A project plan is at the heart of every successful project. At the heart of every project plan is project scheduling to set the timing of each activity.
In this guide, we’ll look at all the key elements of project scheduling. We will largely follow the process structure in the 6th Edition of the PMI‘s Project Management Body of Knowledge (PMBOK Guide). It’s a reliable guide. But, we’ll also step outside it’s Project Scheduling Knowledge Area (KA), to survey the full scope of the discipline.
Project scheduling is the creation of a plan for when the project will deliver its products (or deliverables). This will include how it will time and sequence all the activities that you will need to carry out and how and when you will apply resources to each task. The
At its simplest, your Project Schedule is a timetable of what you will do and when you will do it. It shows a planned start and completion date for each activity. This means estimating resource requirements and task
Necessarily, it will also show the resources that you will allocate to each activity. So, this means that it is not possible to separate the scheduling processes from those of resource management.
Likewise, it starts from the things you’ll need to produce and the tasks this will need. So, again, project scheduling is also closely associated with your Project Scoping processes.
Your Project Schedule will be a key project document that will need formal approval. But it will also need to remain under constant review. You will probably have to revise and update your project schedule during the life of your project; sometimes many times.
This is how the Glodssary section of the 6th Edition of the PMBoK defines Project Schedule:
An output of a schedule model that presents linked activities with planned dates, durations, activities, and resources.A Guide to the Project Management Body of Knowledge, 6th Edition.
© The Project Management Institute, 2017.
Sometimes, people use the terms ‘Project Plan’ and ‘Project Schedule’ interchangeably. In truth, your project schedule is one part of a larger project plan for how you will deliver your project.
And that, in turn, is governed by what the PMBoK calls a ‘Project Management Plan’. This sets out how you will manage your project:
In the PMBoK, the Project Management Plan is the output of process 4.2: Develop Project Management Plan.
The figure below illustrates the Project Scheduling process. It also includes other, related, elements that form part of project planning.
We will use this chart as our navigations aid. But, because the PMBoK is an important guide to many of our readers, who may be considering preparing for a CAPM or PMP qualification, we’ll relate our process back to the guidance within the PMBoK.
This part of the process sets the context for how you will carry out your project scheduling. In the PMBoK process (6.1), the output is a Schedule Management Plan. It forms part of the wider Project Management Plan that we described above.
There are a number of other key inputs. The PMBoK identifies them as:
I would add three other essential elements:
The essential elements of your schedule management plan will be your approaches to:
For me, the most valuable part of this process in the PMBoK is the list of additional components of the schedule management plan, in section 220.127.116.11. I’ll summarize it:
The first step in actually creating a Project Schedule is to define the activities that the project will need to carry out. For many project managers, this is the task of scoping.
However, for PMBoK users, ‘scope’ refers to the products or services the project produces: its outputs or deliverables. For project managers coming more from the UK tradition, scope refers to the scope of work; the full set of activities that you’ll need to carry out. We have a companion guide called: ‘Scope Management Plan: Everything You Need to Know’.
Consequently, the tools you will use for this will depend on your interpretation of ‘scoping’.
For some, you will start with an activity-based Work Breakdown Structure (WBS) as the primary method for producing your comprehensive list of activities. But, if you come from a US/PMBoK tradition, you will decompose your product-based WBS (PMBok process 5.4) and consider the activities you will need, to produce each of the deliverables.
PMBoK considers a milestone list as an output of this process. I think of it as more fundamental. So, we’ll consider this as a separate step, after we’ve looked at sequencing.
Sequencing the activities in your project plan is about deciding the order in which you will carry them out. There are two factors you will take into account:
These are dependencies that determine a necessary sequence of activities. You have no choice in the order of two more
These set a sequence based on what you and your project team consider to be best practice or the most advantageous way of doing things.
Here, there are more than one way to structure your sequence, but you lock in one approach for your own reasons:
There will be consequences to your choices here. So, it is essential that you document these choices and the reasoning you have applied. This may be part of your ‘Assumptions List’.
The first way to think of dependencies is to consider where they come from:
Unfortunately, we don’t have space here to go into this aspect of project scheduling in detail. But, you will need to understand the four potential types of dependencies and their relative commonness.
But what if task B needs to start after the completion of task A, but not straight away? Maybe 1 week later? That’s a ‘lag’ of one week. Or maybe it needs to start 2 days after task A starts. That’s a ‘start-to-start dependency with a 2-day lag’.
Or, maybe task B needs to start 3 days before task A finishes? That’s a ‘finish-to-start dependency with a 3-day lead’.
Milestones have two purposes in Project Scheduling (and another in Project Control).
In project scheduling, your milestones can either :
Together, these two uses create a framework within which you will make project scheduling decisions.
So, a milestone list can be one or both of:
For my money, estimating is the hardest part of this process. You’ll need to deploy a range of estimation techniques to maximize the likelihood that you have a robust
PMBoK’s ITTO (Inputs, Tools & Techniques, Outputs) for this process (6.4) provides a long list of documents that will contribute to this, but I think it more helpful to focus on the steps you will take to estimate the durations of activities.
The effort you will need for any task will depend on the:
You have a number of estimating methods you can use, but these are outside the scope of this article. So, do take a look at our article: ‘Project Estimation: Master the Art and Craft’. These include:
Now it’s time to put all of your work together into a project schedule. There are many tools for building your plan, of which the most frequently used are the various forms of Network Chart. These allow you to lay out the sequence of tasks as the dependencies specify, and add durations to each.
Common conventions for how to do this are the:
In the PMBoK, this is subsumed into process 6.5, Develop Schedule, in the form of ‘Resource
Here is where you will assign specific resources to each task. Of course, I principally mean people, but you will also allocate physical resources like assets, materials, and equipment).
Thinking about your people, you will also beed to think about:
I know that we have talked about logging assumptions for your discretionary dependencies above, but there is more to note. Project scheduling is at the heart of making sure you deliver your project on schedule. So it is a source of significant risk.
And risk arises from two things:
You will need to manage both of these throughout your project. So,
Shift happens and your project will slip against its baseline schedule. So, you will need to:
As you progress, you will learn more about your project and better understand the risks you face. So, you need the flexibility to amend your project schedule throughout your project. And, I recommend you do so in a planned way – either at key milestones or on a regular cycle (such as quarterly). This does not mean, by the way, that you are not free to review your schedule whenever the need arises.
Another important aspect of schedule control is managing change requests. If that’s of interest to you, we recommend our article, ‘OnlinePMCourses Guide to Change Control’.
It would take a whole series of articles to fully describe the tools and techniques that you can use as part of the Project Scheduling
And no, I’m not just doing to copy out all the tools and techniques from the PMBoK ITTOs. Of course, you know that expert judgment, data analysis, and meetings will be involved. You can look those up as well as I
But, I do want to point you in the direction of some of the most important tools:
To end this survey, I would like to highlight a few simple tips, from my own experience.
And some brains are better than one. By which, I mean: don’t try to do your project scheduling on your own. If you have a team, harness their wisdom. You get two major advantages doing this:
My preferred approach to all aspects of planning: scoping, scheduling, and budgeting is simple. I allocate chunks of that planning to workstream leaders and ask them to work with their teams to put together the scope, schedule, or budget.
My job is then to make sure each component meshes together without overlaps or omissions. I leave the technically demanding details to the technically adept experts on my team.
I would not, for one moment, want to suggest that the steps in this article are all mandatory discrete steps for every project. A lot of the
If you’re one of them, then for you, everything but controlling the schedule is a single process. You’ll do all of it in parallel, and probably on your own or with just one or two colleagues. That’s fine.
For example, I could make an equally strong case for swapping the sequence of some of the steps in the process above. There are numerous equally valid approaches. Because none properly represents the way we really work
What we actually do is work through the process until we get to a settled answer at one step. Then we cycle back over the previous steps to:
This constant cycling back and reviewing – or iteration – is the true nature of project definition, project planning in general, and project scheduling in particlar.
We’d love to hear from you about your ideas, experiences, and questions about project scheduling. Please do contribute to the comments below, and we’ll respond to everything you write.
Dr Mike Clayton is one of the most successful and in-demand project management trainers in the UK. He is author of 13 best-selling books, including four about project management. He is also a prolific blogger and contributor to ProjectManager.com and Project, the journal of the Association for Project Management. Between 1990 and 2002, Mike was a successful project manager, leading large project teams and delivering complex projects. In 2016, Mike launched OnlinePMCourses.
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