Schedule Network Analysis

Schedule Network Analysis: A Complete Guide for PMP Exam

Introduction to Schedule Network Analysis

Schedule Network Analysis is a critical project management technique used to develop and optimize project schedules by analyzing the sequence of activities, their durations, resource requirements, and schedule constraints. This technique forms the foundation of time management in projects and is a key component of the PMI-SP certification exam.

Why Schedule Network Analysis is Important

Schedule Network Analysis is essential because it:

• Provides a visual representation of project activities and their relationships
• Identifies the critical path and potential schedule risks
• Helps determine the earliest and latest start and finish times for activities
• Calculates float or slack time available for activities
• Enables resource optimization and constraint analysis
• Serves as a basis for schedule compression techniques like fast-tracking and crashing
• Facilitates what-if scenario analysis for proactive schedule management

What is Schedule Network Analysis?

Schedule Network Analysis is a technique that uses a network diagram to represent project activities and their logical relationships. It applies mathematical analysis to determine the overall project duration, critical path, and scheduling flexibility.

The primary components include:

1. Activity Sequencing: Identifying and documenting the logical relationships between activities

2. Network Diagrams: Visual representations of activities and their dependencies, including:
• Activity-on-Node (AON) diagrams (Precedence Diagramming Method or PDM)
• Activity-on-Arrow (AOA) diagrams (Arrow Diagramming Method or ADM)

3. Dependency Types:
• Finish-to-Start (FS): The most common relationship where a successor activity cannot start until its predecessor finishes
• Start-to-Start (SS): A successor activity cannot start until its predecessor starts
• Finish-to-Finish (FF): A successor activity cannot finish until its predecessor finishes
• Start-to-Finish (SF): A successor activity cannot finish until its predecessor starts

4. Critical Path Analysis: Identifying the sequence of activities that determines the minimum project duration

How Schedule Network Analysis Works

Step 1: Activity Definition
Define all project activities that must be completed to deliver project deliverables.

Step 2: Activity Sequencing
Determine the logical relationships and dependencies between activities.

Step 3: Create Network Diagram
Develop a graphical representation showing activities and their relationships.

Step 4: Estimate Activity Durations
Assign time estimates to each activity based on resource capabilities and availability.

Step 5: Forward Pass Calculation
Calculate the Early Start (ES) and Early Finish (EF) times for each activity, moving from project start to finish.

Step 6: Backward Pass Calculation
Calculate the Late Start (LS) and Late Finish (LF) times for each activity, moving from project finish to start.

Step 7: Float Calculation
Calculate Total Float (TF = LS - ES or LF - EF) and Free Float for each activity.

Step 8: Critical Path Identification
Identify activities with zero total float, which form the critical path.

Step 9: Schedule Analysis and Optimization
Analyze the schedule for risks, resource conflicts, and optimization opportunities.

Key Techniques in Schedule Network Analysis

1. Critical Path Method (CPM): A technique to identify the sequence of activities with zero float that determines the project duration.

2. Program Evaluation and Review Technique (PERT): A statistical method using weighted average duration estimates (Optimistic, Most Likely, Pessimistic).

3. Critical Chain Method (CCM): A technique that focuses on resource constraints and adds buffers to protect the critical path.

4. Resource Leveling: Adjusting the schedule to address resource constraints, often extending the critical path.

5. Schedule Compression:
• Fast-tracking: Performing activities in parallel that would normally be done in sequence
• Crashing: Adding resources to critical activities to reduce duration

Exam Tips: Answering Questions on Schedule Network Analysis

1. Master the Calculations:
• Practice calculating ES, EF, LS, LF, and float for complex networks
• Understand how to identify the critical path based on zero float
• Know how to calculate PERT estimates using the formula (O + 4M + P)/6

2. Focus on Dependency Types:
• Be able to identify and apply the four dependency types (FS, SS, FF, SF)
• Understand how leads and lags modify these relationships
• Know which dependency types are most commonly used (FS is most common)

3. Understand Network Diagram Types:
• Know the differences between PDM/AON and ADM/AOA diagrams
• Be able to interpret both diagram types
• Understand that PDM is more commonly used in modern project management

4. Connect Concepts to Real Scenarios:
• Practice applying network analysis to scenario-based questions
• Be able to interpret how changes to the network affect the schedule
• Understand the implications of changes to critical and non-critical paths

5. Common Exam Traps:
• Pay attention to constraint types (mandatory, discretionary)
• Be careful with float calculations when dealing with multiple paths
• Watch for questions that ask about impacts of changes to the network
• Look for questions about schedule compression techniques and their impacts

6. Remember Key Formulas:
• ES + Duration = EF
• LS + Duration = LF
• Total Float = LS - ES (or LF - EF)
• Free Float = ES of successor - EF of activity - lag
• PERT = (O + 4M + P)/6
• Standard deviation = (P - O)/6

7. Practical Tips:
• Draw small network diagrams for complex questions
• Eliminate impossible answers first
• Cross-check your calculations
• If stuck, think about the fundamental principles of network analysis

By mastering Schedule Network Analysis, you'll be well-prepared to handle time management questions on the PMI-SP exam, which typically comprise a significant portion of the test.