Fast, Cheap, Good… Pick two. Every freelancer, business owner, and car mechanic knows this phrase. If you want something done good and fast, you’re going to be paying a premium. If you want it cheap and fast… well, you get what you pay for.
Projects operate under similar limitations called the triple constraint of project management. Scope, time, and budget–any change in one of these factors will impact the rest.
However, while the triple constraint is an easy way to understand the basics of project management, it quickly falls apart in the real world.
Not only does this ‘project management triangle’ ignore many other constraints, but almost every company runs multiple projects at once, each with competing priorities and specific needs.
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Rather than battling for scarce resources, the best project managers balance both the triple constraints of their project and the competing needs of a growing company.
In this guide, we’ll show you how to find that balance, keep your eye on the bigger picture, and lead teams to creative and innovative solutions within all the typical constraints of a project.
What is the classic Triple Constraint of project management?
In project management theory, the classic triple constraint states that a project’s scope, time, and cost are connected and related. If one changes, then the others must react similarly and predictably.
Why does this matter? Because projects are all about trade-offs.
If you want to finish the project earlier (lower the ‘time’ portion of the triangle), then you’ll have to spend more money (cost) and potentially reduce your deliverables (scope).
Or, if you want to lower your budget (cost), you’ll need to push your deadlines (time) and reduce your scope.
And if you want to make more (scope creep) without pushing the deadline? Well, you’re going to spend a lot more than you think.
Picture each element of the triple constraint as points on a triangle with quality in the middle (many people also call the triple constraint the iron triangle, project triangle, or project management triangle). To ship at the quality level you want, you need to keep each element in check.
In your work, you can probably recognize all sorts of processes, workflows, and documents you use to manage the elements of the triple constraint of project management:
- Project plans and scope of work documents are used to handle scope creep and understand constraint tradeoffs
- Deadlines, estimates, and project management tools like Planio help keep you on schedule and handle project time management
- Resource planning, risk management, and even stakeholder communication are designed to help you stick to your project’s budget
Understanding the triple constraint is one of the keystone skills of every great project manager. Let’s say you have a website redesign project with a timeline of 2 months and a budget of $100,000. But then your client realizes their designer won’t finish all the illustrations and wants you to add them to the project (i.e., scope creep!)
Understanding the triple constraints, you’ll know to either push back or adapt the project’s timeline and budget to make up for the increased scope.
An example like that is a simplified version of how the ‘iron triangle’ works in practice. So before we go any further, let’s take a quick moment to dive into the specifics of each element.
Understanding the elements of the ‘project management triangle’
By its very definition, a constraint is a limitation or restriction. No matter how many resources you throw at it, every project operates within the constraints of the project management triangle.
Understanding the triple constraint is both a warning system and an idea generator.
When you clearly understand where trade-offs need to be made, you’ll be able to help your team adapt and solve for them earlier.
So let’s look at each element a bit more in-depth.
Project constraint #1: Time (i.e., schedule)
Time is the most straightforward constraint to understand. There are only so many hours in a day to work. And even with all the resources in the world, you can’t make more time. (You can, however, be more efficient with the time you have, which we’ve written about here!)
Time constraints make it impossible to do everything, which is why time management and project planning are such essential skills.
If you have a clear go-to-market date or if you have dependencies and need to hit a deadline to allow a different project to start on time, then you’ll need to pay special attention to your time constraints.
Managing time constraints comes down to a few key elements:
- Understanding how long tasks should take (i.e., estimating time)
- Creating a manageable project plan and deadline
- Monitoring progress with the right tools (like Planio!)
However, time isn’t just about scheduling and estimating. Time is also your most crucial opportunity cost. Choosing to spend your team’s time on one project means you can’t spend it on another (at least not right now).
Project constraint #2: Scope
A project’s scope is everything that needs to be completed to hit expectations.
Obviously, it’s impossible to do everything you’d like to do, which is why it’s so important to create and document shared expectations early on–for you, your team, users, and stakeholders.
Mismatched or assumed expectations can sink any relationship. If you think the project should look a certain way, but your users or stakeholders expect something different, no one will be happy.
In the same way, starting a project but then chasing ‘cool’ new features or functionality along the way is an easy way to blow past deadlines, go over budget, and burn out your team.
Setting and communicating a shared project scope early on with a scope of work document (SOW) is one way to manage your scope limitation.
While monitoring any increases to the scope and creating a straightforward change control process is another way to make sure the scope doesn’t get out of hand.
Using a tool like Planio to map out tasks and deliverables for a sprint or milestone is a great way to keep an eye on your scope and set shared expectations.
Each task or issue in Planio gives you opportunities to communicate and track changes to scope as well. You can go into detail about a task’s status, priority, assignee, category, start and finish dates, as well as estimate time and progress:
Additionally, you can add yourself and any other teammates as watchers so you can get updated on any changes or progress.
Project constraint #3: Cost (i.e., budget)
Lastly, even the most well-funded companies need to manage the resources that go into each project.
Creating a clear and shared project scope and estimating the time commitment should give you the basic elements to set a budget. However, it’s a mistake to think your cost constraint operates the same way as time and scope.
If you’re building a car, it might be safe to say that you can speed up production by spending more money (or lower costs and take your time). However, software teams have fewer ‘hard’ costs like materials and equipment. Instead, the higher the scope, the more time it will take your team to complete the work and the more you’ll spend on salaries.
All this is to say that while your budget can dictate or change the scope, it’s more closely tied to and influenced by your time constraint.
What the classic project management triangle gets wrong
On the surface, the triple constraint of project management seems to make sense. What you can achieve (scope) depends on the resources available to you (time and cost).
Yet, as any working project manager will tell you, projects rarely work out so cleanly. As Angelo Baratta explains on the Project Management Institute:
“Why is it that the majority of projects that are over budget are also late? Why is it that projects that are both late and over budget also have a tendency to under-deliver (scope)? Again, this is not consistent with the Triple Constraint.”
There are two problems with the triple constraint model.
First, as we’ve mentioned, time and cost aren’t independent constraints that can be fiddled with to find a happy middle ground.
The cost of a project is a fixed factor. The budget spent on one project is the same as any other. However, time is a relative factor. Spending a month extra on one project pushes your entire project pipeline out of whack. You can’t scale up time with the same ease as asking for more budget.
Second, the triple constraint isn’t a helpful tool for measuring the success of a project.
If you went over budget and missed your deadline, but the results boosted revenue by 50%, I think everyone would agree the project was a success. Whereas, if you work within your constraints but on the wrong project, it’s a waste.
The triple constraint shifts your focus from the business opportunities to PMVM–Project Manager Vanity Metrics. Is it impressive that you hit your deadline? Sure. But what’s more impressive is if the product you made met or exceeded your business goals.
Ultimately, the goal of any project should be to create something that delights customers, grows your business, and aligns with your product vision.
This isn’t to say that there’s no point worrying about time, budget, or scope (that is your job as a project manager, after all). But instead that there are more constraints and opportunities than the triple constraint of project management lists.
Expanding the triple constraint for the modern project manager
Thinking through the framework of limitations can help you wrangle an otherwise chaotic and overwhelming project. However, modern teams need to look past the classic triple constraint and address the complexities and nuances of running projects.
One approach from the latest version of the Project Management Body of Knowledge (PMBOK) is to add a few more typical ‘constraints’ to your list. Here are the six project constraints listed in the PMBOK:
(You can learn more about the PMBOK and discover more of the best books for project managers here!)
We’ve already covered the classic triple constraints of time, scope, and cost. So what about these new additions?
Project constraint #4: Quality
You can think of the ‘quality constraint’ as a more precise version of your scope. Rather than focusing on what was delivered, quality refers to ‘the characteristics of a deliverable.’
For example, if your project is running late and over budget, you might not have to reduce the scope (what is delivered). However, you will have to reduce the quality of those deliverables through reduced functionality, less testing, or unpolished design.
As a project manager, you can help define a threshold of quality so that teams know if there’s flexibility in what can be considered ‘done.’ Does your final functionality have to be exactly to the spec listed in the SOW? Or is 80% good enough if it means sticking to the other constraints?
Modern teams need to look past the classic triple constraint and address the complexities and nuances of running projects.
Project constraint #5: Benefits
Benefits refer to the business case for a project and the value it delivers to users.
Every project needs a clear purpose with measurable and agreed-upon metrics to determine its success. If you discover that the benefits are no longer there during or before you finish a project, you need to adapt.
Here’s an example. Let’s say you’re building a new feature that’s supposed to increase the session duration of your app. But during user interviews, you discover it’s doing the opposite! The benefits are gone, and the project needs to change.
Or, let’s say you’re expanding your product into a new market and need to capture 30% of the market for your investment to make sense. However, two months into your six-month project a major competitor releases a product that’s clearly better than yours.
In the typical triple constraint, you could still finish the project to scope, budget, and timeline. However, the final product won’t do what you want it to. Again, you need to weigh the benefits against the success of your project.
Project constraint #6: Risk
Finally, risks are a part of every project. Yet, while it’s commonplace for project managers to create risk management plans to help identify and mitigate them, what’s less common is to set a threshold of how much risk you’re willing to tolerate.
At a certain point, a negative risk with high impact and probability is worth an intervention:
- You can try to find a mitigating response
- You can close the project down as the chance of the risk isn’t worth continuing to ‘spend’ resource on it
- You can readjust your risk tolerance in the same way that you might adjust the budget or deadline during the project
By thinking about risk as a constraint, you clarify what the project stakeholder/owner is and isn’t willing to do and can intervene earlier.
Working with the triple constraint: 5 ways to find creativity within limitations
You probably see these constraints as limitations, elements that get in the way or hold you back from finishing a project. However, with the right approach, limitations can be liberating.
Awareness of the six constraints of project management is only the first step. Once you know what you’re working with, it can empower you to think differently and look for unique solutions.
Here are five ways to use typical constraints to take your product to the next level.
1. Decide that you don’t have to (or want to) be ‘first to market’
Companies are often willing to lower scope, increase their budget, and take on additional risks just to be first to market with a product. But the truth is that it’s rarely the first to launch who succeeds.
With Planio, we've often taken the (unusual) approach to compromise on time. As CEO Jan Schulz-Hofen explains:
“At some point quite early on, we realized that we couldn’t be the ‘first to market’ or the early innovators in the project management field. And we've accepted that we don't have to.
“Starting from there, we wanted to focus on a quality product first and build and maintain it with a high degree of (cost) efficiency. As Planio is bootstrapped, we've never had VC millions to spend.”
Freeing yourself from the tyranny of the timeline allows you to be more creative with your approach.
Another example (but at a wildly different scale) is Apple. The iPod wasn’t the first MP3 player. And the iPhone certainly wasn’t the first smartphone. However, what both of those products did was optimize for scope and quality over all else.
Rather than rush to ‘get in’, Apple waited for the market to settle and then built the best version possible.
2. Understand your true priorities and work from there
Constraints can also bring clarity about what’s most important to your company or client. Instead of being overwhelmed by options, discuss which constraint to focus on. Then, adapt your plan accordingly. For example:
- If cost is the biggest priority: Adjust the project deadlines, scale back your scope, and agree upon a quality threshold that will let you finish the most without pushing the budget too much.
- If time is the biggest priority: Discuss adding more resources (i.e., budget) and cut back some of the scope or quality threshold to make sure you have the flexibility to hit your deadline.
- If the scope is the biggest priority: Clarify how you’ll add to the scope, set up thresholds for flexible timing, and decide how you’ll increase resources as more deliverables get added.
3. Use constraints to boost creativity
In your projects, constraints can be stressful. But when you identify them early on, they also allow you to get more creative with how you’ll approach your project.
As research has found, when teams face scarcity in time, cost, or other resources, they give themselves the freedom to act in less conventional ways–because they have to! As the study’s authors explain:
“The situation demands a mental license that would otherwise remain untapped.”
How many times have you discovered an easier way to approach a problem just because you dealt with an unmovable deadline? Or found more efficient ways to work because your budget was lower than expected?
It may seem counterintuitive, but a lower budget might help produce more innovative new products. But this only happens if you’re aware of the limitations and give yourself time to brainstorm new ideas.
With the right approach, limitations can be liberating.
4. Force yourself to examine the ‘true’ value of a project by its constraints
Just as cost constraints can increase innovation, too many resources can cause teams to work on the wrong things or get complacent about why a project truly matters.
As Angelo Baratta writes in The triple constraint: A triple illusion:
“A poor mental model prevents progress and the Triple Constraint has done just that. It influences how we measure projects. We have used the measures of delivered functionality, actual cost, and schedule versus planned for as long as can be remembered. Yet, despite the best efforts of many, we continue to achieve relatively poor project results.”
Instead, move away from vanity metrics (like time and cost) and recognize quality and benefits as the best signs of success.
5. Lower your scope and find the value of compound interest
As every Agile team can attest to, there’s power in consistently shipping products (rather than waiting until everything’s ‘perfect’). When faced with a large number of constraints, ask yourself, what if we did less more often?
Or, as author James Clear writes, if you want to hit your goals:
“Reduce the scope. Stick to the schedule.”
By choosing time as your most important constraint, you force your team to ship, learn, and grow at a rate that can help you overtake the most well-funded companies.
Every project has constraints. It’s how you use them that counts.
Constraints can be a source of stress. Or, they can be the perfect excuse to look at your work through fresh eyes.
By understanding the basics of the triple constraint of project management (and the additional elements we’ve listed), you can not only ensure your project gets completed but that you’re working on the right things in the first place.
More than just another theory that can help with project planning, how you deal with constraints can change the entire outcome of your project.