Critical Path Analysis and Adjustment

Critical Path Analysis and Adjustment: A Comprehensive Guide

Why Critical Path Analysis and Adjustment Is Important

Critical Path Analysis and Adjustment is a cornerstone methodology in schedule management that allows project managers to:

• Identify the sequence of activities that determine the overall project duration
• Focus resources on activities that directly impact the completion date
• Make informed decisions when compressing or adjusting the schedule
• Communicate priority tasks to stakeholders
• Proactively manage schedule risks

What Is Critical Path Analysis?

Critical Path Analysis is a technique that identifies the longest path through a project network diagram, representing the shortest possible project duration. The critical path consists of activities with zero float (slack), meaning any delay in these activities will delay the entire project.

Key components include:

• Critical Path: The sequence of activities that determines the earliest completion date
• Float/Slack: The amount of time an activity can be delayed before affecting the project end date
• Near-Critical Paths: Paths with minimal float that could become critical with slight delays

How Critical Path Analysis Works

1. Create a Network Diagram: Illustrate activities and their dependencies

2. Forward Pass Analysis: Calculate the Early Start (ES) and Early Finish (EF) dates for each activity, moving from project start to finish

3. Backward Pass Analysis: Calculate the Late Start (LS) and Late Finish (LF) dates, moving from project finish to start

4. Calculate Float: Determine float (LS - ES or LF - EF) for each activity

5. Identify the Critical Path: Activities with zero float form the critical path

Critical Path Adjustment Techniques

When the schedule needs optimization, project managers can apply several adjustment methods:

• Fast Tracking: Performing activities in parallel that would normally be done sequentially

• Crashing: Adding resources to critical activities to reduce duration, based on cost-benefit analysis

• Resource Leveling: Adjusting start and finish dates to address resource constraints, which may change the critical path

• Activity Splitting: Breaking activities into segments that can be completed with interruptions

• Scope Reduction: Modifying deliverables to reduce work on critical path items

Exam Tips: Answering Questions on Critical Path Analysis and Adjustment

1. Understand Float Calculations:
• Total Float = LS - ES or LF - EF
• Free Float = ES of successor - EF of activity
• Pay attention to how changes in duration affect float values

2. Critical Path Identification:
• Remember that multiple critical paths can exist
• Activities with zero float are always on the critical path
• The critical path may change during project execution

3. Schedule Compression Questions:
• Know the difference between crashing (adding resources at additional cost) and fast tracking (increasing risk)
• Calculate crash cost per time unit = (crash cost - normal cost)/(normal time - crash time)
• Apply compression to critical path activities first

4. Network Diagram Analysis:
• Practice forward and backward pass calculations
• Be prepared to recalculate when activity durations change
• Identify how changes in one path can create a new critical path

5. Common Exam Scenarios:
• Calculating the impact of delays on project completion
• Determining which activities to crash to meet a deadline
• Analyzing the effects of resource constraints on the critical path
• Evaluating trade-offs between time, cost, and risk

6. Remember Key Formulas:
• Project Duration = Length of Critical Path
• Activity Duration = EF - ES = LF - LS
• Total Float = LS - ES = LF - EF

By mastering Critical Path Analysis and Adjustment, you'll be equipped to make strategic decisions that optimize project schedules while balancing constraints of time, resources, and cost.