Project Evaluation and Review Technique "

PROJECT EVALUATION AND REVIEW TECHNIQUE
AND
CRITICAL PATH METHOD
CSE 403
(Information System and design)

PERT
(Project Evaluation and
Review Technique)

Key Concepts of PERT in Critical Path Analysis:
Tasks and Milestones:
PERT identifies all tasks needed to complete the project, along
with their milestones.
Network Diagram:
Tasks are represented in a flowchart format, showing
dependencies between them.
Time Estimates:
PERT uses three time estimates for each task:
Optimistic Time (O): The shortest time to complete a task.
Pessimistic Time (P): The longest time to complete a task.
Most Likely Time (M): The best guess of how long a task will
take.
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Key Concepts of PERT in Critical Path
Analysis:
Expected Time Calculation: The expected time (TE) for
each task can be calculated using:
TE= (O+4M+P) / 6
Critical Path: The critical path is the longest path through
the project network, determining the shortest time to
complete the project. Any delay in tasks on this path directly
affects the project completion time.
Slack Time: This refers to the amount of time a task can be
delayed without affecting the overall project schedule. Tasks
on the critical path have zero slack.
3

Benefits of Using PERT
* Helps in planning and scheduling
complex projects.
* Provides a visual representation of
project tasks and their interdependencies.
* Allows for better resource allocation by
identifying critical tasks.
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Key Concepts of CPM
Tasks and Dependencies:
CPM identifies all the tasks involved in a project, along with their
dependencies (which tasks must be completed before others can
start).
Network Diagram:
Similar to PERT, CPM uses a network diagram to visually represent
tasks and their relationships.
Duration Estimates:
Each task is assigned a specific duration. Unlike PERT, CPM typically
uses a single time estimate for each task.
Critical Path:
The critical path is the longest path through the project network,
consisting of tasks that cannot be delayed without delaying the
overall project. This path determines the project's minimum
completion time.
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Benefits of Using CPM
Improved Time Management: CPM helps identify the
longest sequence of dependent tasks, allowing project
managers to focus on activities that directly impact project
duration.
Efficient Resource Allocation: By highlighting critical tasks,
CPM enables better planning of resources, ensuring that time
and effort are allocated where they matter most.
Enhanced Project Planning: CPM provides a clear visual
representation of project tasks and their dependencies,
making it easier to plan and communicate timelines.
7

Program Evaluation and
Review Technique (PERT)
VS
Critical Path Method (CPM)
8

Feature PERT CPM
Abbreviation
Stands for Project Evaluation and
Review Technique. Stands for Critical Path Method
Developed By U.S. Navy (1950s) DuPont (1950s)
Purpose
Manage projects with uncertain
durations
Manage projects with predictable
durations
Time Estimates
Probabilistic (Optimistic, Pessimistic,
Most Likely) Deterministic (Single Estimate)
Focus Time variability and project scheduling Time and resource optimization
Time Calculation Expected Time (TE) = (O + 4M + P) / 6 Straightforward calculation of durations
Network Diagram
Activity-on-Arrow (AOA) or Activity-
on-Node (AON) Usually Activity-on-Node (AON)
Critical Path Not explicitly defined Explicitly defined as the longest path
Risk Management
High emphasis due to uncertain time
estimates
Lower emphasis due to deterministic
nature
Sustainability
It is suitable for projects which
required research and development. It is suitable for construction projects.

***The Critical Path Method (CPM) is a project
management tool used to determine the longest
stretch of dependent activities and measure the
time required to complete a project.
*** Critical Path:
The critical path consists of all activities with
zero float. This path dictates the project's
minimum completion time, and any delay in
these activities will delay the entire project.
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***Float, also known as slack, is the amount of time
that you can delay a task without delaying the
project’s overall completion time. In other words, it
indicates how much flexibility you have in scheduling
specific activities.
***Types of Float:
Total Float: The total time that you can delay an
activity without affecting the project completion date.
Free Float: The time that you can delay an activity
without delaying the early start of any subsequent
activities.
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List Activities: Identify all activities required to complete the project and their durations.
Determine Dependencies: Establish which activities depend on others. Create a
network diagram to visualize these relationships.
Calculate Earliest Start (ES) and Earliest Completion (EC):
ES for the first activity is 0.
For subsequent activities, ES = max(EC of all preceding activities).
EC = ES + duration of the activity.
Calculate Latest Start (LS) and Latest Completion (LC):
For the last activity, LC = EC.
For preceding activities, LC = min(LS of all following activities).
LS = LC - duration.
Calculate Float:
Float (or slack) = LS - ES (or LC - EC).
Activities with zero float are on the critical path.
Formula Summary:
ES: Earliest Start
EC: Earliest Completion/Finish = ES + Duration
LS: Latest Start = LC - Duration
LC: Latest Completion/Finish
Float: Float = LS - ES (or LC - EC)
Steps to Find the Critical Path by Critical Path
Method (CPM):
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Critical Path Method (CPM) [Forward Pass]
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CRITICAL PATH: BDHKN
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Project Evaluation and Review Technique "

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