Your choice of methodology defines how you work and communicate. What methodology you choose will depend on your team, project-type, and project-scope. Every project is unique. Some projects are relatively straightforward and predictable. Others are highly complex and risky. Each requires a different approach when it comes to how the project should be managed. Applying the same amount of project management rigor to every project is wasteful. Despite this, many organizations and project managers apply project management dogma without deviation instead of tailoring their efforts appropriately.
Size designations put projects in perspective -used to determine the extent and degree to which structured management methodologies must be applied for any given project. Project management practices are meant to ensure that projects can be completed in a structured fashion - on time, on budget and producing expected results. As such, project size variations must be considered as management practices are developed and applied. Project managers may have some technical know-how but also have the important task of taking high-level corporate visions and delivering tangible results on time and within budget.
Developing a project's approach recognizes that all projects are not the same—requirements will likely change, schedules are compressed and often come with imposed deadlines, budgets are limited, and stakeholders will have varying degrees of involvement.
If the project manager is knowledgeable in one particular project management methodology, it is difficult to step back and consider an entirely different approach. Project managers often attempt to force a project to fit a given methodology because that is what they are most familiar with. Project managers need to expand their thinking to embrace different forms of project management. The project manager along with the project management team should tailor the project management approach to fit the business environment, the risks, and the complexity of the project.
The reason that different companies use different project management techniques is due to many factors. The biggest factors are project complexity and project size. The reasons are that more complex projects may need different project management techniques compared to less complex ones. This is probably due to the project having multiple simultaneous parts being worked on requiring and the capabilities of a larger company to work on bigger projects.
