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Six Critical Path Best Practices

Critical Path Method

It’s the start of your project, and you have hundreds of tasks that need to be performed by dozens of team members in order to get the finish line. At the onset of any project, the job of prioritizing tasks, identifying the most important ones, and assigning resources and responsibilities can feel daunting. That’s where the Critical Path Method (CPM) comes in. Developed in the 1950’s, the CPM remains an essential part of planning any project.

So what is the Critical Path Method?

The critical path is the distance between the start and the finish of your project. Essentially, it is a way of saying, “How long does each required task take before we finish?” The critical path includes project phases and the length of time for each phase, as well as project tasks and their duration. Critical Path Method allows you to calculate the “critical path” of a project by showing the necessary order of tasks, the ideal project schedule, and any potential problems with resources and scheduling. CPM highlights the crucial stages where delays can hinder the project and also indicates where extra resources can accelerate it.

Critical Path Method Steps

Determining your project’s critical path involves six steps:

  1. List all the tasks required to complete the project. Try to use a hierarchical breakdown of the project, noting every deliverable.
    • “Critical” tasks are tasks with deadlines that directly impact the project timeline.
    • “Float” tasks are those that can be delayed without extending the project. They most likely run parallel to the critical path.
  2. Note the duration of each task. Determine how long each task will take to complete before moving on to the next one.
  3. Identify task dependencies. A task dependency is when one task cannot start until another has been completed.
  4. Identify your project milestones. These are the project’s major phases.
  5. Create a list of your project deliverables.
  6. Assign resources to your project tasks. Resources include people, equipment, facilities, funding, and anything else required for the completion of your project.

Once you have laid out all of this information, you can use the CPM to calculate the longest sequence of planned activities from the start to finish, hitting all significant milestones in between.

Critical Path Method Best Practices

As project managers, we are all likely familiar with this process, but what the best practices to follow when implementing CPM? Follow the six recommendations below and you’ll be well on your way to a successful project in no time.

Get familiar with Microsoft Project

Developing a project’s critical path within MS Project streamlines the process. The software helps you clearly lay out the project’s phases and tasks and automatically forecasts the project’s end date. Visit MPUG’s Critical Path 101 for an introduction on how to get started.

Prepare for the “what-if” scenarios

Every experienced project manager knows that things don’t always go exactly as planned. That’s why it’s important to make room for the “what-ifs” that may occur when mapping out your critical path. Once you know more about your project’s schedule, you can experiment a bit to see what effect any delays or setbacks will have on your project’s timeline. You can do this in Microsoft Project by:

  1. Extending a critical task by increasing its duration. This will show you all the other critical tasks that would be impacted by this change, show you any non-critical tasks that gain extra time, and reveal the total slack.
  2. Extending a task that possesses free slack. Slack is the amount of time a task can be delayed without any delay in the successor activity or the project finish date. Free slack is the time a task can be delayed without delaying its successor task. Extending a task with free slack will show you that no other tasks are affected until you exceed the free slack available.
  3. Extending a task that only possesses total slack. This will demonstrate how other tasks will be rescheduled. Total slack is the time a task can be delayed without delaying the project finish date.

Stay Flexible

Along with preparing for the “what-if” scenarios of your project, staying flexible is equally important. Any change or delay will directly impact your project timeline, requiring a revision to the plan. Keep in mind that critical paths can change throughout the life of the project, depending on delays, resource availability, and any other unforeseeable issues that pop up.

The good news is that because you’ve measured each task’s duration in your critical path planning, you can reasonably estimate a new timeline with some accuracy when something comes up that requires a delay. This will keep your stakeholders and project sponsors happy. Yes, the transparency a critical path provides is unparalleled, and it allows the entire team to see the big picture and the small details of the project.

Check that your critical path makes sense

This may seem like an obvious point, but it’s important to ensure that your schedule works for you, your stakeholders, and the team members who will be executing the tasks. Once it’s been developed, it’s important to share the project’s critical path and timeline with everyone involved.

Having an easily accessible critical path keep everyone “in-the-know” throughout the life of your project, and ensures all stakeholders and team members are aware of deadlines as well as delays. It can also be helpful to team members who wouldn’t otherwise see the “big picture” of the project, providing them with a deeper understanding of where their duties fit into the larger scope of the project.

Use the critical path to support your team

Once you’ve created a critical path to keep the project on track and keep your team in the loop on all elements of the project, you may wonder, Now what? As the PM, it’s your job to manage the deadlines and communicate often with your team. See the critical path as more than just a to-do list, but rather a continuing team effort where each member depends on each other for support, and, eventually, the project’s success.

When creating your critical path, make sure that all tasks included have specific deadlines and that the tasks have been delegated to the right person. Missed deadlines can sometimes be avoided by paying attention to your team and understanding their workload, which MS Project will help you see.

Create project status reports to update stakeholders

A project status report (or milestone report) is essentially a snapshot of where things are at with your project. This will come in handy not just for yourself to see how all elements of the project are going, but also so that you can share project updates with your stakeholders.

You can create custom project status reports using data within your critical path in MS Project. MS Project allows you to create and customize graphical reports of any of the project data you want to share. MS Project can also help you create a status report that includes three important elements:

  1. Overall Picture showing the overall health of your project.
  2. Milestones reveal which milestones are complete, which ones are in progress, and which ones are coming up next.
  3. Issues or the obstacles arising in the project.

Do you have more tips and tricks to add for project managers using the Critical Path Method?

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Written by Lindsay Curtis

Lindsay Curtis writes about communications, education, healthcare research, and parenting. She has extensive experience as a Project Manager, primarily in the healthcare and higher education sectors. A writer by day and a reader by night, she currently works as a Communications Officer for the University of Toronto. She also provides freelance copywriting and social media strategy services for businesses of all sizes. Learn more about Lindsay at www.curtiscommunications.org.

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  1. These are all great point but I would suggest that using monte carlo simulation to help predict potential changes to the critical path and provide more realistic insight into future dates should be included under ‘stay flexible’. It’s better to be prepared rather than just really good at reacting.

  2. I agree with John’s point, and add that creating a Risk Adjusted Gantt chart through Full Monte (Schedule Risk Assessment) is the best way to see predict potential changes.

  3. Deliverable vs task is a pet peeve of mine, but a different discussion.
    The critical path is the longest, contiguous distance between the start and the finish of your project. In a classic waterfall project, it should have at least one deliverable from each phase REQ, DES, DEV, QA, IMP.
    Critical Path determines the finish date. In theory, crashing the schedule is the only way to bring a slipped critical path back to baseline and deliver the original scope.
    I closely monitor all deliverables that are within 5% of critical path based on remaining duration. The monitoring criteria are on time start, %complete (earned schedule), and resource units. If the resource units go above 120% I become concerned the task has actually slipped but a revised finish date has not yet been communicated.

  4. What is the difference between critical path and critical chain? Can we find out critical chain from MSP?


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