That's a good question. Let's just say that I did not study material that was not addressed in the PMBOK or the PMI Code of Ethics, and I still passed. I noticed that I missed several questions on the Oliver Lehmann 175-question mock exam that came from additional resources, and when I went to look into the links that the answer key provided to those resources, they were broken, because PMI no longer maintains that library resource. So I said forget it.

I can think of one exception: employee motivational Theories X, Y and Z were asked on several mock exams so I took five minutes to learn about what they are. I may have seen a question about that on the exam, but I'm not sure (mock and real questions start to blur together). I also did not review the additional practice standards that PMI publishes (
www.pmi.org/pmbok-guide-standards/framework
). I stuck to materials published by the prep course I took from Global Knowledge, materials from Cornelius Fichtner's PM Prepcast (the curriculum from this website) and some supplemental material that helped to illustrate/delineate the concepts in these materials. Hope this helps! Good luck!