Before adopting something, especially a new development process, Microsoft forms a task force or focus group to do some research. Following are some results of a case study done by some project managers at Microsoft in 2003. This is just one case study of the extreme programming practices to see if it would be viable for Microsoft to adopt, so take it for what it is worth. After studying a couple of companies that have used the extreme programming methods to ship a couple of products (whose names must be withheld for confidentiality reasons), this is what the task force came up with for recommendations:
The primary barrier was the name extreme. Agile development was a better term.
In general, extreme programming is believed to be useful for small- to medium-sized teams with fewer than 12 persons. It seems that if the development group is large or greater than 20 30 people, the quality of the code will suffer unless you have "extremely" good tools and processes that monitor all the extreme programming methods and you adopt all or none. The general consensus is that extreme programming is good for some projects and not so good for others. It depends on the project you are working on and the culture your developers live in, so choose wisely.