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The 12th Edition: Inside Analysis

ManhattanGMAT has performed an in-depth examination of the 12th Edition. We've matched up the 11th and the 12th editions, classified every problem by topic, run the numbers, and drawn out the insights. Download the OG Problem Lists, which categorize new problems by question type, and read the analysis on this series of pages.

Purchase the OG 12th Edition

On March 13, the 12th Edition of the Official Guide for GMAT Review was released. We at Manhattan GMAT have analyzed the book in detail; here are our findings.

Only 1/3 of the questions are new. Out of 907 problems, 607 are repeats. The best way to look at the 12th Edition is as a source of 300 great new practice problems.

Much of the book is completely unchanged:

Most explanations for repeated problems have been untouched, though some have been improved.
The Diagnostic Exam, Math Review, Test-Taking Strategies and Directions are unchanged.
Excluding the Diagnostic Exam, sample questions are organized by difficulty, according to the GMAC – just as they are in the 11th edition.

The removed and added problems constitute a slight shift in the relative emphasis of certain topics, but the underlying content is essentially the same as that covered in the 11th Edition.

In fact, of the 300 new problems, some of the new Quant problems can be found in GMATFocus™ (both GMAC products).

It is important to note that you should not over-interpret the changes from the 11th Edition to the 12th Edition! Some variation is to be expected. Nothing in these changes suggests a notable shift in how students should prepare for the exam.

The 12th Edition has 19 more Data Sufficiency problems than the 11th Edition. Moreover, 47% of the Data Sufficiency problems in the 12th Edition are new. For other question formats, turnover is in the 22%-36% range.

In addition, the 12th edition has 19 fewer Problem Solving questions than the 11th Edition. These shifts may suggest an increase in the relative importance of Data Sufficiency, but this is not certain.

If you have been preparing with the 11th Edition, feel free to treat the 12th Edition as a source of additional practice. But you do not need to switch immediately. If your exam is near, you might consider mining the 12th Edition for a few new problems. But your time may be better spent reviewing practice problems you have already encountered, as well as doing online practice with GMATFocus, or practice exams such as ours.

<< Back to 12th Edition Overview

Which Problems Changed?
For an exact list of differences between the 11th and 12th editions, download the Sentence Correction Problem List.

The 11th edition has 156 Sentence Correction problems (including 18 Diagnostic problems). In the changeover to the 12th edition, 55 problems were removed, leaving 101 repeats (including all Diagnostics), and 57 problems were added, yielding 158 Sentence Correction problems in the 12th edition – 2 more than in the 11th edition.

The proportion of new Sentence Correction problems (36%) is very nearly the same as the average for all problems (33%).

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.

Sentence Correction: Distribution of Topics

The proportion of problems in various categories has changed, but only slightly.

The number of Pronoun and Modifier problems has risen somewhat, while the number of Comparisons and Idioms problems has fallen by a similar amount. Parallelism has increased by 2 problems. Otherwise, the net number of problems in various categories has remained the same. Parallelism is still the clear leader as a primary topic, but Modifiers replaces Comparisons in the #2 position.

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.

Sentence Correction: Distribution of Difficulty Level

Problems were removed from the 11th edition at all levels of difficulty. In some cases, groups of 3 or 4 problems in a row were deleted.

Problems were also added to the 12th edition at all levels of difficulty, but in an extremely regular pattern, with no more than 1 at a time. This pattern is the same as that for new Critical Reasoning problems.

The difficulty of various topics, as measured by position, shifted somewhat. The most substantial changes were among Comparisons, which increased moderately in difficulty, and Meaning/Concision, which fell in difficulty. Odds & Ends has a very small sample size, so the large swing of its position is not that meaningful.

Sentence Correction: Average Position / Difficulty

Like the other problem types, Sentence Correction has not changed greatly from the 11th to the 12th editions. Do not forget this point as you study the nuances of new problems.
The GMAT continues to look for ways to penalize unwarranted shortcuts. Certain awkward expressions are often but not always wrong, and the GMAT has included problems that force you to choose these expressions, such as being (in #101) or the fact that (in #83). Remember that the right answer is not necessarily graceful, but it must be grammatically correct.
Explanations for repeated problems have generally remained the same, but occasional changes have been made that may indicate a slight refinement in the GMAT's thinking on particular issues. For instance, the explanation for problem #7 in the 11th edition condemns the use of which in restrictive clauses and instead insists on the use of that. This problem has been preserved verbatim as #10 in the 12th edition, but now the explanation says that the rule against which in restrictive clauses is "controversial." As it turns out, none of the wrong answers in the problem fail solely on this basis. Nevertheless, with its new explanation, the GMAT has signaled that it will almost certainly never write wrong answer choices that can only be eliminated with the which rule.
A few idioms have been added or returned to the working lexicon of GMAT Sentence Correction. Some of these, such as not just X but also Y, are variations of well-known idioms. Of course, you must be extremely careful not to draw too many analogies with idioms, which by definition resist classification. For instance, one new problem (#140) uses the word dated, which must go with at, not to be, when you express an age: This fossil has been dated AT 10,000 years old, not TO BE 10,000 years old. In contrast, a seemingly similar word, estimated, must be used in precisely the opposite way with ages (This fossil has been estimated TO BE 10,000 years old, not AT 10,000 years old), as is tested by problem #27 (#21 in the 11th edition).

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GMAT Official Guide 12th Edition: An Overview

Not Radically Different

Data Sufficiency Has Grown

Transition If And When You’re Comfortable

The Official Guide, 12th Edition: Section By Section

GMAT Official Guide 12th Edition: Sentence Correction

Overall Changes

Topic Distribution

Difficulty Distribution

Qualitative Observations