GMAT Official Guide 12th Edition

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GMAT Official Guide 12th Edition: An Overview
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Problem Solving
      
Data Sufficiency
      
Reading Comprehension
      
Critical Reasoning
      
Sentence Correction
      
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.

Not Radically Different
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.

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Difficulty Distribution
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 are repeats, as shown by a few correspondences in the middle.

Moving up the numbers, we see that the removals and the additions essentially correspond for most of the problems. Some “Medium-Easy” problems were removed, but they were replaced by Easy and Medium problems. The big discrepancy comes at the Hard end of the 11th edition. A batch of difficult problems was removed but not replaced. This accounts for the decrease in the overall number of Problem Solving problems.



A few relatively long stretches of problems were left unchanged. Generally, problems were removed or added in very small groups or individually.

Qualitative Observations
While there are several interesting and well-written new problems, the content of the Problem Solving section has not fundamentally changed.
The only shift truly worth noting is relative to Data Sufficiency. Since the number of Problem Solving problems has fallen (and many hard problems were actually removed), the GMAT may be moving in the direction of increasing the number of Data Sufficiency problems on the test.

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Topic Distribution

The proportion of problems in various topical categories has not changed substantially. The most significant change is that problems classified as Fractions, Decimals, & Percents have decreased somewhat in number. However, this very slight decrease does not mean that this topic has become less fundamental. Remember, slight variation is to be expected.

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GMAT Official Guide 12th Edition: Problem Solving
<< Back to 12th Edition Overview
            
Overall Changes
Which Problems Changed?
For an exact list of differences between the 11th and 12th editions, download the Problem Solving Problem List.The 11th edition has 273 Problem Solving problems (including 24 Diagnostic problems). In the changeover to the 12th edition, 75 problems were removed, leaving 198 repeats (including all Diagnostics), and 56 problems were added, yielding 254 Problem Solving problems in the 12th edition.


Among the problem formats, Problem Solving has the lowest proportion of new problems (22%). This section also decreased by 19 problems, a larger decrease than any other question format. (At the same time, Data Sufficiency increased by 19 problems.) These changes could reflect a slight shift toward Data Sufficiency on the Quantitative section of the GMAT.

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Difficulty Distribution
Observations

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 are repeats, as shown by a few correspondences in the middle.


Analysis

In the Data Sufficiency section, primarily Easy and Medium-Hard problems were removed; however, problems of all difficulties were deleted. In some cases, groups of 4 or 5 problems were removed or preserved at a time. Additions were made at all levels of difficulty, but not quite as many at the highest end.


Qualitative Observations
Several of the new Word Translations problems require that you keep track of 3 or 4 variables. Sometimes, you are given variables (often with subscripts, such as p1 and p2). In other cases, you must name the variables yourself and/or keep track of them in a table.
Many new problems impose constraints on variables. Often, variables are restricted to positive values explicitly (x > 0) or implicitly (x is the tax rate). A few problems impose an integer constraint as well (x is the number of cookies). As you solve for the variable – or, better, as you determine whether you can solve – remember to take these constraints into account. For instance, a quadratic equation may have two solutions, but if one solution is negative, it may be invalid. In this case, you would then have sufficiency, because only the positive solution is valid.
Many new problems require manipulation of inequalities in some way, even though the number of problems classified as “Inequalities” has decreased. The GMAT may be shifting this topic to more of a word-problem format. In most of the new 12th edition problems, the variables turn out to be restricted to positive numbers (see the previous point). In fact, the GMAT has removed many inequality problems that required you to deal with both positive and negative cases in the same problem.

Many new problems require statistics knowledge and skills. Topics such as weighted averages and medians continue to grow in importance.

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Topic Distribution


Analysis

The number of Word Translations questions (word problems of various types) has grown significantly, particularly among the Statistics and non-specific Algebraic Translations topics. Meanwhile, the number of pure Algebra problems (especially Inequalities and Basic Equations) has fallen substantially.



The GMAT has a number of different obstacles at its disposal to hide what information is needed to solve Data Sufficiency problems. This analysis suggests that the GMAT may be shifting towards word problems as the preferred Data Sufficiency obstacle. Furthermore, the GMAT may be shifting away from pure Algebra as the preferred obstacle.



However, we must caveat that you should not over-interpret this change. Some variation is to be expected. Also remember that you generally need pure Algebra skills to solve Word Translations problems. After you've translated the word problems into algebra, you must often use algebraic manipulation to complete the analysis.