Let’s consider this for a moment, a five-legged stool. Can you see where I am going?

Though I agree the model is flawed, I don’t agree that making it more complex is the answer. So in the hopes of keeping the model simple, I suggest the flaw lies in the legs themselves.

I offer these 3 legs instead:
- Speed
- Value
- Performance

Reflect on those for a moment and let me know what you think. I believe these dimensions factor in speed-to-market, benefits and risk (risk being a subset of performance). I will likely write a post on my blog, inspired by this discussion, so please comment there as well.

Steve Romero, IT Governance Evangelist
http://community.ca.com/blogs/theitgovernanceevangelist/

@www Thanks for the compliments. You’re right, in some respects the triple constraint ends up being a constraint for the project manager. I have come across some PMs who focus solely on the triple constraint and some that don’t at all, both are incorrect.

@vincent I’m not sure I understand the question correctly but if I understand it correctly then I would say that no matter where the change comes from, inside or outside, the impact should be assessed.

@simon Yup, I couldn’t agree more. Turning around and saying “Is this project still viable?” is the last question anyone wants to hear, including the PM! But the question must be asked.

@Sam and Bryan H Thanks

Regarding the Benefits. In Prince 2 it is I guess the Business Case, that needs to be reviewed as necessary. In your example when something change should it be outside or inside the project.

In the end that’s ONE more thing to deal with as a Project Manager, not only making sure that execution goes OK but that the project still make sense!…

Lot’s of talk (and writing) about the Triple Constraint right now — ahead of the new PMBOK version increasing the “legs” of the triangle.

This is one of the better pieces.

There have always been more constraints in projects than three. It’s refreshing to see people (and PMI) starting to think this through in a creative way on the path to a better model.

Thanks,

—www

Your humour needs to have the model applied to it too

Here’s what I experience though – decisions/course corrections when a project is mid-way are often taken without considering one, or even two, of the other corners. Then when low-quality is experienced, or increased costs, etc… guess what? Project sponsors are surprised!

Why are they ignored?

Because it produces an unpalatable answer.
Or because it shows a lack of heroism.
Or because it isn’t exciting.
Or because decision makers are lazy.

The corners are generally well considered during project planning, but in my experience, they soon get forgotten as a triple constraint once the project is under way.