A few years ago, I worked with a Project Manager (PM) who was seen by many as a micromanager. During our weekly schedule tracking meetings, she would go around the room and ask each team member to give progress updates. While a quick recap may have been sufficient for some project managers, this PM was eager for details and peppered team members with questions, no detail too small: How long did each task take? Did we run into any snags along the way, and How were they handled? What was our process? What resources did we use?
At the time, many of us considered her questions to be overbearing and a waste of time. In retrospect, it’s clear to see that her ability to consistently deliver successful projects on time had a lot to do with her penchant for details and persistent monitoring of the project schedule. Among the many responsibilities project managers have, project scheduling is inarguably one of the top priorities. Creating a project schedule requires some time investment upfront, but the effort pays in dividends throughout the life of the project.
Why is a Project Schedule Important?
Though some project managers may argue that a schedule isn’t necessary if you have a robust project plan, project scheduling plays an essential role in ensuring your project is a success. A good project schedule gives a comprehensive breakdown of the following:
- Timelines, including start dates and end dates of all milestones
- Tasks required to complete project deliverables
- Team members assigned to/responsible for each task
- Task dependencies
- Costs and resources required for each task
When done correctly, the project schedule provides a clear picture of the elements required to ensure your project runs smoothly. A 2019 study published in the International Journal of Engineering and Advanced Technology found that schedule management leads to optimal resource usage, enhanced employee productivity and effectiveness, and timely project completion.
Proven Project Scheduling Methodologies
There are various project scheduling approaches. The method you use will depend on the size and type of the project, stakeholder requirements, and personal preferences. No matter the technique you choose, every project should begin with a Work Breakdown Structure (WBS). The WBS provides a breakdown of every project deliverable. From there, you can add tasks, as well as the associated costs and estimated time for each task.
Once you have your WBS, consider one of the following top project scheduling techniques.
The Critical Path Method (CPM) is one of the most powerful techniques for planning, analyzing, and scheduling large-scale projects. The CPM involves identifying the sequence of tasks required for project completion. The goal here is to determine the duration of the project and identify potential flexibilities. A critical path describes the longest sequence of tasks that must be finished in order to complete the project. The CPM also estimates the minimum and maximum time it may take to complete individual tasks and the project as a whole.
- Provides clarity on task dependencies. This includes who is responsible for each task and what needs to be done in order for the next milestone to be reached.
- Calculating float and resource management. CPM helps identify tasks that can be delayed without impacting other tasks or project completion. This also gives you a good idea of how and where to use resources making it an excellent resource management tool.
- Improves future planning. CPM can be used for comparing expectations with reality. This can help inform planning and scheduling for future projects.
- Strong communication. Input from all key team members and stakeholders, not only helps ensure everyone contributes from the start, but also gives a more realistic picture of the required resources and estimated timing.
- Increased complexity. Dividing tasks into simpler steps can lead to an excessively complex critical path diagram. While the level of detail is easy enough to view on a computer, it may be challenging to print for off-site meetings with stakeholders.
- Lack of resource allocation. Critical path assumes that the resources and team members required for completing tasks are available when you need them. Other tools are required to identify potential resource constraints.
- Higher potential for delays. CPM focuses on critical path tasks, which makes it easier to overlook high-float or non-critical tasks. While your schedule should have some float, too many forgotten non-critical tasks may delay the entire project.
The Gantt chart is a tried-and-true project schedule management method that provides a visual bar chart to represent how long project tasks will take and how long the project as a whole will take to complete. Gantt charts provide an overview of tasks, show who is assigned to each task, and illuminate task time estimation and deadlines. The visual helps team members understand how different tasks depend on each other, encouraging cooperation and efficiency to get the tasks and projects done on time.
- Better efficiency and resource management. A Gantt chart provides a clear layout of dependencies, which can be helpful in encouraging team members to manage their time and resources efficiently. It also helps project managers set realistic timelines and allocate resources. Some project managers prefer the Gantt chart because it can help identify potential resource problems in time to plan for them.
- Boosts collaboration and productivity. The high-level visual of a Gantt chart helps teams understand who and what is depending on them, which helps them to stay focused on the tasks they must complete. It also encourages a “we’re in this together” work culture, as all team members can see, not only their own responsibilities but the responsibilities of coworkers and how each person and task is essential to the project.
- Makes complex information manageable. For large projects, team members may easily become overwhelmed at the amount of work they are facing to reach the end goal. A Gantt chart clearly breaks down and displays each task and the steps required to complete the task. Many people find this breakdown helpful in prioritizing their work, as they can more easily meet the next milestone.
- Helps set realistic deadlines. The clarity of a Gantt chart’s layout helps project managers see the resources required for each task, providing the opportunity to set realistic deadlines for each task, each milestone, and the project as a whole.
- Can become complex. Large projects with many tasks and subtasks can quickly make the Gantt chart complex. If your chart turns into pages and pages of tasks, you lose one of the biggest benefits to this scheduling method—the ability to see your project tasks and schedule at a glance.
- Does not show the amount of work required for each task. Taskbars in a Gantt chart do not indicate the specific resources that a task requires. This may be a little misleading at a glance, as tasks with short bars (indicating a short deadline) may require a significant number of resources. On the other hand, tasks with long bars will require minimal resources.
- May be challenging to maintain. Because tasks are connected in the Gantt chart, adding more tasks or making changes to the schedule affects the entire chart. This can be time-consuming for the project manager and confusing for team members.
The Program Evaluation and Review Technique (PERT) is a scheduling method used to visualize the steps and achievements required to complete a project. A PERT diagram is essentially a project roadmap that shows the project timeline broken down into individual tasks with their dependencies.
Since there are so many unknowns when creating a project schedule, PERT can be especially helpful in estimating the time it takes to complete each task. To use PERT scheduling, the project manager defines tasks and milestones and arranges them in order from start to finish. From there, different estimated timelines for each task can be calculated:
- Optimistic (O): the minimal amount of time it might take to complete a task
- Most likely (M): the time each task will most likely take
- Pessimistic (P): the maximum amount of time each task could take
The final project time estimate is determined by creating a weighted average of the three timelines, using this formula: (O+4M+P)/6. Many project managers like PERT, because it accounts for all possible timelines and outcomes.
- Easy what-if analysis. A PERT chart shows you all potential scenarios for completing the project and helps identify possibilities and uncertainties related to all tasks. PERT’s emphasis on the critical and subcritical paths helps to identify tasks with higher risks and may require careful monitoring to avoid delays and resource wasting.
- Encourages collaboration and coordination. PERT analysis requires information from all team members and departments, making this method a collaborative effort from the start. Once established, PERT encourages ownership of each person’s responsibilities. This motivates team members to complete their tasks on time and prevents the holding up of colleagues and the project.
- Thorough activity analysis. By viewing PERT tasks and milestones independently and in combination, you have information about the likely completion of project milestones, as well as the project as a whole.
- Manage stakeholder expectations. PERT provides three potential project timelines and setbacks, which can easily be shared with stakeholders. This transparency helps set realistic stakeholder expectations and provides a starting point for a revised timeline, should any delays come up.
- Heavy emphasis on time. PERT emphasizes timelines but is not particularly helpful at managing resources. For projects that require a significant amount of resource sharing, a PERT chart may not be sufficient for managing and tracking resources.
- Labor-intensive. A PERT chart requires a lot of time and thought to create. For large projects that require input from multiple participants, charts may be particularly complex. If you need to edit or add something to the chart, expect a significant time investment.
- Potential for data inaccuracies. The PERT chart requires accurate and consistent data, in order to establish time estimations and deadlines. If team members are new to a particular activity or aren’t familiar with a specific process, time estimates for tasks may be inaccurate. Even if your team members are experienced, you can’t control external factors that may cause delays (e.g., late delivery of supplies), which may require time-consuming chart modifications.
There are no “one method suits all” when it comes to project scheduling approaches. Each method has its advantages and disadvantages, depending on the specific project scope. It may be helpful for project managers to develop proficiency in a few different scheduling methods. That way, you’ll have the ability to use a combination of scheduling approaches or find the one that best suits the needs of your current project.