📘 Network Analysis and Critical Path Analysis (CPM)

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🔹 1. Introduction

In Software Project Management, project scheduling is done using a project network, which shows activities and their dependencies.

Two important techniques used on this network are:

• 📊 Network Analysis
• ⭐ Critical Path Analysis (CPA / CPM)

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🔹 2. Network Analysis

🔸 Definition

Network Analysis is the process of studying a project network to determine project schedule, activity timings, dependencies, slack, and resource planning.

👉 In simple words: It helps us understand how the project flows and how long it will take.

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🔸 Objectives of Network Analysis

• Determine project completion time
• Identify start and finish times of activities
• Find slack (float)
• Improve resource utilization
• Support project monitoring and control

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🔸 Key Steps in Network Analysis

1. Forward Pass ➡️

• Calculates:

  • Earliest Start (ES)
  • Earliest Finish (EF)

EF = ES + Duration

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2. Backward Pass ⬅️

• Calculates:

  • Latest Finish (LF)
  • Latest Start (LS)

LS = LF − Duration

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3. Slack Calculation ⏱

• Extra time available for an activity

Slack = LS − ES OR LF − EF

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4. Critical Path Identification ⭐

• Path with zero slack activities

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🔹 3. Critical Path Analysis (CPA / CPM)

🔸 Definition

Critical Path Analysis (CPA) is a technique used to identify the longest path of dependent activities in a project network, which determines the minimum time required to complete the project.

👉 Also known as Critical Path Method

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🔸 Critical Path Meaning

• The longest duration path
• Contains critical activities only
• Any delay in this path → delays entire project

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🔸 Formula Idea

Project Duration = Sum of durations on Critical Path

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🔸 Steps in Critical Path Analysis

🔹 Step 1: Draw Project Network

• Show all activities and dependencies

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🔹 Step 2: Assign Time Estimates

• Each activity gets a duration

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🔹 Step 3: Find All Possible Paths

• List all start-to-end paths

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🔹 Step 4: Calculate Path Durations

• Add activity times for each path

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🔹 Step 5: Identify Longest Path

• Longest path = Critical Path

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🔹 Step 6: Find Slack

• Non-critical activities may have float

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🔸 Example

Path	Duration
A → B → D	10 days
A → C → D	8 days

👉 Critical Path = A → B → D 👉 Project Duration = 10 days

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🔹 4. Diagram Description

A project network diagram typically shows:

• 🟦 Nodes = Activities
• ➡️ Arrows = Dependencies
• 🔢 Numbers = Duration
• ⭐ Highlighted path = Critical Path

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🔹 5. Difference: Network Analysis vs Critical Path Analysis

Feature	Network Analysis	Critical Path Analysis
Scope	Entire project network study	Focus on longest path
Output	ES, EF, LS, LF, slack	Critical path & project duration
Purpose	Scheduling & control	Identify project completion time
Complexity	Broader	Specific technique

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🔹 6. Importance

• Helps in accurate project scheduling
• Identifies critical tasks
• Prevents project delays
• Improves resource allocation
• Supports decision-making in project control

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🔹 7. Key Exam Points

• Network analysis = full study of project schedule
• CPA/CPM = finding critical path
• Critical path has zero slack
• Delay in critical path → project delay
• Used in CPM & PERT techniques

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🔹 8. Short Summary

• Network Analysis studies the entire project schedule using forward and backward pass techniques.
• Critical Path Analysis identifies the longest path that determines project duration.
• Both are essential for planning, scheduling, and controlling software projects.

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🔹 9. Quick Exam Answer (2–3 lines)

Network analysis is the process of studying a project network to determine activity timings, slack, and scheduling details. Critical path analysis identifies the longest sequence of activities that determines the minimum project completion time.

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🔹 10. Likely Exam Questions

1. Define network analysis.
2. What is critical path analysis?
3. Explain forward and backward pass.
4. What is slack in network analysis?
5. Differentiate between network analysis and critical path analysis.
6. Why is the critical path important?
7. Draw and explain a project network diagram.