The OG13 has flaws, as did its predecessors. Why five stars, then? Because, hands down, this latest incarnation of the OG is still the one book to get, if you can only get one book to prepare for the GMAT with. There's simply no better all-in-one source of retired GMAT problems.
Could the explanations be better? Sure.
Could the GMAT folks have replaced more than just 1 in 6 problems from the OG12? Absolutely.
Why did some repeated problems illogically jump the line backwards or forwards, given that both OG12 and OG13 are supposed to be in order of difficulty? Who knows.
All that said, the OG is still THE primary religious text of the GMAT. Everything else--including all that we write in print or in byte--is commentary.
The 158 new problems in OG13 all exude that sweet, ineffable air of GMAT-ness. Even if you're taking the GMAT before the changeover (on June 5), in your shoes I'd buy this book for those new problems alone. In the grand scheme, I'd consider that a good investment.
If you're taking the GMAT on June 5 or after, you also need to prepare for the new Integrated Reasoning section. This book gives you access to 50 IR practice problems on a separate site online. Another reason to purchase.
Now, on to the analysis...
Analysis of the 13th Edition Official Guide
(This analysis was originally published with additional content at [...])
The 13th Edition of the Official Guide for GMAT Review has finally been released publicly. Here at Manhattan GMAT, we've done an initial analysis of the OG13 book.
1. Not Radically Different
OG13 contains 907 practice problems for the "main" part of the GMAT (Quant & Verbal). Of those 907 problems, only 17% are new. Since you know your fraction equivalents, we don't have to tell you that 17% is about 1 out of 6.
Out of 907 problems, 749 are repeats (yes, that's 5 out of 6). If you already have the 12th Edition, a good way to look at the 13th Edition is as a source of 158 great new practice problems. We've listed them by number at the end of this post.
Much of the book is unchanged from the 12th Edition:
- For repeated problems, the explanations are identical, except for a few extremely minor edits (e.g., fixing an error in numbers chosen to test Statement 1 in DS #135).
- Various sections, such as the Diagnostic Exam (all 100 problems), Math Review, Test-Taking Strategies and Directions, are unchanged.
- Each of the 5 major types (PS, DS, RC, CR, and SC) has the same number of problems as before: 254 PS, 198 DS, 156 RC, 141 CR, and 158 SC.
- Excluding the Diagnostic Exam, practice questions are organized by difficulty, according to the GMAC--just as they are in the 12th edition--but with an asterisk we'll explain below.
We've done all the new problems, and they're just what you'd expect--good, clever GMAT problems. Each one has its own unique flavor, but they're all from the same big box of cookies. Given that only 1 in 6 are new, we don't ascribe too much meaning to the unavoidable micro-shifts in topical balance.
Do not over-interpret changes from OG12 to OG13! Some variation is to be expected. Nothing suggests a shift in how you should prepare for the exam.
2. Transition If And When You're Comfortable
If you've been getting ready with the 12th Edition, treat the 13th Edition as a source of additional practice. But you do not need to switch, especially if your exam is before June 5, when the new GMAT arrives.
If you're taking an "old" GMAT, consider mining the 13th Edition for a few new problems. But your time may be better spent reviewing practice problems you've already encountered. Or you might just do online practice with GMATPrep, GMATFocus, or practice exams such as ours.
3. Integrated Reasoning is Integrated
If you are taking the "new" GMAT (on or after June 5), the OG13 has some relevant goodies for you: a short introduction to IR, plus access to 50 brand-new practice problems online. Even though the IR section won't count for much in the admissions process, you don't want to face it completely cold. Running through these 50 problems will help warm you up.
In fact, you might catch fire and start freaking out about IR. If that happens, go dunk your head in water. IR is not that important. You just want to give it a decent shot. Save your strength for the main event of the GMAT.
4. Order Oddities
Both OG12 and OG13 claim to be laid out in order of difficulty (except for the 100 Diagnostics). Since all the problems are retired from the real exam, that order should never change--so you'd expect repeated problems to maintain their relative positions in the hierarchy.
Weirdly, though, 25 repeated problems have jumped out of position. Here are the rebels:
13th Ed.|12th Ed.|Change
20 203 -183
25 200 -175
31 64 -33
55 196 -141
65 28 37
67 201 -134
95 106 -11
109 69 40
126 228 -102
132 93 39
181 202 -21
13th Ed.|12th Ed.|Change
4 47 -43
38 134 -96
53 165 -112
58 171 -113
67 30 37
78 137 -59
81 58 23
119 173 -54
120 147 -27
125 107 18
128 157 -29
135 128 7
143 161 -18
166 132 34
While we've understood and agreed with the OG difficulty ordering in broad strokes, we've always wondered about some of the specific rankings. Is Marcia's Bucket (DS #174) truly the hardest DS problem on the planet, three editions running--11th, 12th, and 13th? That one has always bewildered us.
The reshuffle is generally in the right direction, if we were doing the ranking of those 25 problems. For instance, we think that PS #69 in the 12th is harder than PS #196 in the 12th, not conceptually but in actual execution. Old #69 is tricky! Now the new numbering (#109 and #55, respectively, in OG13) reflects that opinion.
However, the mystery is why this reshuffling is happening at all. If the problems were in relative order of difficulty in one edition, any repeats should stay in that order till the end of time--since the problems are most definitely retired!
This weird reordering happened before on a smaller scale, when the supplemental Review OGs transitioned from 1st to 2nd Editions. One problem in each slipped out of position. That level of change could be chalked up to clerical error or to random genetic mutation caused by a stray cosmic ray or what have you.
However, with 25 problems on the quant side (and none on the verbal side) acting illogically, we can only guess at something larger. It should be straightforward for the GMAT to measure difficulty--it's a basic parameter for each question, a single number developed during the problem's experimental stage and then frozen. Perhaps, for a whole batch of questions, these parameters were recorded in a systematically erroneous way, and now GMAC is fixing the problem. Maybe the way GMAC measures difficulty has some quirks to it, and under an update to the algorithm these problems would somehow get a different ranking.
Regardless, we don't think there's anything nefarious to all this--there's no reason that GMAC would deliberately mess with our heads. After all, the 10th Edition of the OG, for those of us who go back that far, was comfortably chaotic. It had no order whatsoever. The 11th Edition was the first one that the GMAT folks put in order of difficulty--and we all welcomed that change. It made studying so much more productive to know how hard a problem was to the GMAT, if only in relative terms.
As we find out more on this matter, we'll let you all know.
5. Stay Tuned
More generally, as we dig further into OG13, we'll keep you posted on any juicy discoveries. Again, we don't want to squint too hard at the tea leaves. We'll start seeing things that aren't really there: "Is there one more or one less Probability problem, and what signal is the GMAT sending...?" That road leads to madness. This OG is pretty much the same as the last one, just with some new good problems in it.
6. New Problems
And now, what you've been waiting for... here are the new problem lists, all by number in the OG13. We're moving a couple of topics around ourselves, so these breakouts reflect the upcoming topical alignments.
Problem Solving: 12, 13, 14, 15, 37, 49, 56, 57, 60, 61, 69, 71, 75, 77, 78, 79, 80, 81, 91, 92, 108, 110, 112, 113, 114, 117, 118, 119, 127, 128, 129, 137, 158, 163, 166, 170, 177, 178, 182, 183, 196, 198, 199, 218, 229
PS Fractions, Decimals, & Percents: 15, 56, 57, 71, 80, 108, 113, 114, 163, 170, 177, 182, 198, 218
- Digits & Decimals: 163, 170, 218
- Fractions: 15, 80, 108
- Percents: 57, 71, 114, 177, 182, 198
- Ratios: 56, 113
PS Algebra: 14, 37, 117, 129, 196, 199
- Linear Equations: 14
- Exponents & Roots: 196
- Quadratic Equations: 37, 117, 199
- Formulas: 129
PS Word Problems: 12, 49, 60, 79, 81, 91, 112, 119, 137, 158, 178, 183
- Algebraic Translations: 60, 137
- Rates & Work: 49, 79, 81
- Statistics: 12, 91, 112, 119, 183
- Consecutive Integers: 158
- Overlapping Sets: 178
PS Geometry: 13, 61, 69, 75, 78, 92, 166
- Polygons: 13, 78, 166
- Triangles & Diagonals: 75, 92
- Circles & Cylinders: 69
- Coordinate Plane: 61
PS Number Properties: 77, 110, 118, 127, 128, 229
- Divisibility: 77, 110, 118, 127
- Positives & Negatives: 229
- Combinatorics: 128
Data Sufficiency: 11, 15, 18, 20, 22, 23, 24, 25, 29, 32, 33, 34, 37, 39, 41, 42, 52, 57, 65, 70, 74, 75, 79, 80, 83, 85, 92, 96, 97, 99, 102, 109, 123, 131, 133, 141
DS Fractions, Decimals, & Percents: 23, 25, 29, 75, 80, 92, 131, 133
- Digits & Decimals: 75, 80, 133
- Fractions: 29, 92, 131
- Percents: 25
- Ratios: 23
DS Algebra: 15, 24, 33, 41, 52, 85, 96, 99
- Exponents & Roots: 15, 41
- Quadratic Equations: 99
- Formulas: 24, 96
- Inequalities: 33, 52, 85
DS Word Problems: 18, 20, 22, 34, 37, 57, 65, 70, 109, 123, 141
- Algebraic Translations: 57, 65, 141
- Rates & Work: 22
- Statistics: 20, 37, 70, 109, 123
- Consecutive Integers: 18
- Overlapping Sets: 34
DS Geometry: 11, 42, 74, 79, 102
- Polygons: 42
- Triangles & Diagonals: 79
- Circles & Cylinders: 102
- Coordinate Plane: 11, 74
DS Number Properties: 32, 39, 83, 97
- Divisibility & Primes: 83
- Positives & Negatives: 97
- Odds & Evens: 32
- Probability: 39
Reading Comprehension: 1, 2, 3, 4; 11, 12, 13; 14, 15, 16, 17; 37, 38, 39, 40, 41; 52, 53, 54, 55; 84, 85, 86; 111, 112, 113, 114 (passages separated by semicolons)
7 new passages
- Length: 2 long, 5 short (3 of the shorts are just 1 big paragraph, though!)
- Themes: 2 biological science, 2 business, 2 social science, and 1 physical science
7 General questions (4 Main Idea, 3 Structure) - roughly 1 per new passage
20 Specific questions (8 Detail, 12 Inference) - roughly 3 per new passage
Since you'd never do all the questions of 1 type at once (you always do RC by passage), there's little point in breaking them out by number.
Critical Reasoning: 1, 3, 6, 8, 9, 11, 12, 17, 19, 22, 29, 33, 39, 49, 59, 65, 69, 74, 81, 86, 94, 100, 106, 114, 124
- Assumption: 106
- Evaluate the Argument: 114, 124
- Flaw: 8, 100
- Strengthen: 1, 11, 19, 29
- Explain the Discrepancy: 3, 6, 9, 17, 22, 49, 86, 94
- Complete the Argument: 12, 33, 39, 59, 65, 69, 74, 81
Sentence Correction: 1, 2, 4, 7, 9, 15, 19, 26, 35, 38, 40, 48, 56, 65, 68, 71, 74, 79, 87, 97, 107, 111, 114, 132, 138
- Subject-Verb Agreement: 7
- Parallelism: 4, 15, 38, 56, 74, 79, 87, 138
- Pronouns: 111, 114
- Modifiers: 1, 19, 35, 48, 65, 68, 132
- Verbs: 40, 71
- Comparisons: 9, 107
- Connecting Punctuation: 2, 26, 97
I started GMAT Club - online MBA community; my GMAT score is 750 (49, 42), and here are my thoughts about this book:
~~~ Strengths ~~~
1. 907 real GMAT questions retired from past tests (158 new questions in this edition). The total has not changed
2. Practice questions are organized by level of difficulty
3. Practice questions follow actual GMAT test patterns (it's great to have one's ear trained, esp. in verbal)
4. Contains a 100-question diagnostic test
5. Overview of the Integrated Reasoning section (50 questions)
~~~ Weaknesses ~~~
1. Does not include any test-taking strategies
2. Though it has a few short review sections for each area, they are weak and very unfriendly
3. Questions are predominantly low to medium in difficulty which is often not representative of questions one encounters on the test
4. There is an 83% overlap with the previous edition (12th edition). Compared to 66% overlap between OG 12 and OG 11
~~~ Contents (number of questions per section)~~~
1. Diagnostic Test - 100 questions
2. Problem Solving - 230 questions
3. Data Sufficiency - 174 questions
4. Reading Comprehension - 139 questions
5. Critical Reasoning - 124 questions
6. Sentence Correction - 140 questions
7. Integrated Reasoning - 50 questions (not included in the 907 count)
~~~ What Questions Are New? ~~~
* Problem Solving
12, 13, 14, 15, 37, 49, 56, 57, 60, 61, 69, 71, 75, 77, 78, 79, 80, 81, 91, 92, 108, 110, 112, 113, 114, 117, 118, 119, 127, 128, 129, 137, 158, 163, 166, 170, 177, 178, 182, 183, 196, 198, 199, 218, 229.
* Data Sufficiency
11, 15, 18, 20, 23, 24, 25, 29, 32, 33, 34, 37, 39, 41, 42, 52, 57, 65, 70, 74, 75, 79, 80, 83, 85, 92, 96, 97, 99, 102, 109, 123, 131, 133, 141.
* Critical Reasoning
1, 3, 6, 8, 9, 11, 12, 17, 19, 22, 29, 33, 39, 49, 59, 65, 69, 74, 81, 86, 94, 100, 106, 114, 124
* Reading Comprehension
Passage 1 (Questions 1-4), Passages 4&5 (Questions 11-17), Passage 9 (Questions 37-41), Passage 12 (Questions 52-55), Passage 17 (Questions 84-86), Passage 22 (Questions 111-114)
* Sentence Correction
1, 2, 4, 7, 9, 15, 19, 26, 35, 38, 40, 48, 56, 65, 68, 71, 74, 79, 87, 97, 107, 111, 114, 132, 138
*** Why is this book valuable/must-have?
The Official Guide is published by the creators of the GMAT and therefore it is the only source of actual GMAT questions representative of what you will see on the test.
*** Why is the book not sufficient by itself?
This Guide contains only questions and lacks insightful information about the test, a math/verbal concept review section, or any test-taking strategies. To get up to speed, you will need to get a study guide such as Kaplan Premier Program or Manhattan GMAT's 8 guides.
*** How should this book be used?
This book should NOT be used as a study-guide. It is a collection of questions - think of it as a way to practice your test-taking strategies but not a way to learn them.
*** What if I own a previous edition of this book?
If you have the 12th edition, the only differences between the two are 157 new questions and IR section overview (there is an online companion for IR). Most test-takers agree that 157 new questions is not a compelling enough reason to own both editions, as the 12th edition offers enough practice. However, if you are taking the test after June 5th, you do want this book for the IR section.
*** What is a recommended study plan using The Official Guide?
There are a number of approaches that work - here is one that most find reasonable:
Step 1: Buy a GMAT Guide from Kaplan (will take about a month to cover it). Get familiar with the test and brush up on fundamentals (math and grammar); also these books will give you a good base for test-taking and timing strategies. This is enough for a 600-level score. I would also recommend to everyone to get GMAT Roadmap by MGMAT. It is a great book packed with common sense and student wisdom on how to best approach the GMAT.
Step 2: Take a GMAT Prep (2 free tests downloadable from MBA.com) - but don't waste these; these are free but very valuable tests. Take 1 after you go through the Guidebooks and save the second one for later. These tests will be representative of your GMAT score (plus/minus 40 points).
Step 3: (Optional - if you want a 650+ score) Get a specialized Math and/or Verbal workbook from Kaplan, the 8-book set form Manhattan GMAT, or Veritas Prep Guides and do a deep dive into the fundamentals - this is what will help you crack the test - solid knowledge of Math and Grammar. You should also look into the MGMAT Foundations of GMAT Verbal and MGMAT Foundations of GMAT Math.
Step 4: By now you should have a good understanding of question patterns, strategies, and timing. Start working on the Official Guide and honing your skills - this is especially important for Critical Reasoning questions that have certain unspoken patterns and rules that only the Official Guide offers - work through the questions to train your ear. Keep in mind that these questions are on the easier side if you are aiming for 650+.
*** What are some of the good study suggestions?
- Start with a practice test (diagnostic test)
- You need quality time. It is really the quality time (morning for some and evening for others) that provides the most retention and results
- Don't skip or move past a section until you're able to solve 90% of the questions correctly (timed of course). That is if you want 700+
- Never solve questions without timing yourself (unless it is quick drills)
- Don't jump into the hardest areas first - build confidence instead with what you know and can demonstrate progress at
- Start every new day with the review of what you have learned the day before
- Make notes for everything you cover - it helps tremendously to retain what you have learned even though you may never read them. The process of making notes is a very helpful learning experience. If nothing else works - use it
- Finally, your practice tests are a usually a very good indicator of your performance. If you are getting 600 on your practice tests, there is about a 2% chance that you will get a 700 score. Do not be surprised when you score on real test a 600
Any questions, please ask away - I reply to comments!
Good luck on your test,
BB, GMAT 750 (49, 42)
The Official Guide book for the GMAT exam is the essential standard book you need for the GMAT exam. At over 800 pages (839 pages!) it's plenty to work with - plenty of opportunities to catch your mistakes in practice so you don't make the same ones on the actual exam.
In the past 3 years, everyone's been using OG12 (12th edition) to study for their GMATs. Certainly, every few years there's a few updates. This 13th edition update is bigger for a variety reasons.
There's a new section called integrated reasoning (on-screen calculator, 12 questions with multiple subquestions, 30 min, NO partial credit), and a small slight change in mix of questions for SC and for CR.
There is no where else to get practice questions for Integrated Reasoning (at least for the first few months) without getting them from the Official Guide or the GMATPrep 2.0 software. (You can get the IR separately, see link below)
The questions are as official as they can be.
83% of the OG13 questions are the same as the OG12 questions. They basically removed 17% of the old questions and replaced them with new questions - so you're not getting *more* questions - you're simply getting questions that are most reflective of the latest version of the exam.
There are 907 questions - 158 of them are NEW, which is 17% of the questions. There is an additional 50 Integrated Reasoning questions but these questions are not in the book. You have to access them with a username/password and Access Code on a companion website to the book -
[can't provide URL due to filtering but gwhizmobile is the domain name and GMAC is the directory]
Now, onto the sections:
Integrated Reasoning -
THIS SECTION IS NOT IN THE BOOK - it's an online component with 50 questions, which you can access with an account. The book has 11 pages dedicated to introducing you to the Integrated Reasoning section - it introduces the 4 types of questions which takes up the bulk of it in the book. But the practice questions are online. Here are the question types:
1) Multi-source Reasoning
2) Table Analysis
3) Graphics Interpretation
4) Two Part Analysis
Once on the online site, you'll signup with your access code. All future logins will use your email address. The IR section DOES allow you to use an on-screen calculator - so get used to using it! - while the other normal sections do not.
Integrated Reasoning Questions - wow, some of them get really tricky because for each question, there are usually 3 sub-questions (sometimes more) and you're going to want to get ALL of them correct to get credit for that question. I went through a bunch and here are my observations:
1) Some really tricky questions with booby traps - complex wording you have to read through and understand
2) Dives into many details. Contrary to RC which is about getting the big picture main idea then occasionally diving into details, IR is about DETAILS.
3) Topics are much more modern business - finally. The IR questions finally stray away from historical humanities and focus on things like internet businesses, print-to-online media, IPO, consulting tables and charts. So, if you were complaining about the GMAT not being relevant to business before - you can't complain anymore. Even if the topics here are more relevant, they can STILL be tricky. I repeat, tricky!
4) Multiple steps to get to the right answer: You're going to need to jot down some notes on a piece of paper showing your calculation results. Once written down, you can compare the figures and figure out the right answer.
5) On-screen calculator - Yes, this section permits use of a calculator but it is an on-screen calculator. I did in fact find myself playing around using the MR, MS and M+ buttons - I had never really learned how to use them in school but yes, they can be helpful for the questions involving multiple calculations - which I did see in many of the IR questions.
6) Graphic charts are very similar to what you'll see in business consulting. Bar charts, pie charts, and even XYZ Bubble charts. I'm hoping to see a waterfall chart one day...
7) Colors! Unlike the old exam which is completely black and white, the IR section includes some COLORS in its graphs and charts. So yes, more in tune with the modern world - you might see a scatterplot of points in red / blue / black or green colors!
If you are only interested in the IR section you can purchase it here for $10 (cheaper than ~$25 for the book):
[ can't provide URL but it's in the MBA dot com store with product ID 5032 ]
Sentence Correction (158)- Similar to the way it was before, SC is basically a sentence with an underlined portion. Your job is to figure out if that underlined portion of the sentence is the optimal way of writing - or whether one of the remaining 4 answer choices offers a better, more clearer way of communicating that same idea. GMAC folks have been slowly pushing in more questions that are related to meaning and fewer questions related to idioms.
Critical Reasoning (141) - This section is more or less the same with the exception of a greater emphasis on questions that ask you to fill in the blank and complete the logical argument.
Reading Comprehension (156) - as with almost all tests, there's a reading component. This is a classic component of many standardized tests. Boring passages, boring questions. The challenge here is getting yourself excited about these boring passages so you can actually answer them and make sense of the author's argument!
Problem Solving (254) - There's roughly 45 new questions in this version here. For the most part, the difficulty varies. I'd say the number of easy questions here are quite a bit. Because of the computer adaptive nature of the test, if you aim for the upper 600s and lower 700s, most likely you won't be asked some of the super easy questions here.
Data Sufficiency (198) - So there's 36 new added questions in this section. The wording here seems a bit more tricky and difficult. Of course the essential thought process approach we teach to attack this infamous section of the GMAT is the same so as long as you come in with the correct attack strategy, you'll be fine.
1) The Official Guide provides the highest quality of questions to use for your preparation needs. After all, they do include actual exam questions used in the past - usually referred to as "retired questions" - so definitely good to practice with these kinds of questions.
2) Is OG13 worth it? If you want some extra practice and also get online access to the integrated reasoning question bank - it's worth it for the price. Every serious MBA student should at least take a peek before the exam.
3) Having said that, keep in mind OG is for practice purposes. It does not teach you how to think. And certainly don't expect their explanations to guide you to the path of enlightenment. There's a reason why everybody buys the OG but still not everyone gets a top score. Certainly the book is necessary - but by no means an automatic ticket to the top MBA club.
Let's apply a fun logic / critical reasoning game here.
Statement: Buying OG13 will get me a 700+ score.
There is a flaw in this statement! Getting access to official exam questions does not imply that you can answer that type of question when presented in another form. Nor does buying the book indicate that you can answer it under time-pressured environments. OG provides practice questions - not exam strategy, which is its only weakness. I'd say exam strategy is well over 50% of the exam.
That said, OG is the standard. There really is no reason to rate this book 3 star or 4 star - it's the standard for this exam so it gets a 5 star. GMAC is not here to train how your brain thinks - it's here to give you sample questions from past exams. And that's exactly what it does.
I bought this book about three months prior to taking my GMAT's. I did no other preparations or studying outside of this book and I was able to get a 750 on my GMAT's.
I did about 40 verbal questions and 40 quantitative questions every time I sat down to study (comparable to the number of questions on the actual GMAT's). Studying about 2-3 times a week for about 3 hours each time, I felt fully prepared for the GMAT's. This is a great book that will help you prepare for the exam and this is a must-have for anyone looking to take the exam in the future. The hardest thing for me was the pacing though. While studying for the exam, I highly recommend timing yourself (75 mins for ~40 questions).