Critical Path Method (CPM)

Critical Path Method (CPM) is a mathematical algorithm used for project scheduling that analyzes and represents the project network to identify the longest path through the network diagram, determining the shortest possible project duration. The critical path consists of activities that must be completed on time to ensure the entire project stays on schedule. In CPM, activities are represented as nodes or arrows in a network diagram with dependencies shown as connections between them. The process involves five key steps: 1) Activity identification and sequencing, 2) Network diagram construction, 3) Time estimation for each activity, 4) Forward and backward pass calculations, and 5) Float determination. During the forward pass, the Early Start (ES) and Early Finish (EF) times are calculated. The backward pass determines Late Start (LS) and Late Finish (LF) times. Total float is calculated as the difference between LS and ES (or LF and EF). Activities with zero total float form the critical path. These activities have no scheduling flexibility—any delay in a critical activity directly delays the project completion date. The critical path may change during project execution as activities are completed earlier or later than planned. CPM helps project managers focus attention on critical activities, allocate resources effectively, evaluate schedule compression options (fast tracking or crashing), and assess schedule impacts of changes or delays. CPM differs from PERT (Program Evaluation and Review Technique) in that CPM uses single point time estimates while PERT uses three-point estimates to account for uncertainty. Understanding CPM is essential for schedule management, resource optimization, and communicating timelines to stakeholders in a clear, structured manner.

Critical Path Method (CPM) is a mathematical algorithm used for project scheduling that analyzes and represents the project network to identify the longest path through the network diagram, determini…

Concepts covered: Schedule Network Diagram Construction, Float Calculation, Total Float and Free Float, Resource Leveling and Its Impact on the Critical Path, Forward and Backward Pass, Schedule Compression Techniques: Crashing and Fast-Tracking, Leads and Lags in Critical Path Method, Dependency Determination and Types in CPM, Lead and Lag Times and Their Effect on the Critical Path, Schedule Risk Analysis and Contingency Planning in CPM, Leads and Lags in Project Scheduling, PERT Analysis within CPM, Forward Pass and Backward Pass Calculations, Critical Path Identification, Working Calendars and Their Impact on CPM Scheduling, Dependency Determination and Types in CPM Scheduling, Critical Path, Activity Sequencing and Dependencies in CPM