Activity Sequencing and Dependencies in CPM

In Critical Path Method (CPM), activity sequencing and dependencies are fundamental concepts that determine the logical order in which project tasks are performed. Proper sequencing ensures that tasks are arranged in a logical flow, reflecting the real-world constraints and interrelationships between activities. Dependencies, also known as logical relationships, define how activities are connected and how one activity's timing affects another's. There are four primary types of dependencies: 1. **Finish-to-Start (FS)**: The most common type, where a successor activity cannot start until the predecessor has finished. 2. **Start-to-Start (SS)**: The successor activity cannot start until the predecessor activity starts. 3. **Finish-to-Finish (FF)**: The successor activity cannot finish until the predecessor activity finishes. 4. **Start-to-Finish (SF)**: The successor activity cannot finish until the predecessor activity starts. By accurately identifying these dependencies, project managers can develop a realistic project schedule that accounts for the necessary order of operations. Misidentifying dependencies can lead to scheduling conflicts, resource overallocations, and project delays. Activity sequencing involves mapping out these dependencies in a network diagram, which visually represents the project's activities and their relationships. This diagram serves as a critical tool for performing the forward and backward passes in CPM to calculate early and late start and finish dates, ultimately identifying the critical path. Understanding activity sequencing and dependencies allows project managers to: - **Optimize Project Schedules**: By identifying the most efficient sequence of activities, potential delays can be minimized. - **Identify Critical Activities**: Knowing which activities are critical helps in focusing resources and monitoring progress. - **Enhance Communication**: A clear activity sequence provides stakeholders with a transparent view of the project plan. - **Facilitate Risk Management**: Recognizing dependencies helps in identifying potential risks associated with schedule delays. In summary, activity sequencing and dependencies are essential for creating an accurate and effective project schedule using CPM. They ensure that all necessary task relationships are considered, which is crucial for the successful planning and execution of a project.