GMAT Verbal: Inferences

You’re having lunch with your friend Jane, and you suggest getting hot fudge sundaes for dessert; Jane tells you that she doesn’t eat hot fudge sundaes. In real life, you could draw several valid inferences from this: she’s lactose intolerant, she has sensitive teeth and so can’t eat frozen desserts, she’s on a diet and trying to avoid sweets, or maybe she just doesn’t like ice cream or hot fudge. In real life, those would all be acceptable inferences, because the real-world definition of infer is to do any of the following:

1. to derive by reasoning; conclude or judge from premises or evidence: e.g., They inferred his anger from his heated denial.
2. (of facts, circumstances, statements, etc.) to indicate or involve as a conclusion; lead to.
3. to guess; speculate; surmise.
4. to hint; imply; suggest.

“Infer” is, as you can see, a word with fairly flexible meaning. We most often use it in day-to-day life to mean “make an educated guess.” If your friend Jane says she doesn’t eat hot fudge sundaes, you apply your existing knowledge about the possible reasons someone could have for not enjoying the hot fudge and ice cream deliciousness, and you make an educated guess as to what her reasons could be.

Inference question types are pretty unique. Unlike Assumption, Evaluate, Strengthen, Weaken, and Role of Bold, Inference questions are not based on arguments. And unlike Assumption, Evaluate, Strengthen, Weaken, and Explain Discrepancy, Inference questions are not usually about presenting your brain with some form of cognitive dissonance.

GMAT Verbal Inference Questions

On the GMAT, however, “inference” has a different meaning. Think of inferring as the process of deriving the strict logical consequences of assumed premises.

On the GMAT, therefore, if you are told that Jane doesn’t eat hot fudge sundaes, you can derive two logical consequences from that premise:

1. If Jane is eating, has eaten, or will eat something, it isn’t a hot fudge sundae, and
2. If someone is eating, has eaten, or will eat a hot fudge sundae, that person is not Jane.

The correct answer to an inference question on the GMAT will follow directly from the evidence provided; it is NOT merely an educated guess but is instead the logical consequence of the assumed premises.

Notice that just based on six words—“Jane doesn’t eat hot fudge sundaes”—we can draw two possible inferences. Now think of how many words you might see in the average GMAT question, and you’ll understand that inference questions, unlike other types of questions, don’t lend themselves well to prediction. Trying to guess the correct inference being drawn from several sentences worth of statements is generally a waste of time.

Your best bet in approaching GMAT questions that ask for inferences is to use the process of elimination. Eliminate answers that are just “educated guesses,” answers that aren’t necessarily true, answers that are too extreme, and of course, anything irrelevant. Your answer will be the one choice that follows strictly from the statements in the question.

How to Learn GMAT Critical Reasoning

In addition to learning the patterns surrounding analyzing Plans, Predictions, and Causal Explanations, we should also be learning a little index card’s worth of technique for each of these seven main question types.

For each question type, we’re trying to memorize the following:

• What keywords in the question stem tell me it’s this type of question?
• What am I reading for in the paragraph?
• How, and to what extent, should I pre-phrase a potential correct answer?
• Are there any tendencies relating to the paragraph or the answer choices?

So let’s make sure everyone has a great index card for Inference questions.

What Keywords in the Question Stem Tell Me It’s an Inference Question?

Here are a few examples of Inference question stem wording:

– If the statements above are true, which of the following must be true?
– If the information above is correct, which of the following is most strongly supported?
– The claims above most strongly support which of the following assertions?
– Which of the following can be properly inferred from the passage?

One of the most salient features is the noun being used to describe the paragraph we read. Remember, when we’re doing Strengthen, Weaken, Evaluate, and Assumption, we’re going to almost always see the paragraph described as one of the following: argument, plan, prediction, or hypothesis. Those nouns connote the idea that there will be an opinion within the paragraph:

Arguments have an opinionated conclusion, based on some (untouchable) evidence.
Plans have the opinion that if we follow this plan, we will achieve the stated goal.
Predictions contain a conclusion that is in the future tense, thus an opinion.
Hypothesis means that our author will be opining some ‘causal explanation’ for a curious fact.

With Inference, you see that the nouns being used connote that we’re just reading some facts: statements, information, claims, or passage

Inference may be asked in the “must be true / properly inferred” style (indicating 100% provability), or they may be asked in the “most strongly supported” style (indicating that the correct answer is the most provable claim, even if not 100% provable).

Students often confuse “most strongly support” Inference question stems with a Strengthen question stem.
INFERENCE:   The statements above most strongly support which of the following conclusions?
STRENGTHEN: Which of the following, if true, most strongly supports the argument?

The two big differences are that Inference deals with statements/information, while Strengthen deals with arguments/plans/hypotheses, and that in Inference questions the paragraph provides support for the correct answer choice, while in Strengthen questions the correct answer choice provides support for the paragraph.

What am I Reading For on an Inference Question?

Remember, Inference is specifically not giving us arguments and plans. We’re just getting two or more facts and being asked which answer is derivable from those facts.

To draw a valid inference = to draw a valid conclusion. Validity means that we can derive an idea from the available evidence without speculation or exaggeration.

In Reading Comp, correct answers to Inference questions usually paraphrase something we know from the passage, but they use new and unexpected wording or some sort of inverted syntax. Pretend that in line 20 of an RC passage we are told that “George Washington wore a military cap to his Inauguration as the first President of the U.S.”

Can we infer that
(A) He wore the cap because it was a cold January day.
(B) All former generals have to wear military caps.
(C) He thought it flattered his deep blue eyes.

Of course not. None of those are provable claims. They are speculations or overstatements.
We can infer weird restatements such as these:
(A) Not all Presidents are sworn in hatless.
(B) On the first day of the American Presidency, at least some parts of the first President’s scalp were not visible.
(C) People seeing George Washington for the first time at his Inauguration could not have conclusively determined Washington’s level of baldness.

The personality of CR Inference questions is a little different: the correct answer almost always pulls together two or more facts provided.

Pretend we read a CR Inference paragraph that said, “George Washington wore a military cap to his Inauguration as the first President of the U.S. He wore this same cap during the Battle of Yorktown.”

Can we think of a safely worded claim that pulls information from both sentences?
A) Presidents do not always begin their terms wearing totally new garments.

“Presidents begin their terms” pulls info from the first sentence. “Not wearing totally new garments” comes from knowing that the cap he wore on Inauguration day had been worn before at the Battle of Yorktown.

So, in summary, what are we reading for when we read an Inference paragraph? We are reading for two or more facts that could be synthesized in order to derive a true claim.

Very often, this synthesis comes about because the two or more facts contain some overlapping piece of information (in this case, both facts referenced GW’s hat). There are four main types of Inferences:

1. Math-y

• Spain beat France in regulation. However, France scored more goals in the 2nd half.
  Infer: Spain scored more in the 1st half / Spain’s margin of victory in the 1st half was larger than France’s margin of victory in the 2nd half
• My rent is scheduled to increase next month. Nonetheless, it will represent the same proportion of my income.
  Infer: My income is also going to be higher next month (increasing by the same multiplier)

2. Apply a Rule

• For a grilled cheese to be delicious, the cheese must be melted into liquid form and the bread must be toasted but not burned. The cheese Patrick is using to make grilled cheeses for his wedding feast is so cold and dense that liquefying it will take at least five minutes of high heat, which is more than enough time to burn the bread he’s using.
• Infer: At least one item at Patrick’s wedding feast will not be delicious. (many different ways we could state the inference, but applying the rule to my specific situation tells us that these will not be delicious grilled cheeses)

3. Causal

• Patrick always buys his shampoo at CVS. Recently, CVS stopped offering Herbal Essences shampoo. As a direct result, the cost of Patrick’s hair care went up.
• Infer: Patrick was previously buying Herbal Essences. He is now buying a different shampoo, and that new shampoo costs more.

4. Straddle the Pivot

• Patrick is a mean teacher. However, he gives his students candy.
  Infer: Not all candy-giving teachers are nice.
• People think that New York City is the most expensive city in the country. Yet, the cost per square foot of real estate in San Francisco is much higher than that in New York City.
• Infer: New York City is not necessarily the most expensive city in the country.

Math-y and Rule-based inferences tend to feel more like Must Be True. Causal and Straddle the Pivot tend to go more with Most Strongly Supported.

How, and to What Extent, Should I Pre-phrase a Potential Correct Answer on Inference?

We are reading to see if we can combine two or more of the provided facts to derive some true claim (or incredibly likely claim, if we’re doing “most supported”). When we successfully find an available inference we can make from the paragraph, we should certainly anticipate that the correct answer will probably reinforce or reward that.

But we should stay very flexible. Ultimately, the only standard of right or wrong on Inference is, “Could you prove this answer choice, using only the information provided in the paragraph?”

So the correct answer is under no obligation to tie everything together or to present the ‘coolest’ takeaway. The correct answer just has to be the most provable claim. Keep any inference you discovered in your mind as your mantra of what the correct answer will probably sound like, but give each answer choice a fair hearing by asking, “Could I prove this, using the statements I just read?”

What will frequently happen with correct answers is that they will be a spin-off inference of what we inferred. For example, if we inferred “Spain outscored France in the first half”, the correct answer might say “Spain scored at least once in the first half”. If we inferred “the cost of paying for parking was more than the combined costs of taking the train and taking a Lyft from there”, the correct answer might say “The Lyft ride was cheaper than the cost of paying for parking”.

Those answers can feel annoying, because we’re like, “Yes, but I know even more than that!” It doesn’t matter. You can sign off on the truth of those answers, so they are correct. In general, expect that when you walk out of your real GMAT, you’ll reflect on all the stuff you studied that you never even saw on your test and feel like, “Yes, but I know even more than that!”

What About Answer Choice Tendencies?

Since we are trying to find the most provable claim, this is a question type for which strong or new language in the answer choices should be a big red flag.

There are three big categories of strength of language:
CERTAIN: all, only, never, unless, requires, must
MORE THAN 50%:  most, typically, generally, usually, likely, tends to, probably
AT LEAST ONE:  some, sometimes, can, may, might, not all, not always, need not

When you’re doing Reading Comp, Assumption, or Inference, you should always consider the two stronger levels of language to be red flags; this doesn’t mean they’re automatically wrong, but it means you have to research in the passage whether you’re justified in saying something this strong.

Meanwhile, when you’re doing Strengthen, Weaken, or Explain Discrepancy, all of which begin with the words “Which of the following, if true, most …”, then the weakest level of language is a red flag. An answer choice isn’t going to have much impact if it’s only saying “at least in one case this is true”.

Inference Questions: Takeaways

If we want to improve at Inference questions on RC and CR, we need to remember that we’re not allowed to speculate or exaggerate. We’re only allowed to pick answers we feel like we can derive from the provided information. If nothing is 100% provable, then pick the most provable option. If you need to guess quickly, avoid strong language.

For CR, you can go one layer farther and proactively read the paragraph looking for facts that can be combined. In particular, if you see quantified wording, look for a math-y inference. If you see causal wording (e.g., “because of this”, “due to”, “this allows”, “this makes possible), look for a causal inference. If you see a Rule (e.g., “if/then”, “always”, “only”, “ensures”, “requires”, “guarantees”), look for an inference you can make by applying that rule to a specific situation. If you see the paragraph is divided up by a but / yet / however, think about what safely worded claim you could create that would integrate both sides of that pivot.

GMAT Verbal Practice Questions

Let’s look at two sample GMAT-type questions. The first will walk you through how to solve an Inference question. The second one, try the method on your own:

GMAT Verbal Question 1

Step 1: Identify the Question Type: The keywords “properly inferred” in the question stem are a sure sign of an Inference question.

Step 2: Untangle the Stimulus: Randall’s comments can be reduced to an if/then statement: If productions of his plays are poorly done, then they don’t provide a true measure of his skills as a dramatist. And many amateur theater groups perform his plays poorly.

Step 3: Predict the Answer: While we may not be able to predict what the correct answer choice will infer, we can be certain that it is a statement that must be true if we accept Randall’s statement as true.

Step 4: Evaluate the Choices: Since many amateur productions are poorly done, and no poorly done production provides a true measure of Randall’s skills, it must be true that at least some amateur groups’ productions do not provide a true measure of his skills, so (E) is correct. Don’t be afraid of (E) because it seems “obvious.” This is not a test-maker trick—an “obvious” answer is one that must be true, so it works as a valid Inference.

(A) seriously distorts Randall’s statement. Just because some amateur productions don’t do him justice doesn’t mean that there are other productions that do. If the GMAT tells you that some marbles are red, you can’t automatically infer that some are not red.
(B) is another sort of distortion. Randall’s statement about certain poorly done productions in no way guarantees anything about productions that aren’t poorly done.
(C) is far too extreme. Randall does establish a correlation between poor production quality and failure to provide a true measure of his skills, but that correlation has only been established for a certain set of productions and can’t be extended to all productions.
(D) attempts to extract a broad principle from Randall’s statement, but his statement is too particular to allow this kind of extrapolation.

The answer is (E).

GMAT Verbal Question 2

Only one of these answer choices MUST be true; let’s take a look at the options:

A. We only know about percentages, or proportions, so we can’t draw inferences about dollar amounts.
B. No information is provided about competition for either Interment Services or Toxic Household Products.
C. This is the correct choice; Interment Services has a profit to transactions ratio of 50%:30%, or 5:3, while Toxic Household Products has a ratio of 50%:70%, or 5:7.  Therefore, the Toxic Household Products Division is doing more than twice as many transactions as the Interment Services Division, but yielding the same profits.
D. Product lines are not discussed, and therefore can’t be the subject of an inference.
E. Per-family spending is never mentioned, so we can’t infer anything about it.

There’s a pattern here: if it’s not mentioned, an inference can’t be drawn about it.  Inferences MUST be supported by the evidence provided; remembering this one concept will give you a solid start in conquering inference questions on the GMAT.