Why are the triple constraints important in project management?

So what does the iron triangle look like when it’s applied to projects?

Quality deals with how good our product is, as judged by the customer, client or consumer. It will help us define what we’re going to do and what we’re not going to do.

Time has to do with our schedule; we have a deliverable that is due on a specific date, so scheduling activities helps make sure that happens on time.

In cost, we have a limited amount of money to accomplish building the deliverable by the due date. If we run out of money before the end of the project, where will we get it?

To work out why the triple constraints matter, let’s take a look at one element at a time. What happens if you drop the quality of what you build? The first thing that will happen is the customer will not accept it. The second thing that happens is the project cost will increase, and finally we won’t be able to deliver on time. We have to respect the schedule, the required quality of deliverables, and we have to respect the cost.

Managing the triple constraint

Think of the triple constraint as the boundaries in which you can work. Just as restrictions enhance creativity, the triple constraint provides a framework that everyone in the project can agree on. These constraints drive the project forward while allowing for adjustments as needed when issues arise.

Managing a project is often a series of trade-offs and compromises to keep things moving towards a successful completion. The triple constraint is a model that helps project managers know which trade-offs are going to work and what impact they’ll have on other aspects of the project.

As a project manager, you need to be able to manage the triple constraints effectively. To do this, you should ensure that you:

  • Read the Project Initiation Document (PID) carefully. It tells you what you need to deliver, when delivery is due, and what budget has been allocated to the project.
  • Make clear firm plans for the sequence of activities within the project in the form of a Work Breakdown Structure (WBS).
  • Monitor your progress throughout the execution phase of all the activities to make sure you are adhering to the triple constraint.
  • Seek stakeholder and customer acceptance at the start, and continue to communicate throughout the project.

If you follow these steps, you’ll protect the triple constraint and deliver the project that everyone wants.

Your task

You are now going to critique the iron triangle model. Conduct some research for yourself on the theory of the triple constraint by looking for an academic article online to read.

Imagine you are managing a project of a small extension to your house. Ask yourself:

  • Does using the triple constraint limit your understanding of projects and their chances of success?
  • Are there other key elements that you think are missing from the model?

You can also relate this to your own experience managing projects – do you think there are elements that you would add?

Post your ideas and thoughts in the comments and have a look at what others are saying.

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This article is from the free online course:

Project Initiation

Coventry University