Jun 24 2017

2018 GMAT Official Guide Bundle – Detailed Analysis

2018 GMAT Official Guide BundleGMAT Genius has thoroughly analyzed the 2018 GMAT Official Guide Bundle and we want to share our insights with you. Feel free to read our detailed analysis of the 2018 GMAT Official Guide Bundle or skip down to our conclusions. Wishing you tremendous success with the GMAT!

Overview of 2018 GMAT Official Guide Bundle

The Official Guides for GMAT Review contain retired real GMAT questions, and are an essential component of your GMAT preparations. The GMAC places questions in order of increasing difficulty, based on its assessment of difficulty. The three books in this bundle have no overlap in practice questions.

Our objective below is to provide a combined analysis of each question type (e.g. combine data for all Problem Solving questions across all books). You will find a list of new questions and detailed question categorization in our prior posts on the individual books:
The 2018 Official Guide for GMAT Review
The 2018 Official Guide for GMAT Quantitative Review
The 2018 Official Guide for GMAT Verbal Review

The 2018 GMAT Official Guide Bundle contains 220 new questions out of the 1,566 total questions (including Integrated Reasoning). Excluding the 100 questions in the Diagnostic Exam section of the main book, the new questions represent 15% new content. These are new questions that we have not encountered before; they are not questions recycled from older GMAC resources.

Problem Solving

The 2018 GMAT Official Guide Bundle contains a total of 430 Problem Solving questions. The GMAC classifies question difficulty into three categories as follows:

Difficulty Number Percent Change
Easy 185 43% +18
Medium 102 24% (5)
Hard 143 33% (13)

There are 61 new Problem Solving questions, with difficulty of Easy / Medium / Hard as follows: 37 / 12 / 12. This is in lieu of 61 questions from the 2017 edition that have been removed, with difficulty of Easy / Medium / Hard as follows: 19 / 17 / 25.

GMAT Genius classifies question difficulty into five categories. Our assessment of Problem Solving skews noticeably less difficult / more towards the center and is only 72.1% correlated with the GMAC’s assessment, demonstrating tremendous subjectivity involved in assessing question difficulty. Here’s our breakdown:

Difficulty Number Percent Change
Super Easy 44 10% +2
Easy 125 29% +2
Medium 166 39% (6)
Hard 68 16% (1)
Very Hard 27 6% +3

Although math questions often entail multiple math concepts, GMAT Genius classifies questions based on our assessment of the primary math concept. We break down the 430 Problem Solving questions as follows:

Type Concept Number Percent Change
Arithmetic Basic 26 6% +5
Arithmetic Absolute Value 7 1.6%
Arithmetic Divisibility/Factors/Mult. 24 5.6% (1)
Arithmetic Exponents & Roots 26 6% (5)
Arithmetic Fractions & Ratios 50 11.6% (1)
Arithmetic Percents 32 7.4% (3)
Arithmetic Pos/Neg & Odd/Even 2 0.5% (2)
Arithmetic Primes 4 0.9%
Algebra Inequalities 9 2.1% +1
Algebra Linear Equations 23 5.3% +1
Algebra Quadratics 18 4.2% +2
Algebra Simultaneous Equations 13 3%
Algebra Variables in Answers 13 3% +2
Geometry Circles 8 1.9% (1)
Geometry Coordinate 12 2.8% (1)
Geometry Rectangles 12 2.8%
Geometry Triangles 12 2.8% +2
Geometry Other 11 2.6%
Statistics Averages 32 7.4%
Statistics Other 10 2.3% +1
Word Problems Combinatorics 11 2.6%
Word Problems Functions & Sequences 22 5.1% (1)
Word Problems Groups/Sets 10 2.3% +1
Word Problems Probability 9 2.1% (1)
Word Problems Revenue/Profit/Interest 14 3.3% +2
Word Problems Rate & Work 20 4.7% (1)

Data Sufficiency

The 2018 GMAT Official Guide Bundle contains a total of 322 Data Sufficiency questions. The GMAC classifies question difficulty into three categories as follows:

Difficulty Number Percent Change
Easy 85 26% +9
Medium 90 28% +8
Hard 147 46% (17)

There are 45 new Data Sufficiency questions, with difficulty of Easy / Medium / Hard as follows: 13 / 16 / 16. This is in lieu of 45 questions from the 2017 edition that have been removed, with difficulty of Easy / Medium / Hard as follows: 4 / 8 / 33.

GMAT Genius classifies question difficulty into five categories. Our assessment skews significantly easier and is only 61.0% correlated with the GMAC’s assessment. Here’s our breakdown:

Difficulty Number Percent Change
Super Easy 21 7% +3
Easy 83 26% +5
Medium 144 45% (2)
Hard 62 19% (4)
Very Hard 12 4% (2)

Although many math questions entail multiple math concepts, GMAT Genius classifies questions based on our assessment of the primary math concept. We break down the 322 Data Sufficiency questions as follows:

Type Concept Number Percent Change
Arithmetic Basic 20 6.2% +5
Arithmetic Absolute Value 1 0.3%
Arithmetic Divisibility/Factors/Mult. 17 5.3% +3
Arithmetic Exponents & Roots 26 8.1% (1)
Arithmetic Fractions & Ratios 19 5.9% (2)
Arithmetic Percents 21 6.5% (1)
Arithmetic Pos/Neg & Odd/Even 13 4% (1)
Arithmetic Primes 4 1.2% +1
Algebra Inequalities 26 8.1% +6
Algebra Linear Equations 14 4.3% +1
Algebra Quadratics 10 3.1% +1
Algebra Simultaneous Equations 18 5.6% (6)
Geometry Circles 11 3.4% +1
Geometry Coordinate 11 3.4%
Geometry Rectangles 7 2.2%
Geometry Triangles 13 4%
Geometry Other 7 2.2% (1)
Statistics Averages 20 6.2%
Statistics Other 15 4.7% (1)
Word Problems Functions & Sequences 11 3.4% (1)
Word Problems Groups/Sets 15 4.7% +1
Word Problems Probability 4 1.2% (1)
Word Problems Revenue/Profit/Interest 8 2.5% (2)
Word Problems Rate & Work 11 3.4% (2)

Sentence Correction

The 2018 GMAT Official Guide Bundle contains a total of 158 Sentence Correction questions. The GMAC classifies question difficulty into three categories as follows:

Difficulty Number Percent Change
Easy 71 26% +5
Medium 75 28% (26)
Hard 125 46% +21

There are 38 new Sentence Correction questions, with difficulty of Easy / Medium / Hard as follows: 12 / 4 / 22. This is in lieu of 38 questions from the 2017 edition that have been removed, with difficulty of Easy / Medium / Hard as follows: 7 / 13 / 18. The GMAC has assigned a different difficulty rating to a total of 17 Sentence Correction questions, upgrading these 17 from Medium to Hard difficulty.

GMAT Genius classifies question difficulty into five categories. Our assessment skews noticeably easier and is only 59.9% correlated with the GMAC’s assessment, clearly demonstrating the subjectivity involved in assessing question difficulty. Here’s our breakdown:

Difficulty Number Percent Change
Super Easy 7 3% (1)
Easy 77 28% +3
Medium 110 41% (3)
Hard 65 24% +3
Very Hard 12 4% (2)

Although Sentence Correction questions typically entail multiple grammar concepts (as described on our website), GMAT Genius classifies questions based on our assessment of the primary tested concept. We classify the 271 Sentence Correction questions as follows:

Concept Number Percent Change
Verb Agreement 26 9.6% +1
Verb Tense 35 12.9% (1)
Pronoun Ambiguity 21 7.7% +2
Pronoun Agreement 15 5.5%
Parallel Construction 78 28.8% (6)
Misplaced Modifiers 33 12.2% +1
Idioms 19 7% +2
Comparison & Quantity 18 6.6% (1)
Expression & Meaning 26 9.6% +2

Critical Reasoning

The 2018 GMAT Official Guide Bundle contains a total of 224 Critical Reasoning questions. The GMAC classifies question difficulty into three categories as follows:

Difficulty Number Percent Change
Easy 72 32% (3)
Medium 71 32%
Hard 81 36% +3

There are 31 new Critical Reasoning questions, with difficulty of Easy / Medium / Hard as follows: 7 / 7 / 17. This is in lieu of 31 questions from the 2017 edition that have been removed, with difficulty of Easy / Medium / Hard as follows: 10 / 8 / 13. The GMAC has assigned a different difficulty rating to one Critical Reasoning question.

GMAT Genius classifies question difficulty into five categories. Our assessment skews slightly more towards the center, yet is only 72.3% correlated with the GMAC’s assessment, clearly indicating subjectivity involved in assessing question difficulty. Here’s our breakdown:

Difficulty Number Percent Change
Super Easy 1 0%
Easy 61 27% (8)
Medium 89 40% +1
Hard 52 23% +5
Very Hard 21 9% +2

We have grouped the questions based on the question type categorization that GMAT Genius uses for Critical Reasoning (as described on our website). We break down the 224 Critical Reasoning questions as follows:

Concept Number Percent Change
Weaken 49 21.9% +3
Strengthen 43 19.2% (3)
Assumption 22 9.8% +2
Reasoning 7 3.1% (1)
Conclusion 16 7.1%
Explain 23 10.3% (1)
Evaluate 22 9.8%
Boldface 13 5.8%
Complete the Passage 29 12.9%

Reading Comprehension

The 2018 GMAT Official Guide Bundle contains a total of 261 Reading Comprehension questions across 52 passages. The GMAC classifies question difficulty into three categories as follows:

Difficulty Number Percent Change
Easy 89 34% +10
Medium 101 39% (9)
Hard 71 27% (1)

There are 37 new Reading Comprehension questions, with difficulty of Easy / Medium / Hard as follows: 13 / 18 / 6. This is in lieu of 37 questions from the 2017 edition that have been removed, with difficulty of Easy / Medium / Hard as follows: 3 / 23 / 11. The GMAC has assigned a different difficulty rating to a total of 4 Reading Comprehension questions.

GMAT Genius classifies question difficulty into five categories. Whereas the GMAC assigns the same difficulty to all questions for a given passage (except in the Diagnostic Exam section), GMAT Genius assesses the difficulty of each question individually. Our assessment skews very slightly harder, but is only 58.8% correlated with the GMAC’s assessment, in large part due to different difficulty assessment methodologies. Here’s our breakdown:

Difficulty Number Percent Change
Super Easy 13 5% +1
Easy 65 25% +3
Medium 103 39% (3)
Hard 62 24%
Very Hard 18 7% (1)

We have grouped the questions based on the question type categorization that GMAT Genius uses for Reading Comprehension (as described on our website). We break down the 261 Reading Comprehension questions as follows:

Concept Number Percent Change
Primary Purpose 36 13.8% (2)
Author’s Tone 16 6.1%
Organization 8 3.1% +1
Function 35 13.4% +2
Specific Reference 62 23.8% (1)
Inference 87 33.3% (2)
Critical Reasoning 17 6.5% +2

Integrated Reasoning

The main Official Guide (part of this bundle) includes online access to 58 Integrated Reasoning practice questions. The IR set includes 8 new questions that we have not seen before, plus all 50 questions from the prior 2017 edition. The 58 questions consist of the following four types:
Multi-Source Reasoning – 21 (3 new)
Table Analysis – 7 (1 new)
Graphics Interpretation – 12 (2 new)
Two-Part Analysis – 18 (2 new)

The GMAC classifies question difficulty into three categories of Easy / Medium / Hard as follows:
Multi-Source Reasoning – 6 / 7 / 8
Table Analysis – 3 / 1 / 3
Graphics Interpretation – 4 / 3 / 5
Two-Part Analysis – 5 / 7 / 6
Total – 18 / 18 / 22

Out of the 50 questions that carry over from the 2017 edition, the GMAC has reclassified the difficulty of 33 questions. For IR, GMAT Genius classifies question difficulty into the same three categories. Except for Two-Part Analysis, our assessment skews significantly easier, and contains notable differences from the GMAC. Our difficulty assessment is only 8.1% correlated with the GMAC’s assessment, clearly showing that there is tremendous subjectivity involved in assessing question difficulty. Here’s our breakdown of Easy / Medium / Hard:
Multi-Source Reasoning – 9 / 11 / 1
Table Analysis – 3 / 4 / 0
Graphics Interpretation – 3 / 7 / 2
Two-Part Analysis – 2 / 10 / 6
Total – 17 / 32 / 9

Online Interface

2018 GMAT Official Guide Bundle OnlineEach Official Guide book includes an access code (see inside front covers) that provides 12-month usage of an online version of the book. The online practice interface is the same as it was previously, except that the onerous limit of 10 saved sessions has been increased to 25 saved sessions in Exam Mode plus 25 saved sessions in Practice Mode (which you should not use, as mentioned below). The 100 questions from the Diagnostic Test chapter of the main Official Guide are available in a separate tab that works with Exam Mode functionality.

Since the GMAT is a computer-based test, we believe that it is advisable to work though the questions online. We strongly suggest that you use Exam Mode rather than Practice Mode, since we recommend that students practice using timed question sets that replicate test day conditions. The functionality of the online platform is good overall. You can choose practice sets by question type and difficulty level. Every question lists the corresponding book question number for easy cross-referencing.

Other Notes

The Official Guides are for practicing with real GMAT questions, not for learning the underlying concepts. The 40-page Math Review section provides a very high-level overview of the math concepts tested on the GMAT. This math review will be highly inadequate except perhaps for the most advanced math students. Similarly, the brief introductions to the concepts tested on the verbal section are highly inadequate. We recommend that you use additional study materials to learn the math and verbal concepts.

Although all questions include answer explanations, many GMAT test takers are far from satisfied with these explanations. Math explanations can be brief and hard-to-understand for non-advanced students, and are sometimes convoluted or inefficient. Most GMAT test takers consider the Sentence Correction explanations quite cryptic. The Critical Reasoning and Reading Comprehension explanations, however, are reasonably good overall.

CONCLUSIONS

The Official Guide Bundle has three primary weaknesses, in our opinion:

  1. An insufficient amount of difficult practice questions, particularly based on GMAT Genius’ assessment of difficulty. We are especially dismayed to see the net loss of 30 Hard-difficulty Quant questions (13 Problem Solving and 17 Data Sufficiency) based on GMAC’s difficulty assessment compared to the 2017 edition.
  2. Math answer explanations that are too often either brief or convoluted and Sentence Correction explanations that are too cryptic.
  3. Contrary to what the back covers of the books claim, questions are not fully presented in order of progressive difficulty for Reading Comprehension in the main OG, for Data Sufficiency in the Quant OG, and for Critical Reasoning and Sentence Correction in the Verbal OG.

Despite these flaws, the 2018 GMAT Official Guide Bundle is an essential source of GMAT practice. We believe that every GMAT aspirant must use all three Official Guide books (this or the prior edition). If you already have the 2017 editions of the Official Guides, however, the replacement of 106 math questions and 106 verbal questions is not sufficient to make this edition worth purchasing.