Iron Triangle of Project Management | Scope, Time & Cost | Study.com

The iron triangle in project management is critical in determining the tradeoffs that need to be made to complete a project successfully. This will allow for a change of variables that can be adjusted to cater to those that cannot be changed. Project managers realize that they cannot get the results they want without making some sacrifices. The following example illustrates how the triple constraint triangle works. Julius hires a software development company to integrate credit card payments into his website. A week after signing the contract, he directed them to add a feature that could allow clients to pay using other mobile wallets. This move significantly increases the scope of the project, and after evaluating the request, the company gives him three options.

First, Julius should extend the deadline to allow the same number of staff to work on the project. Secondly, he can maintain the deadline but increase the payment to be made. This will allow more staff to be added to the project to complete it on time. Lastly, he can eliminate the extra feature and have the project delivered with the features that were initially requested. Any request by the client to expand the scope will result in a change to one of the other constraints. To maintain the same deadline, there would have to be an increase in cost. However, an increase in cost can be avoided by extending the deadline.

By monitoring all the factors in a project, a project manager can notice any issue that arises and address it instantly. These issues can include scope creep, where the team adds more features than originally requested, unexpected costs, or other factors that increase the chances of failing to meet a deadline. Once a problem is identified, one can decide the side of the triangle that can be changed and that needs to remain fixed. Those factors that can be changed will then be adjusted to resolve an issue at hand and optimize a project.

Other Constraint Considerations

The iron triangle has variations depending on the type of industry in which it is applied. However, the basic concept remains that changing one constraint will always require a change in the other two. The term budget is sometimes used to replace the term cost in the iron triangle. A budget is a better representation of the planned costs, including equipment, personnel, space, and materials.

Quality, risk, and other constraints that a team deems necessary can be added to the overall matrix and handled in a way that is similar to the other constraints. This makes it possible for the model to have more than three constraints. Quality is sometimes placed at the center of the triangle, and any change done to a side of the triangle affects it. For example, if a team is way ahead of the planned schedule, they can add more features or use the time to perfect the planned features. Additional scope and time imply that the output will be of higher quality. If a project runs long without an increase in budget or a reduction in scope, quality will be affected negatively.

Risks are unexpected events that have the potential to cause harm to a project. A proper plan ensures that risks can be anticipated, identified, analyzed, and acted upon in the course of a project. Doing so helps protect a project from factors that can be detrimental.


Sometimes quality is placed in the center of the iron triangle of project management

Triangle showing cost, schedule, and scope as vectors with budget in the center


Lesson Summary

Project management involves overseeing a project successfully using one’s skills and the available resources. Three factors are critical in project management. These are cost, schedule and scope. These standard parts make up the iron triangle of project management. The iron triangle is also known as the triple constraints since it includes the three factors which are considered essential for every project. It is also known as the flexibility matrix since the three factors are linked to each other in a matrix form. This makes it possible to differentiate them and determine the least flexible and the most flexible factor.

For example, an increase in scope to accommodate a new feature would require one to determine the constraint in the matrix that is most flexible and makes changes as appropriate. Each leg of the iron triangle can be changed to balance the changes made in the others. The term cost in this triangle is sometimes replaced by the term budget, which represents all the planned costs. Other constraints that can be included in the triangle are quality and risk. This allows the model to have more than three constraints.