GMAT OG Verbal Review, 2nd Ed: Sentence Correction
Like the other verbal question types, Sentence Correction hardly changed from the 1st edition to the 2nd edition.
The biggest change was in the proportion of two topics. In the 2nd edition, there are significantly fewer questions focused on Idioms and significantly more questions focused on Modifiers. Idioms remain an important area in the 2nd edition, however, both as the primary focus and as the secondary focus of questions. Moreover, the implication of this topical shift is not fully clear, so you should continue to prioritize topics according to the layout in SC study materials (such as our Strategy Guide), as well as according to your own strengths and weaknesses.
Qualitatively, very little has changed. A few new Idiomatic wrinkles have arisen (e.g., the use of “thus” and further uses of “appear”). In addition, a couple of new high-numbered Modifier problems employ absolute phrases, a special appositive phrase that can modify an entire thought. This type of phrase (which is already covered in our materials) has been relatively uncommon. However, none of the new problems represent fundamental shifts in SC content.
The 1st edition had 113 Sentence Correction problems. 27 problems were removed, leaving 86 repeats. Then 27 problems were added, yielding 113 problems—the same number as before.
Classifying Sentence Correction problems under one category is a simplification, since most problems test more than one topic. That said, we have identified the primary topic tested by each problem and computed the total in each category, as shown below.
The proportion of problems in a couple of categories has changed significantly. The number of Modifier-focused problems has grown from 12 (11% of total) to 20 (18% of total). Meanwhile, the number of Idiom-focused problems has fallen from 17 (15% of total) to 8 (7% of total). The relative proportions of problems focused on other topics only shifted slightly.
Again, be careful not to over-interpret this change. The GMAT folks could be correcting a prior imbalance or simply adding in a fairly random batch of questions that happened to be skewed toward Modifier questions.
This graph displays the difficulty level of problems that were removed, repeated, and added. Excluding problems in the Diagnostic exam, higher-numbered problems are more difficult, according to the GMAT. On the left, red problems were removed from the 11th edition. On the right, dark-green problems were added to the 12th edition. Light colors represent repeated questions.
Problems were removed from the 1st edition at all levels of difficulty (as measured by problem number), but significantly fewer at the high end. In fact, none of the highest 23 problems were removed.
Meanwhile, problems were added roughly evenly across all difficulty levels.
The difficulty of various topics, as measured by position, shifted somewhat. The most substantial changes were among “GMC” (Meaning and Concision) problems, which fell in difficulty, and among Verb Tense/Mood/Voice problems, which rose in difficulty. Odds & Ends has a very small sample size, so the large swing of its position is not that meaningful.