As the old saying goes, a successful project comes down to getting three things right: cost, quality and time. Do that and you’re golden! Obviously, getting there is a little tougher than that. According to Mavenlink, 70% of projects fail. One of the biggest reasons for these failures is projects not finishing within the expected timeframe. With this is mind, developing a realistic and logistically-sound schedule for any project is essential. If you’re taking on a new project or will be soon, you might be wondering “what are the basics of project scheduling?” to avoid delays. In this article, we’ll walk through the essential steps needed to draft a project schedule. Let’s dive in.
Important Project Management Scheduling Terms
Before we walk through the basics of project scheduling, we must define a few terms. Here are a few key terms and definitions related to project scheduling:
- Duration: How Long A Task Or Project Will Take.
- Critical Path: The Sequence Of Tasks, And Their Durations, That Must Happen To Get The Project Done.
- Milestones: The Date Of Which A Goal Or Specific Outcome Is Reached.
- Lead Time: How Long An Item Or Deliverable Will Take To Get.
- Predecessor: A Task That Must Be Completed Before Another Can Begin.
- Successor: A Task That Must Come After Another Task Is Complete.
A Scheduling Metaphor…
A schedule can seem daunting when just starting out. Basically, we must walk away with a sequenced, accurate summary of how the project will happen on paper – step-by-step. When we set out to do this, though, we have nothing but raw data. Going from point A to point Z is a marathon.
I’m a big fan of metaphors and visual representations to get a point across. Here’s one that helps me….
When putting together a schedule, think like you’re sculpting a statue from a big block of stone.
At the beginning, we aren’t worried about sculpting out the nose on the statue’s face – we’re just trying to get some rough parameters established to begin forming the statue’s body. We first must chip away excess stone in areas it’s clearly not needed, then worry about getting the details right.
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The finer details come later – the large but less refined steps come first.
Basics Of Project Scheduling: Create A Schedule Using CPM
In this example, we will explore the steps needed to draft a project schedule using the CPM, which stands for Critical Path Method.
When drafting a schedule for a project, it’s important to follow specific steps in order to take all of the information into consideration. Below are the steps necessary to draft a project schedule using the CPM, in the same sequence we’d sculpt the statue above – biggest to smallest. Click to jump to a specific section:
- Identify Fixed Variables & Restrictions
- Make Note Of & Quantify Long Lead Items
- Identify The Order Of Events aka ‘Sequence’
- Once A Sequence Is Established, Tasks Must Be Prioritized Using Predecessors & Successors
- After Prioritizing Tasks, Identify The Tasks On The ‘Critical Path’
- Calculate The Duration Of The Critical Path Items
- Identify Milestones In The Schedule
- Factor In Possible Overlap On The Project Schedule
- Fit In The Non-Critical Path Items
- Basics Of Project Scheduling: Additional Tips
We’ll get into the steps below using the construction of a house to create a sample project schedule. Scroll for more!
1. Identify Fixed Variables & Restrictions
Necessary completion dates, weather restrictions, testing requirements, limited resources & other limiting factors will dictate the parameters for which the schedule must fit within.
Below is a table of some fixed variables and restrictions for our house construction example:
| Signed Auth. For Contractor To Proceed | |
| Officially Break Ground | |
| Concrete Foundation Reaching Full Stren. | |
| House Is Air- & Water-Tight | |
| Move-In Ready |
These are key dates that the schedule must accommodate. Now that we’ve identified the project’s fixed dates and restrictions, we can move onto step 2.
2. Identify & Quantify Long Lead Items
Certain tasks will have a Long Lead Time associated with them. This is the time it takes to order & receive a physical item, or the time it takes to complete a process or service. Certain building materials take a long time to get in-hand, as does a complex design from a professional.
Here are just a few long lead items in our hypothetical home construction example:
3. Identify The Order Of Events aka ‘Sequence’ Using A Flowchart
Which tasks must be finished before others can begin? A simple example is building a house – the roof can’t be built before the walls! The walls can’t be built before there’s a foundation. Items must come together in a certain sequence, regardless of time.
Here is a sample project schedule flow chart used to develop a sequence of events:
4. Prioritize Tasks Using Predecessors & Successors
As said above, certain tasks cannot begin until others end. The task that must happen BEFORE another is called a Predecessor, whereas a task that must happen AFTER another is called a Successor.
Below is a table of tasks from our house construction example, along with their various predecessors and successors:
5. Identify The Tasks On The ‘Critical Path’
The Critical Path contains the key project steps that must happen in a particular order. Other non-critical items can be adjusted accordingly; they can happen independent of these critical path steps. The critical path items and the time they take are the backbone of a project schedule. The project’s time from beginning to end is almost always the time between the first critical path item starting, and the final critical path task ending.
In our house construction example, we’ve highlighted the steps we’ve decided to call the critical path items:
6. Calculate The Duration Of The Critical Path Items
A key factor in scheduling is obviously time. A project’s duration – the time it takes – is almost always the duration of the critical path. Assigning a duration to each critical path item after considering all restrictions & fixed variables is the most crucial step to calculating a project’s completion time.
Here is a basic example of critical path items in our house schedule , which totals to the approximate total project duration. These are for example purposes only!
| Design & Filings | |
| Permit Approval | |
| Excavation / Foundation | |
| Ext. Framing, Roofing & Waterproofing | |
| Sheetrock & Prep | |
| Utilities – Plumbing, Elec., Etc. | |
| Kitchen, Bathrooms, Sinks, Appliances | |
| Final Inspections & Sign-Offs | |
| TOTAL |
7. Identify Milestones In The Schedule
Milestones are dates when a specific goal or outcome has been reached. A milestone can be the completion of a task on the critical path, or a date involved with a specific restriction or fixed variable (step 1). By making sure that each milestone is reached, a project manager is keeping the entire project on track.
As we mentioned earlier, milestones can be reaching fixed dates or specific critical goals. In our house example, this includes having the plans approved/permitted, pouring the foundation, having the house framed, getting the interior air/water-tight, utilities completed/signed off, etc.
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8. Factor In Possible Overlap On The Project Schedule
Sometimes, the timeline of critical path tasks can be consolidated to shrink the overall schedule duration. This is often done by breaking these tasks into smaller tasks and figuring out which of them could start while the main task’s predecessor is still going.
9. Fit In The Non-Critical Path Items
The less critical items can now be scheduled around the critical ones. If a task can happen within a range of dates but takes a lot less time than given, this task has float associated with it. If a one month window of time is available for a task that takes one week, then the task has a few weeks of float to play with.
Basics Of Project Scheduling: Some Additional Tips
Thanks for reading this far! We’ve now reviewed the process of drafting a project schedule and all of the steps that go with it.
Here are a few additional tips to consider when drafting your next schedule:
- Request lead times and estimated timeframes from any consultants and contractors when first requesting a price.
- Similarly, make clear any fixed variables and deliverable dates when requesting a price.
- Always add a contingency to each task’s expected duration.
- Factor in revisions and typical delays while creating the initial schedule.
- Specifically identify milestones on the critical path, along with all of the predecessors for each phase. This makes clear what is most important to achieve during the vital phases of the project
The Basics Of Project Scheduling In Summary
This article has covered all of the basic knowledge needed to begin creating project schedules. If you came here wondering “What Are The Basics Of Project Scheduling?“, you now have a solid understanding of project scheduling terminology and the 9 key steps to follow when creating a CPM-based project schedule! Thanks again for reading!
