Choosing Effective GMAT Practice Questions

One of my main goals with this site is to help guide you through the quagmire that is the commercial GMAT prep marketplace. There are some good resources out there, and there's a lot of garbage. Unfortunately, even if you find the best resources, you still may not use your time as effectively as you could.

Here are the two things that will help you use your time the most effectively when doing practice questions:

1. Choose realistic questions. Start with the Official Guides. After that, consider my questions, which are carefully patterned after those in the Official Guides for exactly this purpose.
2. Choose questions at the appropriate difficulty level.

The second one is much harder than the first. How do you know how difficult each question is? After all, you'd have to do it to know how challenging it is, right?

Yes and no. The quick-and-dirty way to solve this problem if you're using the Official Guide is to use certain sections of the book. For instance, in the orange book, there are about 250 Problem Solving questions. Very generally speaking, they steadily get harder from #1 to #249. That doesn't mean that #2 is a little bit harder than #1: it's far too approximate for that. But, if you jump in at #150 and you only get 2 of the first 10 questions right, that's a sign you need to back up.

If you want a more precise measurement of difficulty, consult my Guides to the Official Guides. (I hope I don't sound like an infomercial here: I've specifically created these resources because the need for them is so glaring.) In each one, I organize every single question into one of five tiers of difficulty. I do the same in each one of my problem sets, as well. When I work with students one-on-one, I often start them out at the lowest level, only moving up when they reach a certain degree of competence and comfort.

Regardless of which method you use, this will ensure that you work on the problems that are most useful to you. Since the GMAT is an adaptive test, you won't see very difficult questions unless you do well on the moderately difficult ones. Despite this, I know far too many students who spend all their time looking for the hardest questions they can find, spending hours learning the most arcane topics, when they would've benefited so much more by focusing on more basic skills.

That said, you don't need to master every level before moving to the next one. This isn't high school algebra, where you must drill every topic 100 times before you're ready for the following concept. Instead, shoot for about 70% at each level. In other words: when you can do 7 out of 10 questions correctly, confidently, and within a reasonable amount of time, you're ready to move to the next level.

If you increase the difficulty level sooner than that, you're wasting your time.

You may note the similarity between this article and my tip last week concerning probability on the GMAT. In general, students spend far too much of their study efforts on "sexy" topics: difficult questions, difficult concepts, the sort of thing they think they'll need to get a 700. Many of those people never build their basic skills to the point where their advanced skills matter one bit. As I've already said, it's a horrible waste of effort.

Knowing this, you can leverage your study time to get the best possible score. It may not be trendy, but be sure to learn the basic- and medium-level concepts (especially algebra!) inside and out before moving on to the challenging stuff. If this is obvious: great! In that case, you're already a step ahead of the competition.

About the author: Jeff Sackmann has written many GMAT preparation books, including the popular Total GMAT Math, Total GMAT Verbal, and GMAT 111. He has also created explanations for problems in The Official Guide, as well as 1,800 practice GMAT math questions.

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