Should we redefine the traditional project management triangle into a “project management square”?

Alaa, interesting question. I don’t think we necessarily need to redefine the traditional project management triangle into a square. The triangle represents fundamental constraints that have always governed how projects are delivered. It’s not meant to capture every dimension of success, but rather the core trade-offs that must be balanced in execution.

If we start adding sustainability as a fourth dimension, the question becomes: where do we stop? Project success already depends on additional factors like quality, risk, stakeholder satisfaction, and long-term value. Expanding the model into a square could oversimplify a much more complex reality or lead to an ever-growing shape that loses clarity altogether.

That said, I do agree that sustainability is increasingly critical and arguably non-negotiable in many contexts today. Rather than reshaping the triangle, it may be more effective to treat sustainability as an overarching principle or lens that influences all three constraints. For example:

• Scope can explicitly include sustainability requirements and outcomes
• Cost can account for lifecycle impacts, not just upfront expenses
• Time can reflect longer-term thinking, including durability and future implications

In this sense, sustainability isn’t just another constraint but it’s a mindset that reshapes how we define value and success across the entire project lifecycle.

On a final note to summarize, instead of turning the triangle into a square, it might be more useful to evolve how we interpret and apply the triangle in a modern context where success is not only about delivery, but about responsible and lasting impact.