In this research paper (see at https://engineering.purdue.edu/cdesign/wp/?p=1748), we investigated which functional decomposition methods work best for developing an understanding of a product’s functions (i.e. which method best helps you figure out how something works?)  We evaluated a two formal methods, as taught in design textbooks, and the informal method of simply naming what comes to mind.  We found that there was no measurable difference in the outcomes between any of these methods, which itself is significant, potentially challenging nearly a century of tradition.

We believe these results are either due to the cognitive loads on the students (the task is hard because there is too much to keep track of) or the formal methods not having any real benefit.  The data and conclusions in this paper are investigated deeper in an upcoming journal paper.