Here’s Why You Should Interleave Your GMAT Studies (and What that Means)
Recently, I wrote a post about how to get the most out of Official Guide (OG) problems during your studies. In that article, I discussed how to interleave your GMAT studies and I’ve got more to say on this strategy that’s of crucial importance to your studies.
What is Interleaving?
In a nutshell, interleaving is a way of mixing up your studies. For example, let’s say that you’re about to start studying the Fractions chapter of our Fractions, Decimals, & Percents (FDP) Strategy Guide. It’s only 8 pages long, so you should just read the whole thing straight through, right? (Note: if you actually have this guide, pull it out right now and follow along below.)
Not so fast! Interleave your activities, even though you’re going to stick to this one topic, and make this learning stick better. For example, the section on Numerator and Denominator Rules (page 48) may warrant making a few flash cards. Stop right now and make them!
A page later, you may realize that, while you now understand how to convert mixed numbers to improper fractions, you don’t yet feel totally comfortable actually doing so. Don’t just keep reading! Pull out your Foundations of Math book, look up the relevant material there (hint: look at the table of contents for the Fractions chapter), and drill the skill for 5 or 10 minutes right now.
Then, head on back to the main FDP strategy guide Fractions chapter. The point here is that you’re not just reading the entire chapter straight through and then trying the problems at the end. You’re intellectually curious and you’re pushing yourself as you work through the material: do I really understand that? How can I test myself? Is there something here that I need to memorize? How am I going to get that into my permanent memory? If I don’t feel entirely comfortable with something I just read or practiced, what can I do to try to learn it better right now?
How Else Can You Interleave Your GMAT Studies?
At other times, interleave topics. Let’s say that, today, you’ve been focused on learning fractions and percents. Now, you feel ready to try a set of OG problems. Don’t just put fraction and percent problems into that set! What else do you need to practice? If you were studying Digits and Decimals a few days ago, and Algebra last week, toss some of those into the set, too.
As you get about halfway through your GMAT studies, start choosing some problems randomly, so that you don’t even know what you’re getting. Worried that you’ll choose something you haven’t studied yet? That’s actually a good thing! You also need to study what you’re going to do when you don’t know what to do. Can you recognize (without blowing too much time) that you don’t know how to do this one? Do you have the discipline to cut yourself off and make a guess? Those are important skills to practice for the real test. (You can read more about setting up OG problem sets in the article that I linked to at the beginning of this article.)
Another way to interleave topics is to focus on strategies or characteristics that cut across content areas. Practice Smart Numbers or Testing Cases, regardless of whether the problem is algebra or geometry. Practice story problems—who cares whether this one is Rates and the next one is Percents?
You might even interleave Quant and Verbal! Spend an hour on Quant, then switch over to Verbal for a while, then come back to Quant.
Are There Any Drawbacks to Interleaving? When Should I NOT Use It?
There is one seemingly major drawback. But, interestingly, this apparent drawback turns out to be a point in favor of interleaving.
In my last post on this topic, I linked this video from Dr. Robert Bjork, a UCLA professor who specializes in human learning and memory. The big payoff is in the last 90 seconds (it’s only 6 minutes long). If you haven’t already watched it, go do so now. (Yeah, it’s a little dry at points. But you want to go to grad school! Stick with it. 
)
The more traditional form of study, where you stick to one topic or one type of activity, is called blocking. This is how most people study. As Dr. Bjork explains, most people feel that they are learning more when they block their study. However, they are actually learning more when they interleave their study!
Essentially, interleaving feels harder because you are stretching your brain more. I could go jog around the block or I could run. Jogging is going to feel a lot better, but running will actually give me the better workout.
I have to be careful: if I run too fast or for too long, I might injure myself. So you don’t want to interleave your GMAT studies to the point that your studies are so jumbled up that you have no continuity and can’t develop solid takeaways.
In my post about getting the most out of your OG studies, I talk more about this. When you’re first studying some new topic area or strategy, you do want to try a few questions of that type, so that you can solidify your learning. Don’t keep going and do all of the Fraction questions at once, though! Save most of them for mixed question sets, so that you can practice under more official conditions and interleave your studies, all at the same time!
Anything Else I Should Know?
A little learning science tidbit for you: vary up where you study as well. Scientific research actually shows that, while you’re learning, you’re internalizing things from your environment (sights, smells, sounds) that help you to recall the new memories you’re trying to make. If you vary up your physical location, you actually give your brain more varied ways to store memories, and this will help with your eventual recall.
Take-Aways
(1) Interleave your study topics. Don’t spend three hours working on Critical Reasoning Inference questions. Cross over into CR Strengthen problems (which can sometimes look like Inference questions) and Reading Comprehension Inference problems (which ask you to do the same kind of thinking). Toss in CR Discrepancy questions (which are in the same family as CR Inference), and if you run across a CR question that requires you to do some math thinking, maybe go look up something about that math topic as well!
(2) Interleave your study activities. Don’t do the same type of action or activity for an extended period of time. Have one thing to anchor your study period, such as a particular topic, question type, lesson, strategy, or chapter of a book. But move around among your resources: books, interactive lessons, videos, forums, flash cards, practice drills, GMAT-format problems, fellow students who are also studying for this exam.
(3) Don’t be fooled by the fact that interleaving feels hard and blocked practice feels good. Your brain should actually hurt a little—that’s how you know you’re stretching it! ?
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Stacey Koprince is a Manhattan Prep instructor based in Montreal, Canada and Los Angeles, California. Stacey has been teaching the GMAT, GRE, and LSAT for more than 15 years and is one of the most well-known instructors in the industry. Stacey loves to teach and is absolutely fascinated by standardized tests. Check out Stacey’s upcoming GMAT courses here.