Gantt Charts, predecessors or critical path are common concepts in the day-to-day of a project manager. As a ‘hard skill’, scheduling is at the heart of project management, to the point where organisations even have dedicated schedulers in their projects. Yet, for many, the idea of building a timeline can look daunting.

This article will provide you with guidance on creating a well-structured and realistic project schedule, including tips for estimating project timelines, managing dependencies, and handling unexpected changes. Ready to make a start?

Don’t fail to plan or you will be planning to fail

Build your Work Breakdown Structure (WBS):

By defining project activities and breaking your project down into stages. Repeatedly ask the question “Why do we need to do to do this?” This will dissemble your project down to its constituent tasks, ensuring that you have smaller tasks that are manageable and measurable.

Sequence activities:

This is where ‘predecessors’ (aka dependencies) come to play; determine the logical order in which the activities need to be performed – are there any tasks that must be completed before others can start? Will they start right away or include a lag time?

Estimate task durations:

Estimating the time and effort required to complete each task is an art on its own. Rather than starting from scratch, consider consulting historical data or subject matter experts to develop realistic and reliable estimates. Be mindful of any external dependencies or risks that can impact on the estimate put forward.

Identify milestones:

Milestones represent events or checkpoints that mark important progress points, such as the ‘go-live’ date, the sign-off of a key governance document or the completion and approval of a project stage gate. These are the ones that your project board will ask you about, thus, they should be clearly visible in the schedule.

Add any constraints and/or deadlines:

While milestones represent an output/result of the work, constraints and deadlines refer to inputs/impact to tasks. A common example is when you are waiting for a delivery from a supplier or when there is a compliance-related deadline to be met.

Allocate resources:

Identify who do you need in the project team and allocate resources to tasks; these can be people, equipment, materials. Start by assigning a generic role and, once the resource manager reviews the request and confirms availability, replace it with a named resource to ensure proper ownership of the tasks.

Develop a timeline:

Avoid entering dates as a matter of course, dates should be an output from, not an input to the schedule – otherwise, you may as well just use a static tool as Excel. By defining the project start date and providing estimated durations and dependencies, these will shape the network of tasks and their sequence which can be represented visually in a Gantt Chart format or as a timeline.

Identify the critical path:

The critical path represents the longest duration of the project, since it is formed by tasks without any slack, meaning, if any of these tasks is late, based on their earliest start and finish dates, then, the project end date is jeopardised. Knowing which tasks are critical can give you a powerful start since you’ll then know where you’ll need to focus your attention, by crashing resources or simply by trying to accelerate progress on these tasks.

Review and optimise the schedule:

Overall, is this schedule as effective and feasible as it could be? This is your opportunity to make adjustments, balance the workload of resources, and confirm that any mandated deadlines are achievable.

Baseline the schedule:

In order to assess if the project is on track or not, you’ll need a reference point – that’s your baseline. The baseline represents a commitment to the sponsor/customer that what you are presenting in the schedule is a realistic proposition against performance will be evaluated. Well done, you now have a schedule!

Hints and Tips

Scheduling is as much of a science as it is an art! Here’s some of our lessons gathered over the years that can help you:

  • Be flexible: as the saying goes, problems happen (let us be polite). It’s therefore fundamental to include some contingency time in the schedule to account for unexpected delays and risks that materialise. Do not get rid of ‘contingency time’ – trust me, you’ll end up needing it.
  • Engage your team in the planning process: they may alert you to risks you are oblivious to or solutions you would never have thought of. Involving the team also allows them to identify dependencies and how team members are dependent upon each other. It can also foster a sense of engagement, common purpose and valued recognition.
  • Communicate the schedule: to ensure that everyone understands the timeline, work involved, and who is doing what, the schedule should be shared with all key stakeholders and beyond the project team. This will help in managing expectations and clarifying accountability.
  • Monitor and update: the schedule is a living artefact of the project; you should update progress on a regular basis and, if required, take corrective action to get back on track sooner rather than later.
  • Use a scheduling solution: scheduling tools, such as Microsoft Project for the web or, its big brother Microsoft Project, can make your life easier by automatically calculating the critical path, distribute work over the duration of tasks, level the resource workload, or produce a digestible and user-friendly timeline.


Remember, creating an effective project schedule requires collaboration, careful planning, and ongoing monitoring. It’s essential to involve key stakeholders and adapt the schedule as the project progresses to maintain a realistic and achievable timeline.

The project schedule is an indicative guide rather than a definitive timetable. Producing a precise and 100% accurate project schedule is nigh on impossible as not everything always goes to plan, and we cannot always anticipate every possible eventuality that might arise in the prosecution of a project. However, you should strive to build a realistic and workable project schedule to act as your reference point, bearing in mind that the exercise of planning is more important than the plan itself.

After all, ‘there are no good project manager, just lucky one: the more you plan, the luckier you get’!

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By: Marisa Silva (The Lucky PM)

Marisa Silva (The Lucky PM)
PPM specialist with extensive experience in industry with a focus on collaboration, PMO conception & strategy, method and capability development. Marisa also retains depth expertise in Microsoft PPM having led a large number of client deployments.

Published: 23 May 2023

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