Help my Sentence Correction scores are decreasing!

Throughout various GMAT discussion groups, you'll often find students discussing a common phenomenon in which their Sentence Correction accuracy seems to DECREASE after they've learned all of the grammatical rules tested on the GMAT. In this article, we'll take a look at why this phenomenon occurs.

To set things up, I'd like you to first consider a question I used to give my high school math students:

What's the next term in the following sequence: 1, 11, 21, 1211, 111221, 312211, ?

Aside: Once you've tried the question, you'll find the correct answer (and explanation) here.

The interesting thing about the above question is that, in a class of 12th graders, there MIGHT be 1 student who correctly identified the next term, whereas a class of 10th graders would typically see 2 to 4 students get the right answer, and a class of 8th graders would see 6 or more students get it. It seemed that the younger the students, the more likely they were to solve the question. I even posed the question to my friend's 8-year-old son, and he produced the correct answer within a minute. 

The reason the older students had a harder time answering the question is that they simply knew too much math. As a result, they were testing a wide variety of complex theories involving logarithms, modular arithmetic, etc., whereas the younger students (especially my friend's son) weren't encumbered by so much mathematical knowledge.

The same concept applies to students studying Sentence Correction. Before learning any of the grammatical rules, students typically rely on their ear to eliminate wrong-sounding answer choices. After these same students learn dozens of grammatical rules, they find themselves mysteriously finding something wrong with practically EVERY answer choice. As a result, their accuracy decreases.

So, how do we avoid this phenomenon?

For starters, when eliminating answer choices, try to name the grammatical rule you're basing your decision on. More importantly, be sure to identify the specific words that are breaking whatever grammatical rule you're citing as the issue. For example, if you're citing Subject-Verb disagreement as an issue with a sentence, then you must identify which words are breaking the rule.

It's also important to mention that a decrease in Sentence Correction accuracy may reflect some misunderstandings you may have about a particular grammatical rule. So, keep track of the question types (e.g., dangling modifiers, tenses, conditionals, etc.) you’re answering incorrectly. If you find that you're struggling with certain question types, you probably need to go back and review that topic.

Finally, it's useful to simply know that this phenomenon exists, and that, with more practice, your accuracy will certainly improve.