A chair with four or more legs can wobble. But with three legs, it’s impossible.
This sense of balance makes triangles inherently appealing. Maybe that’s why a triangle is the best way to illustrate the challenges faced by every project manager.
As a project manager, you’re pulled in three different directions:
- Your product has to stay under budget and avoid resource drain.
- It has to be shipped to the customer fast.
- And it has to be, you know, good.
There’s a word for people who can deliver products quickly, cheaply, and rich in features: genies. Or maybe fairy godmothers.
Everybody else needs to make trade-offs. When that time comes, and it will, the project management triangle model is supremely helpful.
In this article, we’ll tell you everything there is to know about the project management triangle so that you can keep your balance when things get rocky.
What is the project management triangle?
The project management triangle is a way to visualize the three competing demands on a project manager: time, project cost, and scope.
Using the project management triangle, a project manager can understand trade-offs between the three project constraints they’re acting under.
It’s not clear who first described the project management triangle, which is also called the iron triangle, the scope triangle, or the triple constraint model. But it’s been in use since long before the modern software era.
To understand the iron triangle, imagine an object sitting dead in the center. You can’t move it toward one point without moving it away from the other two.That’s the basic assumption underlying the PM triangle: paying more attention to one area leads to worse results in the other two.
Okay, but how does the project management triangle work?
A more cynical project manager might choose to phrase it this way: “Fast, cheap, good. Pick any two.”
If you prioritize time, you’ll tend to get the project done fast. However, either the scope can’t be nearly as large or you’ll have to shell out more money to try to accomplish your work in less time.
If project cost is your top priority, you’ll probably finish under your project budget. But you could end up having to hack scope or miss your desired deadlines, since you’ll either be employing fewer or cheaper people (or both).
If you focus on scope, you’ll likely ship a high-quality, feature-rich product — though you might risk delaying release and going over budget in order to incorporate all the bells and whistles.
The project management triangle is a model used for making predictions. Its usefulness varies directly with the amount of information you have.
Understanding the time corner of the triangle starts with knowing your clients. They will almost certainly not be OK with an expected delivery timeline of “whenever we get around to it.”
While most clients will be at least a little flexible, time is most often the hard point around which your other decisions must revolve — especially if they’re used to a traditional project methodology.
Money is an unusual corner of the triangle, since spending more doesn’t always guarantee better results. For example, you can hire more staff to try to get a project finished faster, but an overstaffed project team can actually harm efficiency and quality if not managed with extreme care.
Project budget is a decision that revolves around how much the client is paying you and how much profit you’re targeting. You need to determine how much you can spend and whether you or the client will tolerate going over-budget.
Scope needs to be tightly controlled in light of the other two project constraints. It’s the one a project manager often has the most leverage over.
While it might go against your principles to ship a product that’s less than perfect, the project triangle illustrates why it’s sometimes necessary. The alternative is scope creep: a project that keeps growing forever, yet never feels finished.
Related questions answered
Still want to know more about the iron triangle? Here’s the 4-1-1 on 3 related and commonly asked questions:
What are the 6 constraints on a project?
Some project management consultants extend the triple constraint triangle to include 3 more constraints. Constraints 4 through 6 vary depending on who you’re listening to, but the most common answers are quality, benefits, and risk.
Quality is similar to scope. You’ll often see the two used interchangeably, but they’re not identical.
Scope is how much you’re trying to do, while quality is how well you’re trying to do it.
Suppose you’re grilling a steak. The scope of your project is simple: render the meat edible. But within that scope, the quality is variable. Some people want it rare, others medium-well.
Make sure to pick a quality that pleases all your steakholders (we’re deeply sorry, but we had to do it).
Benefits can also be expressed in terms of customer satisfaction. Using benefits as a constraint recognizes that the developers and customers don’t always have the same standards for what constitutes a successful project.
Maybe your company wants to deliver a product with tons of features, but your customers just want one that’s easy to use.
Maybe your leadership is most concerned with saving time and money, but your customers are demanding quality.
A successful project manager never forgets that their decisions about balancing time, money, and scope are also constrained by what the customer wants.
Lastly, there’s risk. This is one only the best project managers think about.
A common beginner mistake is to seek zero risk. A project manager might fear getting blamed for actions that harmed their company, so their solution is to never do anything risky at all.
Consider, though, that the least risky way to complete a project is to spend a lot of time, money, and energy to design, develop, and test it. Risk is a trade-off just like all the others: if you zero it out, you’ll send every other constraint through the stratosphere.
That’s why we have this handy risk register template to help you track and manage all your project risks.
What is the Agile triangle?
The Agile triangle updates the traditional project triangle to incorporate Agile project management philosophies.
If you’re not familiar with Agile, here’s a quick refresher: it’s a modern project management philosophy that focuses on short release cycles, fast decision-making, and tight communication.
It looks a bit like this:
Agile thought leader Jim Highsmith suggests 3 different points for the project management triangle: value, quality, and constraint.
Value refers to the benefit the project provides for the customer, and in some interpretations, to the development team as well.
Quality means the inherent positive traits that make the product awesome: its features, solutions, innovations, etc. Recall from our steak example that intrinsic quality does not necessarily equal value for the customer.
Constraint lumps together all three constraints from the old-school triple constraint iron triangle — the limits in terms of project cost, project schedule, and project scope.
Highsmith’s point with the Agile triangle is that a project manager should not plan out the entire project with an eye toward what’s constraining it. Focus on what’s possible before you plan around what’s realistic.
This scrum planning template can help you plan your next Agile project while keeping the 3 constraints top of mind.
What are the core components of a project plan?
Answering this question will help you move from the abstract modeling of the project management triangle to the concrete reality of a project plan.
The first thing you’ll need is a project scope statement. This defines your goal in as much detail as possible.
- BAD: “I want to build the world’s greatest gingerbread house.”
- BETTER: “I want to build a gingerbread house that incorporates icing and gumdrops.”
- BEST: “I will build a two-story gingerbread house that incorporates edible decorations such as icing and gumdrops, but no inedible decorations such as Legos or string.”
See the difference? The best project scope statement defines not only what is part of the project, but also what isn’t. It also includes a success factor: when the house reaches two stories and includes edible decorations, the project can be considered complete.
Next, you’ll need to manage the time constraint with a clear schedule. Say your holiday party is in two weeks, so you need to have the gingerbread house finished by then.
That’s a hard deadline — you can’t move it, so you’ll have to work around it. It means you’ll have to lower your scope a bit if you realize you can’t realistically build that fancy of a house in that amount of time. .
Finally, lay out a clear budget. You’ll need a certain amount of money for supplies, and a bit extra left over for incidental expenses and unexpected costs (like gumdrops you dropped on the floor).
Since your time is a bit constrained, you may decide to bring on a contract employee (your neighbor’s daughter) to finish icing the roof. That increases the budget, but makes the timeframe manageable.
Your scope, schedule, and budget are the backbone of your project plan, and they all inform each other. That’s the true meaning of the iron triangle.
To discover what else is in a project plan, check out What is a Project Plan?
Or get started with this project planning template:
Even a seasoned project manager can feel overwhelmed by the number of decisions they need to make each day.
Visuals like the project management triangle model are useful because they give your thoughts a framework to latch onto.
That’s why we built the monday.com project management software around visual templates that are easy to customize. Not only can you find a model that helps you make your project management decisions, you can also customize it as your thinking evolves.
Get started with a monday.com template like Projects Overview today.