A question posed by some folks preparing for the GMAT is: is it enough just to study GMAC’s Official Guide, or should I use other GMAT books?
Here’s what I would say to that. If you are the type of student who regularly scores well the above the 95th percentile on standardized tests, and if the difference between, say, a 770 and a 790 doesn’t really mean that much to you, then by all means, just use the Official Guide. For example, neither Leonardo da Vinci nor Johann Wolfgang von Goethe probably would have needed more than the OG if they were of a mind to take the GMAT. Of course, that advice applies to a precious few percentage points of the entire population.
For everyone else, for all the ordinary folks out there who want to maximize their chances on the GMAT, the Official Guide is an essential piece of what is needed to prepare, but it is not the whole story. Get more help.
If you don’t already know about the two free online forums, those are excellent places to pose questions, observe discussions, get advice, and in general see what other folks are doing to prepare. These two are:
1) GMAT Club: http://gmatclub.com/
2) Beat the GMAT: http://www.beatthegmat.com/
If you are a good self-starter who learns well from books, and you have a bit of discretionary income to spend, then the Manhattan GMAT series are often considered the most comprehensive resource in print.
If you learn better from video than from a book, if you need to hear & see an explanation in real time, then for about the price of the Manhattan GMAT books, and for much much less than the price of any course you could take, you can sign up for Magoosh. We have over 200 lesson videos, explaining both the content and the strategies you will need to succeed on the GMAT, and we have over 800 practice questions, each with its video explanation of the answer. If you grew up a child of television and/or the computer, if you have a propensity toward being a Youtube junkie, then Magoosh is GMAT test prep designed precisely for you.
Magoosh also provides prompt customer support, and we will answer any question from any official GMAT source (the OG, GMATPrep, etc.) That makes Magoosh the ideal complement to whatever other GMAT test prep you are using.
So, to summarize: yes, if you are a freakishly bright person, then just stick with the OG and you’ll be fine. For the rest of the world —- for all the people who, through no fault of their own, happen not to be Leonard da Vinci but still want to do as well as they can —- get more help. Use the forums, and if you learn well from video, then seriously consider how Magoosh can help you prepare.