GRE Reading Comprehension makes up about half of the Verbal section. Passages range from roughly 50 words to almost 500. Most (about 75%) are just a single paragraph that's under 150 words. Subjects include the arts, sciences, and humanities as well as a smattering of non-academic topics. You might think that longer passages or less familiar subjects (as, say, Physics might be to an English major) would yield tougher questions. But an analysis of official practice tests shows that question difficulty depends, as it should, on the level of comprehension a question demands.

Three of the official practice tests from ETS—two in The Official Guide to the GRE and one in The Practice Book for the Paper-based GRE—offer a measure of question difficulty: the percentage of test takers who answered correctly when the question was on a real exam. Using this data, you can get a sense of which types of questions tend to be harder. For instance, if you classify GRE Quantitative questions by math type and then rank them by percentile, you'll find (perhaps as expected) that algebra problems are among the toughest.

You can likewise group and rank GRE Reading Comp questions. But how should you classify them?

Longer Passage ≠ Harder Questions

Say you do so by passage length, based on the hypothesis that the more you have to read for a question, the harder it will be to answer. This hypothesis turns out to be mistaken. Questions tend to get easier as passages get longer.

Suppose you classify questions by passage topic, much the way you'd group Quant questions by math type. You'll find that the arts & humanities (35% of all passages) are linked to questions that around half or more of all test takers get right. The social sciences (10% of all passages) also correlate with less difficult questions. Meanwhile, the questions that most examinees get wrong are linked to the natural sciences (40% of all passages) and non-academic topics (15% of all passages).

But GRE Reading Comp doesn't test subject knowledge. It tests reading skill. So the link between different subjects and different levels of difficulty is just a coincidence.

Deeper Comprehension = Harder Questions!

To see what really determines difficulty level in Reading Comp, classify the questions by the sort of skill you have to exercise or, put another way, the type of task you must perform. You'll discover that every question has you take what you've read and do one of the following:

1. Paraphrase or summarize (35% of all questions)
Examples: The Practice Book §3 no. 1, 13, 20, 21
2. Draw conclusions or parallels or infer purposes or intentions (50% of all questions—MOST COMMON)
Examples: The Practice Book §3 no. 10, 11, 12, 22 and §4 no. 20, 21
3. Resolve or explain an issue or analyze and evaluate arguments or assertions (15% of all questions—MOST DIFFICULT)
Examples: The Practice Book §3 no. 14, 25 and §4 no. 15

A, B, and C reflect different kinds of comprehension. Educators call A Literal, B Inferential, and C Critical. Literal comprehension questions tend to be easiest: you just need to recognize restatements of ideas expressed in the text. Inferential questions are usually harder: you have to spot claims that can be derived from the text or roles that can be ascribed to it. Critical questions are often hardest: you need to appreciate how new information will affect—support, defeat, or explain—the content of the passage.

Let's revisit the link between passage topic and question difficulty. Why do questions about non-academic and natural sciences passages pile up on the tougher side, while ones about a & h and social sciences passages do not? The former include 5 times more Critical comprehension questions.

When you're getting ready for GRE Reading Comp, don't fret over the length or subject matter of the passages. Focus on the types of questions you're asked. That's where the true challenge lies. Maximizing your score will require mastering the sorts of questions that push you not just to absorb the text but also to extend and evaluate what you've read.

Want to try some tough Reading Comp questions—and see them answered and explained? Check out these posts:

For more help preparing for GRE Reading Comp, also check out The PowerScore GRE Verbal Reasoning Bible.