标题: GMAT Official Guide 12th Edition [打印本页] 作者: BeyondY 时间: 2010-4-20 11:19 标题: GMAT Official Guide 12th Edition
GMAT Official Guide 12th Edition: An Overview
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Problem Solving
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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
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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.作者: BeyondY 时间: 2010-4-20 11:19
Data Sufficiency Has Grown
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.
Transition If And When You’re Comfortable
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.
The Official Guide, 12th Edition: Section By Section
Problem Solving
GMAT Official Guide 12th Edition: Sentence Correction
<< Back to 12th Edition Overview
Overall Changes
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.
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The proportion of new Sentence Correction problems (36%) is very nearly the same as the average for all problems (33%).作者: BeyondY 时间: 2010-4-20 11:21
Topic Distribution
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.
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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, but Modifiers replaces Comparisons in the #2 position.作者: BeyondY 时间: 2010-4-20 11:22
本帖最后由 BeyondY 于 2010-4-20 11:23 编辑
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 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.
Qualitative Observations
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).作者: BeyondY 时间: 2010-4-20 11:23
本帖最后由 BeyondY 于 2010-4-20 11:24 编辑
GMAT Official Guide 12th Edition: Critical Reasoning
<< Back to 12th Edition Overview
Overall Changes
Which Problems Changed?
For an exact list of differences between the 11th and 12th editions, download the Critical Reasoning Problem List.The 11th edition has 141 Critical Reasoning problems (including 17 Diagnostic problems). In the changeover to the 12th edition, 50 problems were removed, leaving 91 repeats (including all Diagnostics), and 50 problems were added, yielding 141 Critical Reasoning problems in the 12th edition – the same number as in the 11th edition.
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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 9 such 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.作者: BeyondY 时间: 2010-4-20 11:25
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 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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Qualitative Observations
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 it’s 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.作者: BeyondY 时间: 2010-4-20 11:26
GMAT Official Guide 12th Ed: Reading Comprehension
<< Back to 12th Edition Overview
Overall Changes
Which Problems Changed?
For an exact list of differences between the 11th and 12th editions, download the Reading Comprehension Problem List.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 113 repeated 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 passages—almost exactly the same as in the 11th edition.
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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%).作者: BeyondY 时间: 2010-4-20 11:26
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
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Two long passages (>300 words) were replaced by two short passages (<250 words). However, the overall proportion is essentially unchanged, with a rough balance between long and short.作者: BeyondY 时间: 2010-4-20 11:27
Passage Topic
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The distribution of passage topics hardly changed. There are 2 fewer biology passages, but we should expect some normal variation from edition to edition.作者: BeyondY 时间: 2010-4-20 11:29
本帖最后由 stream 于 2010-4-20 11:36 编辑
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.
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Seven passages at all levels of difficulty were removed, together with all their problems. 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.
[attach]5997[/attach]作者: BeyondY 时间: 2010-4-20 11:33
本帖最后由 stream 于 2010-4-20 11:37 编辑
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.
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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 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.
Qualitative Observations
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 and questions.
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.作者: BeyondY 时间: 2010-4-20 11:38
本帖最后由 stream 于 2010-4-20 11:44 编辑
Official Guide 12th Edition: Data Sufficiency
<< Back to 12th Edition Overview
Overall Changes
Which Problems Changed?
For an exact list of differences between the 11th and 12th editions, download the Data Sufficiency Problem List.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 Data Sufficiency problems in the 12th edition.
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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.作者: BeyondY 时间: 2010-4-20 11:41
本帖最后由 stream 于 2010-4-20 11:44 编辑
Topic Distribution
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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.作者: BeyondY 时间: 2010-4-20 11:41
本帖最后由 stream 于 2010-4-20 11:44 编辑
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.
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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.
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.作者: BeyondY 时间: 2010-4-20 11:42
本帖最后由 stream 于 2010-4-20 11:45 编辑
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.
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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.作者: BeyondY 时间: 2010-4-20 11:42
本帖最后由 stream 于 2010-4-20 11:45 编辑
Topic Distribution
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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.作者: BeyondY 时间: 2010-4-20 11:43
本帖最后由 stream 于 2010-4-20 11:45 编辑
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.
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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.作者: yoyolele 时间: 2010-4-20 11:54
好长呀，慢慢研究作者: sylvia1012 时间: 2010-4-21 02:00
可惜没有下载的作者: xiaoshuyiyi 时间: 2010-4-22 10:35
good作者: woshicat 时间: 2011-5-27 00:09
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