Critical Path Method and PERT Charts

PERT stands for Program Evaluation Review Technique, and it’s surprisingly easy to master than it may initially appear. Use this guide to better understand the critical path method (CPM) and how to use it in conjunction with review techniques offered in PERT charts.

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What is the critical path method (CPM)?

The critical path method, also known as CPM, can be a helpful tool to use to better schedule and manage complex projects and the amount of time individual tasks may require. The CPM designates the specific order and sequence of actions that inevitably determines the duration of the project you’re scoping out. This is especially useful in managing projects with areas of overlap, long time-consumption, or even delay because you can approach the scheduling of a project on a separate task basis, visualize them in a flowchart, and then get a near exact estimate on the duration each individual task will require. In many cases, project managers choose to combine PERT and CRM so they can better visualize every task, where they fall into order, and how long they are expected to take.

Benefits of the critical path method

The critical path method, or analysis, was developed in conjunction with PERT. Both techniques are used to manage projects within a specific timeframe. The critical path method calculates the longest path that is possible with your planned activities, then figures out the time constraints that each activity is under. The project manager can then examine these paths and determine the steps that should be taken to increase efficiency. Try using CPM for project management and scheduling—your organization will save time and money by adhering to its ultra-accurate estimates

  • Identify the most important as well as the longest duration tasks within a project.
  • Help reduce timelines by finding tasks with durations you can modify, but are required to stay the same to meet your set deadline.
  • Compare planned progress with actual progress.

How to use the critical path method with PERT charts

Applying the critical path method in unison with PERT charts can truly elevate the way you manage projects and give you a realistic deadline and process flow. Chart out your project in a PERT chart and in the last step, use the CRM to estimate times of completion to your tasks. When creating a PERT chart, you’re going to give rough estimates toward each task or scenario. You’ll want to estimate both the longest and shortest possible time each activity will likely take. You’ll even want to take delay into account and estimate the longest potential task durations if there are chances of any setbacks.

Once you’ve ordered your project tasks and have applied estimated time durations, make a PERT chart to include your estimated time durations.

In this example, we’ve created a PERT chart with eight tasks, each taking a different length of estimated time.

critical path method

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Once we’ve identified the different path options with their time frames from beginning to completion, we see that the most critical paths are A and G because they require the longest time duration to complete, with several other tasks being dependent on path A and therefore increasing their estimated time of completion.

From this, we now have the option to dive deeper into the process of the individual tasks and identify any potential areas to reduce time or get an exact estimate on how long it’s going to take moving forward.

Try applying the critical path method to your PERT charts when you’re planning projects and experience the realistic expectations and deadlines this approach can offer.