the estimated project completion time?
• 5. What is the least expensive way to speed up a project to meet a targeted
completion time? PERT also provides answers to the following additional
questions
• 6. What is the probability of completing a project within a given time frame?
• 7. What is the variability in
the project completion time?
PERT, IT Project Management 4

5. PERT Formula and Example
• PERT weighted average =
optimistic time + 4X most likely time + pessimistic time
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• Example:
PERT weighted average =
8 workdays + 4 X 10 workdays + 24 workdays = 12 days
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where optimistic time= 8 days,
most likely time = 10 days, and
pessimistic time = 24 days
Therefore, you’d use 12 days on the network diagram instead of 10 when
using PERT for the above example
PERT, IT Project Management 5

6. The following table shows the
jobs of a network along with
time estimates
Activity Estimated Duration
Optimistic
Most
Likely Pessimistic
1-2 1 7 13
1-6 2 5 15
2-3 2 14 26
2-4 2 5 8
3-5 7 10 19
4-5 5 5 17
6-7 5 8 29
5-8 8 3 9
7-8 8 17 32
PERT, IT Project Management 6

7. Task
 Draw Project Network
 Find the expected time and variance of each activity
 Calculate the earliest and latest occurrences of each event
 Calculate expected project length
 Calculate variance and standard deviations of project length
 Fine the probability of the project completing in 40 units of time.
PERT, IT Project Management 7

8. Estimated activity time
(To+4Tm+Tp)/6
Activity Estimated Duration
Optimist
ic
Most
Likely
Pessimi
stic Te
1-2 1 7 13 7
1-6 2 5 15 6
2-3 2 14 26 14
2-4 2 5 8 5
3-5 7 10 19 11
4-5 5 5 17 7
6-7 5 8 29 11
5-8 8 3 9 5
7-8 8 17 32 18
PERT, IT Project Management 8

9. Draw the network diagram
PERT, IT Project Management 9
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2 5
6
3
4
7
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10. PERT, IT Project Management 10

11. PERT, IT Project Management 11