Critical Path Method (CPM)

Definitions

PERT: Project Evaluation Review Technique

Critical Path Method (CPM): Known as a Network Diagram; charting style with different paths and events in a diagram to show duration and task order.

Interface Events: When different portions of the projects are planned, per different scope of work or other reason, this would sometimes require different Network Diagrams. When the Network Diagrams have events that coincide with each other, these events are interface events and are named as such since they allow the two diagrams to connect/interface.

Float Path: All other paths besides the Critical Path are considered float paths. These are considered ‘Float Paths’ because they have built in ‘float’ to their time schedule.

Milestone Events: Important points in the construction process. These typically occur at a specific date. For example, issuing permits on December 1st. These are considered ‘checkpoints’ in the project.

Float: Amount of time in a task that that the task can be delayed without causing a delay in the subsequent task or project completion date.

• When the project is completely void of calendar date restrictions, critical tasks will have zero float in them, since a delay in these would cause a delay in the project schedule.

Introduction

A Critical Path Method Chart defines activities with a starting and stopping point as well as sequence of the activities and duration of those activities and how they interface together.