In the project world, seldom, if ever, do you see any discussion about using multiple project methodologies. When you think about it, is every methodology good at enterprise management? Is every methodology scalable? 
When we think about the variety of projects that are there for our use, Waterfall, Scrum, Agile, Kanban, and a host of others, why should we be limited to one? Even in a single project methodology, like Kanban, Corey Ladas made the claim in Srumban that you never create the same Kanban board twice. Jim Benson of personal Kanban fame talks about a Kanban Board Walks through an organization and how at each Kanban Board they were all slightly different. This exemplifies the idea that you have to make the process your own but does it enforce that the methodology should also be your own for better results?
I am going to pick on Kanban, even though it is my favorite project methodology. I have listen to arguments in the past from Scrum people that Kanban was not scalable but is the Scrum of Scrum really best suited for managing Scrums?
A project is created to reduce uncertainty and to carry out a mission. Most of this believe by following a project methodology that we reduce this uncertainty and, of course, allows us to execute a mission. I have been part of a few unsuccessful projects before, and a few might have failed because of poor planning or even the methodology. However, the ones that stand out, the tough ones that were delivered on time and on budget seem to have succeeded because of the people involved not the methodology. Even more often it was because of the project lead.
Should a project lead determine the methodology for a project as part of the project requirements or scope statement? A lack of familiarity or maturity of the group may dictate a different way. We may want more of a time base iteration or even a resource driven project. In most businesses, we have a variety of reasons for a different project methodology. We need to ask ourselves just a few questions like this:
- What is the project experience of the project members?
- Are all project members familiar with the current technology?
- Does it include Customers?
- What type of project is it?
- Low or high tech?
- Strategic or operational?
- Consumer, Public, Government?
- Production, Operations, Knowledge Work?
- Regular time, Fast Paced?
- Critical, Non-Critical?
- What is the breadth of the project?
- Is the project simple or complex?
Are present methodologies adaptable enough? Should we even expect that or want that? Should we always be trying to create a consistent methodology for everything and everyone? Or, should project planning be looking more at different methodologies than it does?
P.S. In the sales and marketing world, do you consider the typical Sales Funnel as sort of a project plan? Does one size fit all?