Project Management Triangle: Overview of Triple Constraints

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Apr 15, 2024

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Before we deep dive into the Project management triangle, let us know what project management is? Project Management is the combination of tools, processes, people, and technology to control and manage the projects in such a way that it produces high-value products or services that meet the expectation of the customer. 

There are various project management methodologies in the market such as Prince2, PMBOK, Kanban, Agile, Waterfall, XPM, Scrum and lean, etc. As project managers, we need to put in time and effort to pick and choose the correct methodologies and framework for our project and our organization. Moreover, the projects come in different shapes and sizes, we need to fit the project into one of the methodologies or frameworks that is right and produce the maximum results. 

The world is very competitive and we need to produce the goods or services that are faster to the market, high in quality, takes less lead time, fewer overheads, and less cost with maximum profitability. Therefore the project management office assigns the responsibility of the project to the project manager, and companies prefer certified project management professionals for these tasks than the person who is not certified. Thus the project manager is in constant pressure to perform to manage and optimally control the projects.

What is the Project management triangle?

The project management consists of triple constraints of project that influence the projects; those are cost, scope, or quality, and the time. 

For example – Consider a scenario where the project has gone into some issues and the delivery time has increased. Now there are three ways to look into this, 

  1. Increase the cost of the project so that you can bill the customer accordingly or 
  2. You can put more resources so that the delivery time can be managed or 
  3. Increase the time with the consent of the customer. 

These types of things happen all the time. Sometimes the scope changes due to pressure from the customer. In these cases, the project manager must take appropriate decisions with acceptance from the project board. There are again the 3 constraints the cost, scope or quality, and the time. You as a project manager must do a lot of trade-offs and take the optimal decision which will not influence the project negatively. You need to focus on all the 3 constraints and if you leave sight of anyone then all the 3 affects the project negatively. That is why the 3 constraints of project which are dependent on each other are called as triple constraints of Project management triangle. The diagram below shows the Project management triangle.

Project Management Triangle

What is the Iron Triangle of Projects?

The Project management triangle is sometimes called as Iron triangle of project management. There is always a tug of war between these 3 project management constraints which adversely affect the projects. This means that all three are interrelated. Fixing the scope or quality will impact the other 2, that is more time and increase in cost. 

Thus, if you fix 1 thing than the other 2 have to move. There is no way that all the 3 comes into stable existence. That is why it is also called an iron triangle. Suppose you are designing a website for the customer then customer having said the scope and in quick time delivery, this would affect the cost. If customer fixes on quick time and costs it will affect the scope of what you want on the website. If the customer fixes the scope and the costs, then it will affect the time to delivery.  

6 Variables of the Iron Triangle Project Management

The 6 variables of the iron triangle project management triangle are as follows.

The 6 variables are Risk, Schedule, Resources, Budget, Quality, and Scope. Please look at the diagram shown below.

Project Management Triangle

It shows how the 6 variables of the project triangle are influencing each other. As shown in the diagram the scope is interrelated to schedule and Budget and vice versa. Similarly, the risk is interrelated to resources and quality. 

This means that change in one of the parameters will adversely affect the rest of the 2 parameters and in turn the whole diamond itself. This diagram is also known as a project diamond based on its appearance. 

There is a constant tug of war between all the 6 variables of the project diamond.

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Common variations of the project triangle

The common versions are described below,

Project Management TriangleIn this version, the quality is separated from the scope and moved to the center of the triangle. So there is a clear difference between the quality and the scope. Here the scope is deliverables and specifications, so any change in the sides of the triangle will affect the quality adversely.
Project Management Triangle

In this version the people are brought to the center and it is called as four variables of project success. Here if the people are not considered then the project will fail even in the presence of good organizational structure, better plans, and proper controls, etc.

3 deliverables and specifications of the triangle are cost, schedule, and quality, compromising one would affect the people in the center adversely.

Project Management TriangleIn this version, the scope is replaced with specifications and quality with people. This is because the performance or the specifications can be negotiable than quality as quality can be defined as "fit for purpose". In such cases the quality cannot be negotiated.

Use the Iron triangle this way

The project manager has to decide on the start of the project, on what is the most important out of the 3 constraints and what the next one is and so on. This can be decided while talking to the customers and while fixing the benefits and project negotiations. Fix what are the goals and objectives and then come up to the conclusion on 3 to 4 main objectives of the project. For example, if one of the most critical things is the cost then only the most critical change request needs to be approved. And if the critical thing is quality then we can have variations on the cost and time, etc.

However, having said that, out of the 3 project management constraints the most important is the scope. Even if cost and time can be adjusted then the team can start the projects. Managing the scope creep is the most important thing as it can adversely affect the project. Also due to fluctuations in the project scope, there might be sudden changes in the project that needs to be accommodated keeping the cost and time intact.

One of the key aspects is the data-driven decision making by the project manager to manage the Project management triangle.


As we have seen what is the Project management triangle and that the project manager’s responsibility to manage and control the projects to successful completion is the key. Data-driven decision making is very important and knowing the various project management methodologies is the key. Now, we recommend you take the online training with StarAgile which provides you the necessary knowledge by solving real-world examples in the course. StarAgile conducts online training on PMP Training and other management training with case studies, simulation, games, and role-plays. Click on the link to explore more and to enquire about the training registrations and for more details. 

Happy Learning!!


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