After adding so much information to the aptitude test, there was a bit of difficulty interpreting the test results. In addition to that, a vast majority of test takers were deemed as being under qualified based on their test results. This is why the percentile change was made. It ensured that a 50% actually correlated with a person doing better than 50% of the test takers. Those revisions have worked hand-in-hand with the preparation of the armed forces.
I would easily recommend this book to some people who are looking to solely study from the book, but also have no intentions of using the online practice questions. considering this book is from 2013 i discovered after it was delivered to my home. That being said there is no place for this book on the Dummies web site, and you cannot access the practice questions which you have paid for. Waste of money.