GMAT Dense Reading Comprehension

Many GMAT test-takers find the GMAT Dense Reading Comprehension section to be one of the least favorite areas in the GMAT EXAM; however, it is possible to score well in this kind of question with a bit of practice. This article suggests some tactics that, if well applied, might just be what you need to attain that high-end GMAT score you are targeting. 

How Frequent Are the GMAT Dense Reading Comprehension Questions?

Assume one or two of the four assumed passages per verbal section will be these denser reading comprehension passages. Usually, the GMAT Dense Reading Comprehension questions involve one long paragraph about a technically specific topic you are probably not familiar with.

They are potentially reading comprehension-style content. They could also be integrated reasoning, multi-source content, or two-part analysis questions. Remember that in the verbal reasoning section, you may not want to skip these to save time because you may miss two, three, or even four questions in a row. The same applies if it is integrated reasoning or multi-source content. However, if it is a two-part analysis, you may have a little more flexibility since you can decide to guess and move on to maintain pace, knowing that it will only affect that one two-part analysis question.

Strategic implications

Read carefully and slowly to ensure that you comprehend the content. You cannot rush through it; you must engage with the passage through a dense reading comprehension mapping this article outlines.

Consider using the online whiteboard textbox when working on this kind of question, and in general, any reading comprehension passages and, to a degree, critical reasoning note-taking processes. This will facilitate sentence-by-sentence passage mapping. The online whiteboard textbox may not be very useful for the quantitative reasoning section or process elimination; however, the online whiteboard may come in handy on the at-home exam administration. Typing in notes may be faster than handwriting on a physical whiteboard or any other kind of whiteboard.

Use initials or shorthand to simplify unfamiliar jargon or acronyms. For instance, you could use a “variable” to represent long numbering nomenclature. Don’t even waste time trying to pronounce difficult, long, scientific names mentally. Use initials and shorthand and save yourself some precious time.

Synthesize the information as you go and note the location of your subject to better answer subsequent questions. Mapping does not only help you engage with the passage; it also tells you where to go back and get information. When you refer to your notes, you can quickly pinpoint exactly where to locate a given subject matter to answer a particular question. 

Dense Passage Mapping

• First, read a sentence and write a brief note summarizing its contents. If you do not engage with it immediately, you retain nothing.
• Read the following sentence and write a brief note summarizing its content to build a narrative from the prior sentence note.
• “Black Box” content that you cannot define for yourself or that seems to require outside knowledge by noting it with initials or shorthand. We will not worry about specific terms as we start engaging with this passage; definitely, you might not understand all the technical terms because you are probably not a botanist concerning this passage.
• As you continue to engage with these dense comprehension passages, you have a better idea of what is going on by the time you reach the end of the paragraph. As a result, you can make shorter summary notes as you go further along the passage.
• Since you have been taking detailed notes while engaging with the passage, there is no need to make an overall summary of the passage at the end of the map.

Sample Passage in GMAT Dense Reading Comprehension

Given its rugged coastline and absence of safe boat landings, ancient foraging on Anacapa Island must have been relatively challenging. Today, you can only find fresh water in an isolated spring with no perennial running water on an island segment. As a result, currently, the dominant vegetations are coastal bluff scrubs and coastal sage scrubs, with trees and shrubs limited primarily to two protected gullies on the northern slopes of west Anacapa and at Shepherd’s landing on Middle Anacapa. People commonly see California sea lions and harbor seals in the waters and rocks around the island.

Still, the absence of an extensive beach, except at Frenchy’s Cove on West Anacapa, limits the area for pinnipeds to haul out. The rocky coasts of Anacapa support rich rocky intertidal and kelp forest ecosystems. The island is more exposed to the warm, southerly waters of the California countercurrent than some of the other northern Channel Islands. This island’s steep slopes likely made it difficult for people to bring marine resources to sites on the top of the island, although access may have been easier in the past. Anacapa Island hosts enormous colonies of nesting birds, especially western gulls(Larus occidentalis) and brown pelicans (Pelecanus occidentalis), the latter of which use Anacapa and Santa Barbara Islands as a primary nesting area along the west coast of the United States.  

Sample Dense Passage Map

We will summarize a sentence at a time. S1 represents sentence 1.

S1) AI (Anacapa Island) was hard to have formed a time ago due to the rugged coast and no safe boat landings. 

“Dearth,” as used in this sentence, means “not safe”. It is best that you use your in-summary. If you don’t know the meaning, don’t worry; just note that we are talking about boat landings. 

S2) Today, AI only has fresh water in one spring

S3) CBS and CSS dominate AI vegetation, with trees and shrubs limited to two places in West and Middle AI.

Instead of “coastal bluff scrubs and coastal sage scrub,”, we simply write “CBS and C.”.

S4) Sea lions and seals in the water around AI but no beaches to rest on.

There is a lot of other information in the sense, and yet the essential communication here is the lack of beaches for sea lions and seals to rest on. It may not be necessary to concern yourself with the details or even the meaning of a word like Pinnipeds if you don’t know its meaning, even though you can make out the meaning from the context.

S5) AI has rich intertidal and kelp forest ecosystems.

You may include or talk about the water, but you probably will remember where it is anyway. Remember, as we go further, your summary will likely get shorter as you familiarize yourself with the passage.

S6) Steep slopes make it hard to reach the top of the islet and, may have been easier before

S7) Many nesting bird colonies, especially WG and BP, use AI and SBA as primary West US Coast nesting areas.

The scientific name is unimportant, and you can use initials to represent the names of the birds and other nouns in the sentence.

We will now use this map to answer questions from the passage. There is only so much room on the screen, and the map is probably going to disappear. Still, for the simple reason that we went through the passage so deliberately, we are probably going to remember where everything is.

Sample Detail Question

According to the passage, currently, you can find each of the following on Anacapa Island EXCEPT:

1. Sea lions
2. Harbor seals
3. Protected harbors
4. Freshwater
5. Nesting birds

We are looking for what you can’t find presently on Anacapa Island. From our passage map, we remember sea lions and harbor seals mentioned in sentence 4, underlined in the passage. We can hold choice C for now. There’s mentioning of fresh water in sentence 3, also underlined. There’s an indication that Nesting birds(pelicans) are on the island, sentence 7. By the process of elimination, our correct answer is choice C. But we can still read it back into the past just to confirm that there were indeed no protected harbors on the island. “Given its rugged coastline and dearth of safe boats”. Be on the lookout for unfamiliar paraphrasing meant to confuse you. Elimination is a good safeguard to protect yourself against any confusion resulting from such paraphrases.

Sample Purpose Question in GMAT Dense Reading Comprehension

Prediction: give a location where sea lions and harbor seals can ‘haul out.’

The reference to Frenchy’s Cove is most likely intended to

“Intended to” means we are looking for a reason why it is there. We can get where there’s a mention of Frenchy’s Cove from the passage map, so hopefully, there won’t be much need to go back to the passage. 

• Choice A doesn’t sound great, but Frenchy’s Cove is indeed an exception of sorts, so we can hold it with a squiggle.
• The reference to Frenchy’s Cove does not explain anything, not even about sea lions or seals. We can therefore rule out choice B.
• You can also eliminate choice C. (what alternative hypothesis?)
• Choices D and E are also way off. The mention of Frenchy’s Cove does not point to any instances of the same occurrence or even question anything. Italy is cited as the only place the seals and sea lions can haul out. 
• Choice A sounds vague and bland, but it is our correct answer. Once you have engaged and understood the passage, it is relatively easy.

Sample Inference Question in GMAT Dense Reading Comprehension

Prediction: Dominated by CBS and CSS

With which of the following statements regarding the vegetation of Anacapa Island would the author most likely agree?

1. Coastal scrubs are best adapted to an island environment
2. Many trees and shrubs require groundwater sources to flourish
3. A surplus of freshwater vegetation can lead to a water shortage
4. Protected gullies are necessary to support most island plant life
5. Cooler northerly waters can suppress biological diversity

A quick reflection on the passage

We have to go back to the passage and find the term vegetation. Then we will read around it, at least a sentence above and a sentence below. The passage map will also help determine how much you need to read. 

Today, fresh water is found only in an isolated spring with perennial running water on any of the island segments. As a result, vegetation is currently dominated by coastal bluff scrubs and coastal sage scrubs, with trees and shrubs limited primarily to two protected gullies on the northern slopes of west Anacapa and at Shepherd’s landing on Middle Anacapa.

• Coast scrubs are adapted to the island environment, and may be better than the trees and shrubs, but best adapted is an extreme statement, and we don’t have enough information to make such a conclusion. We can eliminate choice A. 
• We’ve got an isolated spring and no perennial running water. That means we have no water tied to these trees, and it is because of this that the vegetation is dominated by CBS and CSS. This matches pretty well with the passage, and choice B could be our correct answer.
• We don’t have much freshwater vegetation, and we don’t know what would happen in the event that we had a surplus. We can rule out choice C.
• For choice D, protected gullies may be required to support these trees and shrubs, but to say it is necessary for most island plant life is a rather big leap, and we are in no position to make such a generalization. So, we can eliminate choice D.
• Northerly and southerly waters are mentioned in the passage, but not here, where we are talking about vegetation. You must focus on the subject as well as the location. Avoid extrapolating to the larger passage when we are talking about a specific inference question such as this. 
• At this point, we can confidently select B.

GMAT Dense Reading Comprehension passage process

Take a look at the steps below:

1 – Execute a Detailed passage map

•  Determine the need for a sentence-by-sentence passage map. You have to decide early and commit, but if you do it you have to work through the pieces.
•  Take a shorthand summary note for each sentence as you go

2 – ID question subject and task

•  Determine what to look for using the passage map for location.

3 – Read what you need

•  Read at Least One Sentence Above and Below for proper context, except in a situation as we have in our sample question where the sentence above and/or below is clearly about a different subject.

4 – Prediction

• Predict what the answer should do to address the question task. It depends on the question asked and what the passage says about it. If it is about purpose, then “Why did the passage say it?” if it’s about inference, then “What must be?” based on that subject matter, and if you have an application question pattern, the “What matches it?” or potentially a kind of critical reasoning in reading comprehension. 

5 – Process of Elimination

• Focus on Actions and Descriptions for Objective Reasons to eliminate. You have to say why it is wrong. It could be extreme, a reversal, it introduces a new variable, etc., pinpoints something specific.
• Down to Two: Default to selecting the option with fewer direct terms from the passage and a less absolute claim, or simply put, go bland. Know that the exam is trying to obscure what the right answer is by using unappealing language

Dense Reading Comprehension Passage Example

Scuba-based observations and experiments helped promote the idea that positive interactions among species play key roles in the maintenance of biodiversity by facilitating the persistence of habitats created by foundation species, which are now often known as physical ecosystem engineers.

There was a clear demonstration of this critical role for Panamanian coral reefs in the early 1970s by elegant experiments following Peter Glynn’s observations that Trapezia crabs and Alpheus snapping shrimp living within branching pocillopora coral colonies prevented the crown of thorns starfish Acanthaster planci from feeding on the corals. Pocilloporid colonies, where there was an experimental removal of protective symbionts, suffered higher rates of destruction by A. planci, and coral diversity was higher where there was the prevention of the crown of thorns starfish from foraging.

Another example of positive interactions affecting foundation species, and ultimately, species diversity, comes from the Caribbean fore-reef slope.

The hypothesis indicates that sponges enhance the persistence of foliaceous corals on the steep forereef slope by binding the corals to the reef frame. 

Corals fell off the slope on manipulated reefs where divers removed the sponges from the coral interstices, resulting in elevated coral mortality. Later work in similar habitats showed that the underside of foliaceous corals supports an exceptionally high diversity of epifaunal invertebrates. Thus, the positive effect of sponges on foliaceous corals enhances community-wide biodiversity.

Which of the following would be most analogous to the ‘elegant experiments” mentioned in the passage?

1. A longitudinal study of the global population trends of an entire order of sea creatures
2. A closely controlled experiment involving starfish observed outside of their natural habitat
3. An experiment conducted in a laboratory determining the roles of various organisms in protecting endangered reefs
4. Using scuba equipment to build artificial coral  structures to investigate possible reactions with varying chemicals
5. Engaging a team of divers to physically relocate a species of seahorse from a coral reef habitat and observing the impact of the action

Here is another dense reading comprehension passage and a question. If this is the first question, then you need to decide if you want to read this specifically for the term referenced “elegant experiments,” or do you want to engage with the whole passage? We can see from the way it is constructed that this is a rather dense and technical passage. For the purposes of this article, let us engage with the whole passage.

Passage map

S1) Scuba observations and experiments promote the idea that species interactions are key to maintaining biodiversity.

S2) For Panamanian coral reefs, experiments following P.Gs observed that some organisms stopped starfish from feeding on the corals.

S3) Experiments showed that removing the organisms hurt reefs. Biodiversity was higher when starfish stopped feeding.

S4) Introduces another experiment showing species interaction improves the biodiversity of reefs.

S5) Intro the hypothesis that sponges enhance reef

S6) If you remove sponges, reef mortality increases.

S7) Later work showed high biodiversity on the underside of the corals

S8) Sponges lead to enhanced biodiversity for reefs in total 

Detailed explanation

Remember to use initials and shorthand in the way that suits you. This can be quite a long process, and often, the exam introduces difficulty by giving you more things to do. It will probably take you three to five minutes to break all this down and type it out, so you have to decide if it is a worthy effort. Remember also that there could be three or four questions here, and you can use this information for the subsequent questions. 

For the above question, we know our experiments are in sentences 4 – 7, where they removed the sponges or returned them and saw what happened. S3 is another experiment that involved the starfish. So basically, we are looking for something that would match the idea, where you remove or introduce something, and then make observations. 

Answer choice A is way too broad and does not match what we read, so can eliminate it. “Longitudinal means “it goes on for a long time.” But if you don’t know what it means, just focus on “entire order”. These experiments were pretty specific, and it automatically rules out choice A. 

Choice B is a reversal. The experiments didn’t take place outside of their natural habitat but rather inside. So we can eliminate this. 

Answer choice C is also a reversal. The experiments didn’t take place in a laboratory but in the field.

Choice D seems closer but is again another reversal since no artificial coral reefs were built. The experiments took place outside, in nature.

E is very similar. It only changes sponges and starfish for seahorses and clearly matches what we would expect from the experiments.

Main Idea Question

One of the tactics that the exam likes to use, they will put the main idea question at the end of these denser passages. 

Which of the following best describes the structure of the passage?

1. A claim is made, and examples are provided as support for it.
2. A theory is given, and evidence is provided for and against it.
3. A new scientific methodology is introduced and then tested in the field.
4. A hypothesis is offered and then refuted through the scientific method.
5. One experiment is described, and another offers an updated methodology.

We basically have all of it set up here in our passage map so we can go straight to elimination. 

Answer choice A sounds pretty accurate. Yes, there was a claim, and several examples are there in support.

A theory is given, and accurate, and evidence is provided for but not against it. So choice B is incorrect and can be eliminated.

For choice C, we don’t really know that there’s an introduction of a new scientific method.

No hypothesis has been refuted. All evidence available is in support, so choice D is out.

There’s no description for the experiment; the theory is. Answer choice is also out. We can confidently select answer choice A. 

Bottom line

This example illustrates how you can move more quickly through the questions in the GMAT Dense Reading Comprehension section once you have a good sentence-by-sentence passage map. This may not be your favorite thing to do, but try applying this kind of passage map to work through some practice passages and improve your performance on this relatively difficult aspect of the verbal section of the GMAT. 

Remember, the more you practice, the more you become confident in handling questions in the verbal section of your GMAT exams. On that note, spare some time to take advantage of the GMAT study resources available on our sites to keep yourself on track. Just like every other section, the GMAT Dense Reading Comprehension questions contribute to your final score. Therefore, it’s advisable to take time to practice all areas.