When considering the difference between waterfall and agile, does the methodology of a project impact the length of the project?

Sergio beat me to it. Agility has more to do with organizational culture than with project management. We're focused on PM here so we sometimes forget there's more to it than what lies in our realm. But this is the reason I can't embrace the talk of "Hybrid" agility. You're either agile or you aren't. Perhaps it would be more appropriate to say you're either becoming more agile or you aren't.

Sorry to get hung up on words.

Back to the topic, I don't think there's a mathematical reason why an iterative life cycle project would always be be faster or slower than a predictive life cycle project. Like many things, it depends on context. If you are repeating a similar project plan repeatedly, then there may be value in the predictive (i.e. "waterfall") approach. You can quickly queue up the people and resources you need and start, and you won't need to stop until you're complete.

On the other hand, if your project is new, complex, and has a great deal of unknowns, then you'll probably have an advantage with an iterative life cycle within an agile culture. This is because you can establish an empowered team to collaborate with your customers and/or users and answer important questions over the life of the project. A similar team using a predictive approach will still be in the planning stages while the iterative team has already delivered their first product increments and testing their biggest assumptions.

The "Agile vs Waterfall" arguments always get more complex than this, but strictly speaking in terms of project completion, I can't say that one life cycle is always faster than another.

Sergio beat me to it. Agility has more to do with organizational culture than with project management. We're focused on PM here so we sometimes forget there's more to it than what lies in our realm. But this is the reason I can't embrace the talk of "Hybrid" agility. You're either agile or you aren't. Perhaps it would be more appropriate to say you're either becoming more agile or you aren't.

Sorry to get hung up on words.

Back to the topic, I don't think there's a mathematical reason why an iterative life cycle project would always be be faster or slower than a predictive life cycle project. Like many things, it depends on context. If you are repeating a similar project plan repeatedly, then there may be value in the predictive (i.e. "waterfall") approach. You can quickly queue up the people and resources you need and start, and you won't need to stop until you're complete.

On the other hand, if your project is new, complex, and has a great deal of unknowns, then you'll probably have an advantage with an iterative life cycle within an agile culture. This is because you can establish an empowered team to collaborate with your customers and/or users and answer important questions over the life of the project. A similar team using a predictive approach will still be in the planning stages while the iterative team has already delivered their first product increments and testing their biggest assumptions.

The "Agile vs Waterfall" arguments always get more complex than this, but strictly speaking in terms of project completion, I can't say that one life cycle is always faster than another.

Wade,

I like your 'You're either agile or you aren't'.

Would argue any good project manager is agile, as they have to react on deviations of the plan and changing project environments.

No @Thomas. A project manager is agile because she/he can run faster than they stakeholders when things go wrong....jejejeje, sorry for the bad joke. Just trying to add something, what you stated is Lean, is what Lean provides to organizations. Agile is one step forward. Agile is not about reacting only. Agile is about to anticipate. All this is getting thanks to agility organizations can achieved thanks to use Agile. Because of that knwoledge is the other magic ingredient in Agile.

Sergio, agree with your description of agile being also anticipating.

A project manager is anticipating anyhow, if they are agile (receptive to changes) or not. Anticipation is reflected in planning, estimation, risk management, forecasting and much more stuff right out of the PMBoK. It is about giving stakeholders a perception of the future and therefor hope and trust. If a PM is not doing this, they are failing.

Wade,

I like your 'You're either agile or you aren't'.

Would argue any good project manager is agile, as they have to react on deviations of the plan and changing project environments.