Think back to college for a second. You might remember how exhausting it was to try to fit in everything it took to earn good grades, have a social life, and get your eight hours of sleep — all at the same time.

Perhaps you studied hard and partied, while living off an IV drip of coffee.

Or perhaps you slept and partied, but didn’t attend all that many classes?

In any case, you could never seem to be well-rested, well-studied, and well-socialized at the same time. When you focused on 2, the other one kind of… got away from you.

Project management is the same way, thanks to pesky little project constraints. When you try to loosen one constraint, the other 2 become more prominent.

In this article, we’ll dive into the most popular model for representing project constraints, show you why this model is now obsolete, and introduce you to a new way of measuring restrictions.

We’ll finish up by explaining why project constraints are different from assumptions, dependencies, and risks.

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What are project management constraints?

The traditional project management theory of constraints is called the Triple Constraint Theory.

Its 3 constraints are scope, time, and cost:

  • Scope: Scope determines the breadth of the project. It includes the client requirements, and the features, functions, and tasks needed to meet those expectations.
  • Time: Time is self-explanatory — the amount of time required to complete a project or a portion of work. Whether it’s set sprint lengths or fixed milestones, every project has some kind of time constraint.
  • Cost: Cost involves the financial and other resources required to complete the project. Even the largest business doesn’t have bottomless pockets; projects have to be completed within a certain budget in order to be profitable.

All three constraints are linked. When you change one project constraint, you affect the others.

For example, if you increase the project scope (perhaps you have to add more features to a product), you’ll likely have to extend the project timeline or increase the budget.

Or perhaps you need to cut costs. You’ll then have to change your project schedule or decrease the scope to make it work.

Lastly, if you cut the timeline, cost or scope must shrink accordingly.

Traditional project management theory represents this give-and-take relationship between each project constraint with the “Project Management Triangle,” also known as the Triple Constraint Triangle:The triple constraint triangle

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Each point represents one of the constraints. If you pull the triangle in one of the constraints’ directions, one or both of the others must shorten to compensate.

Quality is often put in the middle of the triangle to represent how constraints can affect project quality.

For example, if you increase the scope of the project without extending the timeline or increasing the budget, your end result’s quality will suffer.

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Does the triple constraint triangle still work today?

The short answer is no, the traditional triple constraint model doesn’t work well today.

It’s too restrictive, too simplistic, and doesn’t account for other project constraints.

Organizations today must be able to adapt to the fast-changing market environment, shifting customer needs, and advancing technology.

Project management thinkers and institutions have created their own project constraint models that better represent the factors impacting a project.

For instance, the Project Management Institute’s enhanced 6-constraint model. The 3 new constraints (added to the traditional 3) are as follows.

  • Quality: The new model recognizes quality as an independent project constraint. This essentially represents the deliverable’s characteristics.
  • Benefits: Benefits represent what sort of value your end product will deliver to your organization.
  • Risks: Risks can be both positive (opportunities) and negative (threats).

Author and software engineer Jim Highsmith, a pioneer of the Agile project management methodology, saw that traditional constraint models didn’t work for companies that needed to be nimble.

He applied Agile to the Triple Constraint Triangle, creating the Agile Triangle (which is the model we at prefer).

The 3 constraints of the Agile Triangle are as follows.

  • Value: Value is the extrinsic quality of the deliverable. It’s the value the customer experiences from the product.
  • Quality: Quality represents continuous delivery of value to the customer based on what the customer needs.
  • Constraints: Constraints combines the traditional Triple Constraints Triangle constraints (time, cost, scope) together.

The agile triangle

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The Agile Triangle allows organizations to change their work based on the value the customer receives, rather than pre-defined metrics. You can shift focus to delivering the best product and experience for the customer.

What makes constraints different from assumptions, dependencies, and risks?

Constraints aren’t the only things you should consider. You should also look at assumptions, dependencies, and risks. Each of these concepts is related to constraints but has some differences.

Let’s break them down, shall we?

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Assumptions are things you can’t establish as true right now, but are likely to be true based on your analysis.

Now, you have to be careful not to be too bold with your assumptions. After all, you can’t see the future.

Consider the following when making assumptions:

  • Confidence: How confident are you that each assumption will be true?
  • Project impact: How much work will you have to do to fix problems should your assumptions prove wrong?
  • Lead time: How long will it take for you to find out if an assumption is true or false?

Say you’re creating a timeline for a new project. Past similar projects took 2-3 months, but mostly leaning towards 2. Erring on the side of caution, you can assume this one will take 3 months.

If similar projects all took 3 months, though, you’d be more careful about this assumption.

Keeping your project team in the know about assumptions helps everyone stay on the same page. With, for instance, you can list all your assumptions as you create your project plan right within the project planning template: project planning template


Dependencies exist when one task relies on the status of another task.

There are 2 kinds of dependencies.

  • Internal dependency: Internal dependencies refer to interlinking tasks, activities, or even resources that are within your ability to control. One of the most common internal dependencies is when you’re required to finish one task before performing another. For example, you can’t test a feature before you develop it.
  • External dependency: External dependencies are factors outside the project on which project delivery depends. Project managers usually can’t influence external dependencies. For example, you may be unable to move forward on a project until a government agency approves your product at a certain stage.

Dependencies can cause bottlenecks, so they often influence task scheduling and resource allocation. You may put more resources towards Task A to get it done faster if Task B is dependent on Task A. lets you set and automate custom due date dependencies to make sure your team doesn’t do things out of order. You can also choose from a library of present dependency “recipes”.

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The project timeline template works quite well as a starting point, since dependencies so often influence how long a project will take. project timeline template


Risks are uncertain events or circumstances that, should they happen, could positively or negatively impact ability to achieve specific project objectives.

As mentioned earlier, risks are a constraint under the 6-constraint model, so they can be a type of constraint. But not all constraints are risks, and some risks may not be constraints.

Risks pose a threat to project success if negative. You need a strong risk management process to deal with project risk.

Thanks to’s program risk register template, you can manage, identify, and mitigate risks with ease. You can categorize and assign owners to each risk, track the likelihood of risks occurring, monitor risk status, and more. program risk register

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The project manager can only do so much with what they have. It’s on them to figure out how to best manage project constraints while delivering a result that provides value to the customer.

Although the Triple Constraint Model may no longer be as useful, constraints still rule the day when it comes to project management.

Which means they need to be managed. Can we recommend our project tracker template to get started?

If you want a Work OS platform that is as nimble as you need to be, sign up for today.

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