Critical Path Method (CPM)

The critical path method, or critical path analysis, is a project management tool used to assist in scheduling long-term projects. The method was developed in the late 1980s and has been used in a variety of project types including software development, research projects, project development, engineering, plant maintenance, and many more. In manufacturing and related industries, the critical path method can be used to maximize efficiency.

Planning a project always includes a start point and an ending point, and the project itself is carried out between these points. The critical path method is an algorithm that shows the path of tasks and activities to complete the project, usually diverging and coming back together at different points. The goal the best path for the project in order to effectively schedule and plan for the project.

Before constructing a model for CPM, the following information should be gathered:

  • A list of all activities that are essential to the completion of the project.
  • The time it takes for each activity to be completed.
  • Dependencies between the activities.
  • An end point – typically a milestone.

It is important for those planning the project to differentiate between essential and non-essential activities. Essential tasks are referred to as critical activities are tasks that must be done before the end of the project. For example, if a project is to open a new facility, essential tasks would include building the physical structure, running electricity, and passing safety inspections. Any activities that can be done after the deadlines or tasks that involve adding optional or custom features can are left off the critical path and should be de-prioritized.

Utilizing the critical path method is done through creating a diagram that clearly shows the longest path of planned activities to achieve the end goal of the project. The visual component of CPM will help managers decide when to schedule the activities to avoid wasted time as well as determining the earliest and latest each activity can begin and end without making the project task list longer. Manufacturers use this technique to identify delaying factors and implement solutions, effectively reducing their lead time.

Managers will need to evaluate whether or not the CPM will be the right fit for the project at hand. The critical path method is great for projects that span over weeks or months but is also beneficial for projects that involve many teams of people.


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