All my research leads me to believe that a good understanding of ITTO's is key information to know for the PMP Exam. I have been using this tool along with my studies. I like the different modes as they can be used to enhance learning proficiency. I start in study mode to gain the basics. The immediate feedback allows for personal correction and more effective on the spot learning. Once I have studied the topic I can then test my myself in an additional 2 different ways. When you can pass in the confuse mode, you should have the material mastered. Periodic review at this point is a great way to reinforce and maintain what was learned. Great study, learning, and review tool.