Being in the need of finding a methodology to develop software, either because you or your your job place lacks one or to replace the current one, is a nice and complicated task. I believe there are three main concerns you should identify a priory and make a plan to successfully tackle them: the time you’ve got to accomplish the task, the way you’re going to find the right one for you and the political issues this change will bring into otherwise messy but calmed waters.
The first is a constraint you find in every project and is the one that takes you out of the ideal scenario where you build the same project with all the candidate methodologies and then compare metrics. This concern is why you need to put some trust in other people’s success stories. The second concern, the matter of this post, tries to identify what are you going to compare so you know the methodology suits better for your needs. Finally, you have to realize that not because you and your closest teammates believe it’s time for a change everybody else does, some other people may just love the way it is now.