Agile and the PMBOK
From many sources both in and out of the PMI there is a general consensus that the PMI is moving toward a more flexible and agile-type project management philosophy. PMBOK version 4 has words throughout which reflect that tendency. However, the PMI and PMBOK are aimed at all project managers, not only IT project managers so explicit endorsement of agile software development mechanisms would be inappropriate since most of the practices only apply to software development. A lot of non-IT project management can only be done in a linear or waterfall fashion, such as construction. Even in IT many projects such as rewiring a facility for wireless connectivity or upgrading a server farm must be done in a phased approach. Projects other than software development that lend themselves to the iterative, agile approach include marketing programs, "soft" R&D, any project that includes artistic considerations such as web content development, annual reports, producing a movie or television show, mounting an art exhibition, etc. Basically any project where the outcome is not explicitly clear can benefit by applying some agile tenets of iteration and incremental delivery. Where the outcome is clear and the requirements are hard - say, a space shot or shuttle launch - linear, non-agile is much more applicable. The PMI must walk the tightrope between the two approaches to define general project management practices that apply to all so that the PMBOK doesn't have statements of condition, "In projects like this, do this, else in other projects do this other thing". Perhaps someday the PMI will produce two sets of PMBOKs