Critical Path Analysis

Overview

Critical Path Analysis (CPA) is a technique used for managing complex projects.
The technique allows you to plan all tasks that must be completed as part of a project, and to assess which tasks are critical — that is, if they are delayed, they will delay the whole project.

An Activity represents a task in the project that consumes time and resources. Each activity is denoted as an arc in a network diagram.
Events represent the start and finish of activities. They are shown as nodes or vertices in the network.
Dummies are activities that have no duration. They are used where necessary to maintain the logical sequence of the project.
Precedence Relationship is an ordering constraint which establishes a sequence for project activities. It dictates that one activity must be performed before another activity is started.
The Earliest Start Time (EST) is the earliest time at which an activity can start, given that its preceding activities are finished.
The Latest Finish Time (LFT) represents the latest time by which an activity should finish so that the projects meet its overall deadline.
The Float or Slack of an activity is the total time you can delay a task without delaying the project.

The Critical Path is the longest path from the start to the end of the project. It determines the total time required to complete a project.
The activities on the critical path are known as critical activities. If any critical activity is delayed, the completion time of the project will be delayed accordingly.
Activities not on the critical path have a slack time and can be delayed without changing the project completion time.

A CPA Network Diagram is used to represent the project tasks, their dependencies and activity times.
It typically starts with a single start node and ends with a single finish node.
It helps in identifying the critical path and getting a clear visual overview of the project schedules, task durations and constraints.