The project management triangle visualizes the problem of “triple constraints”—the need to balance scope, cost, and time in order to maintain a high-quality final product. Every project manager who has known the frustration of trying to keep their team productive with too little time, not enough budget, and an impossibly large scope has experienced the project management triangle in action.
No single variable of the project triangle can be changed without making tradeoffs with the other two points of the triangle. It’s the project manager’s job to balance all three elements in order to keep their project within budget and on deadline while still fulfilling the specifications of the project’s scope.
Below we break down and examine the three points of the project management triangle, how they’re related, and how project managers can keep them in balance to ensure project success.
The project management triangle is made up of three variables that determine the quality of the project: scope, cost, and time.
The triangle demonstrates how these three variables are linked—if one of the variables is changed, the other two must be adjusted in order to keep the triangle connected. If the triangle breaks—that is, if one point is moved without adjusting one or both of the other points along with it—the quality of the project will suffer.
It’s a project manager’s job to balance the three points of the triangle to achieve the best possible quality while staying within budget, on deadline, and adhering to the project specifications.Read: How to effectively manage your team’s workload
There are two types of relationships at play in the project triangle. The first is the relationship between scope and the two other project variables. Scope is directly proportional to both time and cost, which means it moves in the same direction as those factors. When scope increases, time and money must also increase in order to tackle a larger project.
The second type of relationship is the relationship between time and cost, which is an inversely proportional relationship. These two factors move in opposite directions. If costs need to be cut, then deadlines will have to be extended; but if you encounter a sudden time crunch, you’ll need extra budget to adjust to shorter timelines.
These two relationships can't be altered—nothing you can do will make it possible to change one variable without causing a corresponding change, either directly or inversely, in the other two points on the triangle. This is why the project triangle is often called the iron triangle of triple constraints. No matter how strong a project manager is, the iron triangle can't be bent to their will.Read: The beginner’s guide to the theory of constraints
In order to keep all three elements in check, the project manager must have a deep understanding of each individual variable and where they have the opportunity to be flexible to accommodate changes throughout the project.
Scope is the “size” of the project in terms of the quality, detail, and magnitude of the project’s deliverables. As the size of the project increases, it will naturally require more time and money in order to complete.
Elements of project scope might include:
Quantity of finished product(s)
Strength (e.g., the number of simultaneous users an app can support)
Level of detail
Number and complexity of features
Be careful to avoid “scope creep” by finalizing project plans and getting project stakeholders to sign off on everything before production begins.
For purposes of the project triangle, cost isn’t limited to literal dollar amounts. Often referred to as “resources,” this triangle point includes all of the tools, equipment, and support required to complete the project.
Elements of scope might include:
Number of team members
Equipment and facilities
The cost/resources variable includes more than just literal money, but generally everything within this point can be tied back to a financial value. For example, adding employees requires additional budget for salaries; taking an opportunity to keep offices open longer requires additional budget for hours of electricity usage.Read: Your guide to getting started with resource management
When adjusting for time, keep in mind that the amount of time is as important as the type of time you're measuring. Tradeoffs can require extended deadlines, adjustments to team calendar software, elimination of planning phases, and more.
Elements of time might include:
Overall project timeline
Hours worked on project
Internal calendars and goalposts
Time allotted for planning and strategy
Number of project phases
If budget is cut or scope is increased, you’ll need to find smart ways to compensate by loosening one or more of your project's time constraints, whether by extending deadlines, adding hours, or making other schedule adjustments.Read: 5 project controls and where to implement them
When someone finds a new way of doing something that increases cost-efficiency or speed, this adjustment can be made without a corresponding change in the other points of the project management triangle.
For example, someone on your team finds a way to improve the functionality of a tool necessary to your project. This tweak to your production methodology may allow you to achieve more within a shortened project schedule or work with a smaller project team.
Similarly, any updates to the production process that can help standardize flows and cut down on decision-making time will allow your team to work more efficiently without sacrificing quality. Investing in management tools like standardized sales templates or project management software will cut down on wasted time and costs without impacting quality or scope of a project.
Now that you understand what the project triangle is, here are a few tips on how to put it to good use in your day-to-day work. It's a good idea to reference the five project management phases as well to identify areas of overlap.
The central concept behind the project triangle is that no project can be successful with three rigidly fixed points. At least one point needs to be flexible, so that you know where you have room to make adjustments when they become necessary.
If your priority is staying on budget, an unexpected obstacle can be dealt with by pushing back your deadline rather than hiring more staff to troubleshoot it quickly. If your client’s timeline is rigid, it’s wise to get extra budget pre-approved so you have the resources to address challenges without delaying production.
Once you know the limits and priorities for your project, communicate them clearly to your client and any stakeholders in the project to prevent unmet expectations and unhappy owners.
In industries frequently affected by unforeseen complications, like construction and engineering, contracts will include special elements that help the project manager get all stakeholders on the same page before the project begins. These elements include:
Contingency budgets approved ahead of time by client
List of common potential delaying factors (weather, natural disasters, local events, etc.)
List of frequently used plans of action for each delay that estimates cost and time that would need to be added in case of each contingency
Give stakeholders a clear understanding of what sorts of events may occur and how they might impact costs and timelines, and get the client’s preferences recorded so you can reference them later when you need to make an adjustment in your project triangle. When the project is finished, there will be no confusion as to why those adjustments were made.Read: 12 tips to effective communication in the workplace
Once you’ve set an agreed-upon plan of action that includes potential budget, schedule, and scope adjustments for different potential circumstances, be sure to keep all stakeholders informed of any changes and predictions throughout your project.
If a supplier informs you they’re low on a necessary resource, update your customer and project owner to let them know that there’s a potential for delay. If you run out of your resource, your stakeholders will be apprised of the situation and ready for whatever adjustments you need to make. If you don’t run out of the resource, you and your customer will both feel more confident knowing that you were prepared for all scenarios.
There are many approaches to project management that prioritize different project variables and, as a result, have different project triangles. Below we’ve sorted seven common project management methods into those that prioritize low costs and those that prioritize time saved.
Projects with stricter budgets and more flexibility in timeline will benefit from these project management methods, which prioritize efficient resource usage.
Waterfall: project phases are completed sequentially, so timelines must be flexible since a delay in one phase will require adjustments to all subsequent phases
Lean: prioritizes minimal costs and resources, allowing for longer timelines or scope cutbacks to keep project within budget
Project Management Body of Knowledge (PMBOK® waterfall): variation on traditional sequential waterfall process that applies standards defined by The Project Management Institute’s Project Management Body of Knowledge to improve process efficiency
In situations where time is of the essence, these project management methods can eliminate unnecessary downtime and expedite project processes to keep teams moving swiftly.
Agile: prioritizes flexible processes, so teams are prepared to adjust to change requests with adaptations that require minimal time or cost increases; teams employing this approach often use specific agile management software
Scrum: a specific type of agile project management seen most often in software development that utilizes facets of Scrum methodology like sprints and daily team touch-bases to minimize time lost to work-in-progress stages
Kanban: uses continuous, high-visibility collaborative processes to minimize work-in-progress time; teams employing this approach often use specific Kanban software
Scrumban: combines collaborative and continuous nature of Kanban process with Scrum’s daily team reviews to better minimize work-in-progress time
Of course, the goal of every method is to find the optimal balance between low costs, quick speeds, and high quality. But since the project management triangle requires prioritization of at least one variable, these methods skew in the direction of whichever variable is most important to the team.
Though the iron triangle and its system of triple constraints may seem limiting at first, once you learn how to apply them in your enterprise project management process, you’ll find that these tools will actually make your projects run more smoothly. With a better understanding of your limitations and flexibilities ahead of time, you can avoid costly setbacks.
In addition, the iron triangle will help ensure you select the right project management software, create processes, and set up your production so that your team can hit the ground running. After that, there’s no telling what you’ll be able to accomplish together.Plan projects with Asana