What Quant is Tested on the GMAT? [Detailed Analysis of GMAT Topics]

What Topics are Tested on the GMAT?

I see this question every week on GMAT Club - what topics or subjects are actually tested on the GMAT? Usually I say and give some general ideas such as arithmetic or geometry and then the arguments begin as to which topics are easier and which are harder and so on and so forth. Usually nobody gets anywhere since everyone's test experience is a bit different. For some, the test gives them hard DS questions while others get Probability and Combination PS questions. Then a brilliant (?) idea was born - what if we survey all of the Free GMAT Prep Questions (there are close to 2,000)? We have the tags/categories and know the difficulty... that can help us get a good idea about the distribution of topics and actually will show us exactly what is tested on the GMAT. Of course I thought the job would be a lot more exciting and easier but about 15 hours in, I was only scratching the surface. The data needed to be scrubbed and cleaned to make sure only GMAT Prep questions were included from Tests 1 and 2 and tags had to be organized and difficulties distributed.... now about 30 hours in, I have some results to share

Jan 13 Update: Verbal Topics Have been Posted Here


1. Difficulty of Questions
What I wanted to know first is - what are the hardest questions in the GMAT Prep? What is the distribution of Question Difficulties? What Percentage of the GMAT prep Questions is Hard vs. Easy?
We had to designate the difficulty based on the GMAT Club Timer and we set it to be:
Easy Questions: 1-24
Medium Questions: 25-50
Hard Questions: 51-99
(Sample size: 2,045 questions, excluding RC)

Based on the scale, 23% of all GMAT Prep tagged Questions are Hard, 50% are easy, and 27% are medium.
This is somewhat as expected... I was expecting to see perhaps 50-35-15 or something like that distribution but this may be due to how we decided to draw the lines in terms of difficulty. However, one thing is clear, the majority of questions are Easy. There are also different distributions within each of the categories: DS, PS, CR, and SC (RC was not tested/included in this project).




The two most difficult question types on the GMAT are DS and CR. Both have about 29% of questions designated as "hard" vs. PS that has only 16%. One reason DS is much harder (twice as hard?) is that you cannot back-solve with PS and the question type is just less logical/common and also has more traps to be set.



2. Topics - What is Actually Tested?

• 40% - Word Problems
• 28% - Arithmetic
• 24% - Algebra
• 8% Geometry

Quant Topic Distribution
Tag	Percentage	Count
Word Problems	13%	196
Number Properties	9%	128
Algebra	8%	123
Inequalities	7%	109
Statistics	7%	108
Percent and Interest	6%	83
Arithmetic	6%	81
Fractions	5%	74
Geometry	4%	66
Divisibility	4%	62
Coordinate Geometry	3%	49
Exponents	3%	48
Overlapping Sets	3%	37
Work/Rate Problems	3%	37
Probability	2%	35
Distance/Rate Problems	2%	32
Combinations	2%	31
Sequences	2%	29
Absolute Values	2%	28
Remainders	2%	26
Must or Could be True Questions	2%	24
Min/Max Problems	2%	23
Functions and Custom Characters	1%	18
Roots	1%	15
Graphs and Illustrations	0%	6
Mixture	0%	4

Total: 1,203 Questions and 1,470 Tags in the sample; this combines PS and DS questions from the Free GMAT Prep Tests 1 and 2.


It is interesting to see and note that combinations and probability are only 4% of the total pool of questions (2% each respectively). Geometry is 8% with about 4.5% regular geometry and 3% for Coordinate Geometry, so it is surprising that there is as much coordinate geometry as there is regular geometry.


3. Difficulty of Topics
I am honestly surprised at the result of my data... it is telling us that the hardest GMAT Prep Questions (on average that is) are from the Absolute Values and Must Be True Categories in PS and DS (likely DS since that's where most of the difficult questions are hiding). The average difficulty of all questions based on the GMAT Club timer is 32.2

Some conclusions:

• You definitely want to master the BIG "Green" topics such as Word Problems, Fractions, Arithmetic, Number Properties. Untile you go through the "Green" zone, you wont' get to the Yellow and Orange zones that have the most points
• These are averages and while GMAT tests many topics, tests are adaptive so while we may indicate that the average difficulty of a probability questions is not that HIGH, it may actually result on the real test in getting a very difficult question. These are averages!
• Anything that is Yellow and Orange is "difficult" despite not being so overwhelmingly or overpoweringly difficult

The Same Data in a Table Format:

Quant Topics	PS Link	DS Link	Count	Average Difficulty
Absolute Values	PS	DS	28	59
Must or Could be True Questions	PS		24	52
Mixture	PS	DS	4	48
Remainders	PS	DS	26	43
Overlapping Sets	PS	DS	37	43
Coordinate Geometry	PS	DS	49	41
Inequalities	PS	DS	109	40
Divisibility	PS	DS	62	39
Geometry	PS	DS	66	36
Distance/Rate Problems	PS	DS	32	36
Percent and Interest	PS	DS	83	34
Min/Max Problems	PS	DS	23	34
Fractions	PS	DS	74	33
Probability	PS	DS	35	33
Functions and Custom Characters	PS	DS	18	32
Number Properties	PS	DS	128	31
Statistics	PS	DS	108	30
Combinations	PS	DS	31	30
Sequences	PS	DS	29	29
Work/Rate	PS	DS	37	26
Roots	PS	DS	15	26
Word Problems	PS	DS	190	26
Arithmetic	PS	DS	81	26
Exponents	PS	DS	48	24
Algebra	PS	DS	123	22
Graphs and Illustrations	PS	DS	6	10

Average Difficulty: 32.2


Hope this is useful to someone. Let me know if you have any questions or spot any surprises.
Also, plepase consider reading the Online GMAT Prep What-if Scoring Analysis
At this point I have ran out of time to do the same analysis for the Verbal as well as Tests 3/4 and 5/6 - that will be coming next week