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GMAT Official Guide 12th Edition: An Overview

300 New Questions

On March 13, the 12th Edition of the Official Guide for GMAT Review was released.We 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 areunchanged.

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.

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.

DS has increased: 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.

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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.

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PS:Overall Changes

The 11th edition has 273 Problem Solving problems (including 24 Diagnosticproblems). 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.

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

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not mean that this topic has become less fundamental. Remember, slight variation is to

be expected.

Difficulty Distribution

This graph displays the difficulty level of problems that were removed, repeated, andadded. 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 Solvingproblems.

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),

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the GMAT may be moving in the direction of increasing the number of Data

Sufficiency problems on the test.

New Problem Solving Problems

2, 5, 13, 18, 23, 24, 27, 28, 37, 40, 42, 43, 45, 48, 50, 54, 58, 59, 60, 65, 66, 68, 69, 73,

74, 79, 81, 82, 83, 89, 90, 91, 92, 99, 105, 106, 107, 108, 109, 110, 117, 119, 124, 142,143, 146, 148, 149, 157, 159, 163, 164, 171, 197, 222, 230

DS:Observations

The 11th edition has 179 Data Sufficiency problems (including 24 Diagnostic

problems). In the changeover to the 12th edition, 75 problems were removed, leaving

104 repeats (including all Diagnostics), and 94 problems were added, yielding 198 DataSufficiency problems in the 12th edition.

Analysis

Among the question formats, Data Sufficiency has the highest proportion of new

problems (47%). This section also grew by 19 problems, much more than any other

question format. (At the same time, Problem Solving decreased by 19 problems.) These

changes could reflect an increased emphasis on this problem type.

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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.


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




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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.


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.

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Many new problems require statistics knowledge and skills. Topics such as weighted

averages and medians continue to grow in importance.

New Data Sufficiency Problems

4, 7, 8, 9, 13, 14, 17, 18, 19, 21, 22, 24, 25, 26, 27, 28, 31, 32, 33, 36, 37, 38, 39, 42, 44,45, 46, 48, 49, 52, 53, 54, 55, 57, 58, 59, 62, 63, 66, 67, 68, 69, 70, 75, 76, 77, 78, 79,

80, 81, 82, 87, 88, 89, 90, 93, 94, 97, 98, 99, 100, 101, 104, 105, 106, 109, 110, 111,

112, 115, 116, 117, 120, 121, 122, 123, 124, 128, 129, 132, 133, 134, 137, 141, 142,

147, 148, 151, 152, 157, 161, 162, 167, 168

RC:Overall Changes

The 11th edition has 158 Reading Comprehension questions in 27 passages. In the

changeover to the 12th edition, 45 problems and 7 passages were removed, leaving 113repeated problems and 20 passages (including all Diagnostic problems and passages).

43 problems and 7 passages were then added, bringing the total to 156 questions and 27

passagesalmost exactly the same as in the 11th edition.

Among the problem formats, Reading Comprehension has the second lowest proportion

of new problems (28%). New passages constitute a similar portion of the whole (26%).

Distribution of Questions and Passages

General vs. Specific Questions

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The General/Specific split has not changed very much. Within the Specific category,

there is a slight shift away from Detail questions (lookups) toward Inference questions,

which require not only a lookup but also some degree of interpretation or further

thinking.

Passage Length

Two long passages (>300 words) were replaced by two short passages (

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Passage Topic

The distribution of passage topics hardly changed. There are 2 fewer biology passages,

but we should expect some normal variation from edition to edition.


This graph displays the difficulty level of problems that were removed, repeated, andadded. Excluding problems in the Diagnostic exam, higher-numbered problems are




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Seven passages at all levels of difficulty were removed, together with all theirproblems. Moreover, two problems were removed from passages that were retained.

These problems contained statements or phrases labeled with Roman numerals (I, II,

III). Since no other problems contain Roman numerals, the GMAT seems to be

indicating that it is moving away from such problems.

No new problems were added to old passages. The only source of new problems is new

passages, which are distributed at all levels of difficulty.

Since questions must be listed together with their passages, note that easier passages

could have hard questions associated with them, and vice versa.

If we accept that the passages are listed in order of difficulty, then difficulty is

somewhat correlated with length and with topic in the 12th edition, just as it was in the

11th edition. High-numbered passages are more likely to be long; low-numbered

passages are more likely to be short. However, the correlation is far from perfect.

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Moreover, business passages tend to be lower-numbered. Biology and social science

passages are relatively evenly distributed, and physical science passages tend to be

higher-numbered. Again, though, this is a statistical pattern. Topic is not a perfect

predictor of difficulty or position.

These graphs look essentially the same for the 11th edition.

Are higher-numbered passages truly more difficult? You should regard this issue with

some degree of skepticism for the following reasons:

Passages have similar measures on other objective measures of difficulty besides length

and topic (e.g., words per sentence). Moreover, there is no significant correlation

between those objective measures and position in either the 11th or the 12th edition.

The effective difficulty of a passage depends a great deal on you that is, on your

personal comfort level with the topic. You are not expected to bring specific scientific

knowledge to bear on the GMAT. But if you are interested or become interested in

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the content of a passage, you will find that passage much easier to digest, whether the

passage is considered difficult or easy by the GMAT.


Reading Comprehension has not really changed. The content and style of the new

passages and questions is very similar to the content and style of removed passages andquestions.

As was mentioned earlier, Roman-numeral questions have been deleted. Since the

associated passages were retained, together with all the other problems, this deletion is

a fairly strong signal that the GMAT may be moving away from this sort of question.

However, there were only 2 such questions in the 11th edition; this type of problem was

never very important.

New Reading Comprehension Problems

1, 2, 3, 18, 19, 20, 21, 22, 23, 24, 25, 36, 37, 38, 39, 40, 41, 57, 58, 59, 60, 61, 62, 63,

76, 77, 78, 79, 80, 81, 103, 104, 105, 106, 107, 120, 121, 122, 123, 124, 125, 126, 127

CR:

Overall Changes

The 11th edition has 141 Critical Reasoning problems (including 17 Diagnostic



Critical Reasoning problems in the 12th edition the same number as in the 11thedition.

The proportion of new Critical Reasoning problems (35%) is very nearly the same as

the average for all problems (33%).

Topic Distribution

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The proportion of problems in various categories has changed somewhat.

Two minor question types have substantially increased in number: Analyze the

Argument Structure (from 3 to 13) and Evaluate the Conclusion (from 6 to 14). Analyze

the Argument Structure problems include boldface statement problems, in which 1 or

(usually) 2 statements within an argument are displayed in boldface, and you are asked

to describe the role these statements play within the argument. The GMAT has added 9such problems. Evaluate the Conclusion problems ask you to choose the best way to

evaluate the validity of a conclusion, e.g. what information would be most useful to

know. These increased numbers may indicate that the GMAT is emphasizing these

particular types of problems more than before.

Among major question types, Weaken the Conclusion has fallen the most in number

(from 51 to 37); however, it is still the most numerous question type. Both Find the

Assumption and Draw a Conclusion have also registered declines; in fact, in the 12th

edition, they are not much more prevalent than the growing minor types mentioned

earlier. However, Find the Assumption and Draw a Conclusion should still be classified

as major types, given their logical importance.






Light colors represent repeated questions.

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Problems were removed from the 11th edition at all levels of difficulty. Every instance

in which 2 or 3 questions were asked about 1 argument was eliminated. In some cases,

every question was removed; in other cases, one question was preserved.

Problems were also added to the 12th edition at all levels of difficulty, but in an

absolutely regular pattern, with no more than 1 at a time.

As for the difficulty of various question types, the average difficulty of Analyze the

Argument and Evaluate the Conclusion fell, because more problems of each type were

added throughout. Evaluate the Conclusion fell the most, since many low-numbered

problems of this type were added. Among the major question types, Find the

Assumption and Draw a Conclusion became moderately harder.

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The most interesting shift is the growth of the minor types, particularly Analyze the

Argument Structure, as mentioned above. Analyze the Structure problems were under-

represented in the 11th edition (in fact, only one boldface statement problem exists

and its in the Verbal Supplement, not the 11th edition itself). This problem type is

generally difficult, since the arguments are generally long and complex, and the answer

choices are often worded in confusing ways. Students should be sure to practice problems of this type. Also, Evaluate the Conclusion deserves additional attention,

although the new problems are concentrated in the lower (easier) numbers.

An interesting new structure appeared in one Explain the Event problem (#22). In this

problem, a plan is outlined, together with the result (the failure of the plan). Finally,

further information is provided. This further information allows you to rule out some

possible explanations for the failure of the plan.

Several new problems contain rather long chains of cause and effect (e.g., #49, 62,

112). Students will continue to need effective techniques for keeping track of complex

arguments.

New Critical Reasoning Problems2, 4, 7, 9, 12, 14, 17, 19, 22, 24, 27, 29, 32, 34, 37, 39, 42, 44, 47, 49, 52, 54, 57, 59, 62,

64, 67, 69, 72, 74, 77, 79, 82, 84, 87, 89, 92, 94, 97, 99, 102, 104, 107, 109, 112, 114,

117, 119, 122, 124

New Critical Reasoning Problems by Category

Assumption: 84, 107, 112

Conclusion / Inference: 57, 102

Strengthen: 14, 24, 32, 34, 42, 47, 67, 94, 99, 109, 119, 122

Weaken: 4, 19, 52, 82, 87, 104, 114

Argument Structure (BOLDFACE): 17, 29, 37, 54, 64, 77, 79, 89, 97, 117, 124

Evaluate the Argument: 2, 7, 12, 27, 39, 44, 49, 69, 72, 74Paradox: 9, 22, 59, 62, 92

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SC:

Overall Changes

The 11th edition has 156 Sentence Correction problems (including 18 Diagnostic



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%).

Topic DistributionClassifying 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.

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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, butModifiers replaces Comparisons in the #2 position.






Light colors represent repeated questions.

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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.

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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 factthat (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 almostcertainly 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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All New Sentence Correction Problems

1, 3, 6, 8, 11, 13, 16, 18, 21, 23, 26, 28, 31, 33, 36, 38, 41, 43, 46, 48, 51, 53, 56, 58, 61,

63, 66, 68, 71, 73, 76, 78, 81, 83, 86, 88, 91, 93, 96, 98, 101, 103, 106, 108, 111, 113,

116, 118, 121, 123, 126, 128, 131, 133, 136, 138, 140

New Sentence Correction Problems by Category

Again, most Sentence Correction problems test your knowledge of more than one topic

or issue. The following classifications are based on the primary topic tested in the

problem.

Meaning/Concision: 8, 16, 21, 31, 93, 98

Subject-Verb Agreement: 13, 66, 68, 78, 133, 140

Parallelism: 6, 11, 26, 28, 36, 46, 53, 56, 81, 83, 88

Pronouns: 1, 23, 91, 101, 113

Modifiers: 18, 38, 48, 58, 61, 63, 71, 103, 111, 121, 126

Verb Tense/Voice/Mood: 3, 41, 86, 128

Comparisons: 43, 76, 108, 123, 131, 136, 138

Idioms: 33, 51, 73, 96, 106, 118

Odds & Ends: 116

O.G 12 VS. O.G 11

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