According to Jeff Atwood (Coding Horror), software development is a religion. Wow, frankly I hope not, because I am quite ignorant when it comes to theological matters. A major issue with human/social studies and practices is that it is so hard to get close to anything that would be considered as scientific knowledge and not pure erratic opinions. Yet, it's not because it's hard to produce science that it isn't worth trying.
The recipe of scientific knowledge production includes a very fundamental ingredient: reproducibility. If somebody else can't, providing enough time and efforts, reproduce what you have observed then there is no hope to produce any science. For software development, the current situation is quite troublesome. Indeed, the pace of change in software development is totally dwarfing the speed of scientific production. By the time, a scientist would be able to produce a rigorous scientific analysis of software development (5 to 10 years), the software world itself would have changed so much that the study, at the time it gets published, would be already totally obsolete.
The second factor that complicates the production of knowledge is that software engineering actors do have very strong interests to defend biased positions. Science involves publishing both positive but also negative results (see the Journal of Negative Results - Ecology and Evolutionary Biology for example). Do you think that Microsoft, Google or [insert here your favorite IT company] are really going to publish anytime soon reports explaining how and why they failed miserably while developing some particular products? From a marketing viewpoint, you need to appear brilliant no matter how bad (or good) things might be in the office.