The Triple Unconstraints – A model for success


Some of the worst projects I’ve ever overseen delivered on time, to budget and to scope. It sounds ridiculous I know, especially given that many organisations have a passion for using these three factors to determine whether a project has been successful or not. 

But none of these factors talk about the behaviours required by the project manager to be successful or the collective responsibility required by the stakeholders to work together harmoniously to get the work done.

I blame the Triple Constraints or ‘iron triangle’ for this. Actually, that’s wrong. It’s more accurate to say that I blame the people who continue to focus on the triple constraints as a means of measuring what a successful project should look like.


For those of you who haven’t seen the triple constraints, here they are:



No-one knows who came up with this model but we do know that it’s been used since the 1950s. It’s likely genesis is in the construction or aeronautical industry. Essentially, it’s an equilateral triangle demonstrating that each of these factors are as important as each other and that collectively they determine the quality of the product(s) being delivered.

When I became a project manager in the late 1990s it was one of the first things I was taught: ‘Colin, here are the things that will restrict you from doing the best job you can.’ Nice start.

What we used to say – and draw on whiteboards for disengaged sponsors – is that in times of change only two of the sides can remain fixed at any one time. That is, if one of these factors changes, then at least one other factor will be affected by it. ‘Pick two’ we used to say. 

Want to add more scope? Then more time or money may be needed.

Want it delivered quicker? Then more money may be needed or else you need to reduce the scope

Want to do it for less money? Then the scope may be impacted.

You get the idea.

However, we used this model in a time when projects were done to people, not with them and whilst a project manager’s job is to manage these (and other) competing demands, the definition of success is – and should always be – the satisfaction of the stakeholders and project team in relation to the service being provided to them.

Some of the best projects I’ve had the pleasure of overseeing didn’t focus on time, cost or scope. They had happy stakeholders, working in a vibrant culture, all the way through. Of course, that meant keeping an eye on time, cost and scope, but it’s much much more than that.

Some took more or less time. Whilst some spent more or less money. The outcome, however, was always the same. Stakeholders who got what they needed to solve the business problem that they had and a project team that become role models for how good projects should look and feel. What was constant throughout these projects was (and continues to be) the Triple Unconstraints. Those things that make the job of a project manager easier, not harder.


The Triple Unconstraints looks like this:



In order for any project to be successful, then a project manager must do all of these really well.

Who they are – Self-aware project managers know what they’re good at and what they’re not. They relentlessly self-develop and ask questions to continually improve who they are. They have vision, values and know their stuff, both technically and professionally. They see value in doing things in the right way. Plans and registers are maintained and reports are always of good quality and on time.

How they behave – Well behaved project managers understand that their position brings with it the need to role model what leadership looks like. They’re empathetic, humble, inclusive, encouraging, approachable and driven. They know how to communicate to every personality and take all of the blame and none of the credit. They take the time to actively listen to others and continually ask for feedback.

What they build – A project manager’s first and most important job is to build a team. They put in thought, energy, enthusiasm, time and money (often their own) to ensure this is done well. The team is united prior to planning and remains so throughout. The project manager delegates appropriately, makes time for new ideas, manages poor performance and ensures that every success is celebrated. The team is respectful, collaborates effectively, provides honest feedback and takes responsibility. Others want to join this team!

For years, organisations have done their best to dehumanise project management and make the measures of success all about the very things that change in projects! Namely the triple constraints of time, cost and scope. 

Only through the Triple Unconstraints can projects and project managers be truly successful. How many sides of the Triple Unconstraints are you or your project managers doing well right now?

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