📘 Network Analysis and Critical Path Analysis (CPM)
🔹 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)
🔹 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.
🔸 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
🔸 Key Steps in Network Analysis
1. Forward Pass ➡️
-
Calculates:
- Earliest Start (ES)
- Earliest Finish (EF)
EF = ES + Duration
2. Backward Pass ⬅️
-
Calculates:
- Latest Finish (LF)
- Latest Start (LS)
LS = LF − Duration
3. Slack Calculation ⏱
- Extra time available for an activity
Slack = LS − ES OR LF − EF
4. Critical Path Identification ⭐
- Path with zero slack activities
🔹 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
🔸 Critical Path Meaning
- The longest duration path
- Contains critical activities only
- Any delay in this path → delays entire project
🔸 Formula Idea
Project Duration = Sum of durations on Critical Path
🔸 Steps in Critical Path Analysis
🔹 Step 1: Draw Project Network
- Show all activities and dependencies
🔹 Step 2: Assign Time Estimates
- Each activity gets a duration
🔹 Step 3: Find All Possible Paths
- List all start-to-end paths
🔹 Step 4: Calculate Path Durations
- Add activity times for each path
🔹 Step 5: Identify Longest Path
- Longest path = Critical Path
🔹 Step 6: Find Slack
- Non-critical activities may have float
🔸 Example
| Path |
Duration |
| A → B → D |
10 days |
| A → C → D |
8 days |
👉 Critical Path = A → B → D
👉 Project Duration = 10 days
🔹 4. Diagram Description
A project network diagram typically shows:
- 🟦 Nodes = Activities
- ➡️ Arrows = Dependencies
- 🔢 Numbers = Duration
- ⭐ Highlighted path = Critical Path
🔹 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 |
🔹 6. Importance
- Helps in accurate project scheduling
- Identifies critical tasks
- Prevents project delays
- Improves resource allocation
- Supports decision-making in project control
🔹 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
🔹 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.
🔹 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.
🔹 10. Likely Exam Questions
- Define network analysis.
- What is critical path analysis?
- Explain forward and backward pass.
- What is slack in network analysis?
- Differentiate between network analysis and critical path analysis.
- Why is the critical path important?
- Draw and explain a project network diagram.