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Strongly supported inferences | Learn more

How do we recognize what is "strongly supported?"

Some questions on the logical reasoning section of the LSAT ask what additional information is supported by a stimulus. These are similar to questions that ask you to identify the implication or entailment, but a major difference is that for strongly supported questions, the answer doesn't have to be conclusively supported by the evidence. It just has to be the choice that is most supported of the ones you're offered.

How do we recognize these questions?

These questions are phrased in several ways. Here are some examples:
Which one of the following is most strongly supported by the information above?
Which one of the following can most reasonably be concluded on the basis of the information above?
The statements above, if true, most strongly support which one of the following?

Example

Birds and mammals can be infected with West Nile virus only through mosquito bites. Mosquitoes, in turn, become infected with the virus when they bite certain infected birds or mammals. The virus was originally detected in northern Africa and spread to North America in the 1990s. Humans sometimes catch West Nile virus, but the virus never becomes abundant enough in human blood to infect a mosquito.
The statements above, if true, most strongly support which one of the following?
(A) West Nile virus will never be a common disease among humans.
(B) West Nile virus is most common in those parts of North America with the highest density of mosquitoes.
(C) Some people who become infected with West Nile virus never show symptoms of illness.
(D) West Nile virus infects more people in northern Africa than it does in North America.
(E) West Nile virus was not carried to North America via an infected person.

How might we approach this question?

✓ Break down the stimulus into individual claims.
A good way to start is to separate out each claim in the stimulus, either mentally, or through shorthand notes:
1) Birds and mammals can be infected with West Nile virus only through mosquito bites.
2) Mosquitoes, in turn, become infected with the virus when they bite certain infected birds or mammals.
3) The virus was originally detected in northern Africa and spread to North America in the 1990s.
4) Humans sometimes catch West Nile virus, but
5) The virus never becomes abundant enough in human blood to infect a mosquito.
✓ Look for ways that premises interact and relate, giving special attention common terms.
Connections come from one claim interacting with another. A sign that two claims might connect is that they have a common term or idea. The first, second, and fifth claims above all involve the infection: they define who can infect whom. Taken together, they give the following picture of West Nile virus:
  • Bird and mammals (including humans) are infected by mosquitoes. Mosquitoes can be infected by some birds and mammals, but not by humans.
✓ Pay extra attention to strong and weak pieces of support.
The task is to find a choice that’s supported by information in the stimulus. So if the entire passage is "weak" (filled with qualifiers such as "sometimes" or "rarely" or "not all"), there's a good chance you can rule out choices that feel strong (featuring words like "all," "always," "every," "none" or "never").
✓ To test a choice, ask, “Can I point to any parts in the passage that actively support this claim?”
We don't recommend that you spend much time trying to make a prediction for "Strongly Supported" questions, since there could be so many claims that are legitimately supported. Instead, you can evaluate each choice by comparing it with the passage and asking, "Does anything in the passage actively support this claim?"
Try to avoid comparing choices with each other—sometimes, students get caught up in thinking about how a choice makes them feel, or they try to make a choice be right by adding assumptions to justify it, and these mistakes are easier to make when comparing the choices with each other.
Go and evaluate each choice in this way, and then click on the link below to compare your thinking with ours.

Summary for Strongly Supported questions

✓ Look for relationships.
✓ Diagram any conditional statements.
✓ Make a sketch if appropriate.
✓ Note strong language.
✓ Note weak language.
✓ Test the choices by asking, "Is it supported?"

Common incorrect choices

Wrong choices are those that aren't strongly supported by the information in the stimulus. Here are a few of the usual suspects:
  • Choices with language stronger than the passage's language. When it comes to making inferences, weaker claims are easier to support. So strong claims are less likely to be the answer, as they require more in the stimulus to back them up.
  • Be wary of choices that contain info that is outside the scope of the stimulus. If a choice introduces a new term or idea, it is unlikely to be supported by the information given.

Your turn!

Practice Question 1
Recent research indicates that increased consumption of fruits and vegetables by middle-aged people reduces their susceptibility to stroke in later years. The researchers speculate that this may be because fruits and vegetables are rich in folic acid. Low levels of folic acid are associated with high levels of homocysteine, an amino acid that contributes to blocked arteries.
Which one of the following statements is most strongly supported by the information above?
Choose 1 answer:


Practice Question 2
Sociologist: Climate and geology determine where human industry can be established. Drastic shifts in climate always result in migrations, and migrations bring about the intermingling of ideas necessary for rapid advances in civilization.
The sociologist's statements, if true, most strongly support which one of the following?
Choose 1 answer:


Practice Question 3
Mystery stories often feature a brilliant detective and the detective's dull companion. Clues are presented in the story, and the companion wrongly infers an inaccurate solution to the mystery using the same clues that the detective uses to deduce the correct solution. Thus, the author's strategy of including the dull companion gives readers a chance to solve the mystery while also diverting them from the correct solution.
Which one of the following is most strongly supported by the information above?
Choose 1 answer:


Practice Question 4
Most land-dwelling vertebrates have rotating limbs terminating in digits, a characteristic useful for land movement. Biologists who assume that this characteristic evolved only after animals abandoned aquatic environments must consider the Acanthostega, a newly discovered ancestor of all land vertebrates. It possessed rotating limbs terminating in digits, but its skeleton was too feeble for land movement. It also breathed using only internal gills, indicating that it and its predecessors were exclusively aquatic.
The statements above, if true, most strongly support which one of the following?
Choose 1 answer:


Practice question 5
Swimming pools should be fenced to protect children from drowning, but teaching children to swim is even more important. And there is a principle involved here that applies to childrearing generally. Thus, while we should restrict children's access to the soft drinks and candies advertised on television shows directed towards children, it is even more important to teach them __________.
Which one of the following most logically completes the passage?
Choose 1 answer:

Takeaways

  • There are often many possible inferences and it’s usually not possible to guess which one will appear among the choices for a strongly supported implication question. That’s typical.
  • The answer can be an inference that seems quite remote from the information discussed in the stimulus, or it can be a fairly obvious inference that almost seems to reiterate something mentioned in the stimulus. So don’t turn away from a choice just because it seems too obvious.
  • Never add your own assumptions to the information in the passage! This will take some practice, especially for some of the higher-difficulty questions, so be patient with yourself and keep reminding yourself to use only what’s provided to you in the passage.
  • Sometimes it can help to map out or draw some of the items from the passage. Consider the statement, “Last year, Country X sold 30% more books than it did the previous year, while Country Y sold 60% more books than Country X did last year but 10% fewer books than Country X did the previous year.” It would likely be very beneficial to sketch a quick chart to keep track of the relationships, so don’t hesitate on Test Day or try to keep everything in your head.

Want to join the conversation?

  • blobby green style avatar for user shileadeyoyin7
    What does it mean when it's said that for strongly supported questions, the answer doesn't have to be conclusively supported by the evidence? can you please put this in different words
    (8 votes)
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  • blobby green style avatar for user Wade Southwell
    "The scope then shifts to soft drinks and candies that are advertised on television. It’s important to restrict children’s access to the advertisements, but it’s even more important to—and this is where we can make a prediction."

    Does the original passage refer to restricting children's access to the advertisements or to the soft drinks and candies?
    (4 votes)
    Default Khan Academy avatar avatar for user
  • blobby green style avatar for user zh
    Can someone explain why the answer is E in the mosquito example?

    "So if a single infected human shows up in a new environment, the virus has no way of spreading." - I don't get this - isn't that how most diseases reach another place?

    "Therefore, it must have been some combination of mosquitoes and other birds and animals that carried the virus from northern Africa to North America." - Isn't this unreasonable because birds/mosquitoes/animals don't travel that far?
    (1 vote)
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  • blobby green style avatar for user sahand
    “Last year, Country X sold 30% more books than it did the previous year, while Country Y sold 60% more books than Country X did last year but 10% fewer books than Country X did the previous year.” can someone explain it? or send links to similar questions like this?
    (1 vote)
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  • spunky sam blue style avatar for user Ann Harper
    “The passage includes a principle and an analogy that applies [the] principle. In the swimming example, the principle appears to be that it’s more important to teach children to swim than to provide fencing for protection (even though both are important). So the priority is placed on empowering children.

    The original passage states “[the] principle” versus “that principle.”
    (1 vote)
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  • blobby green style avatar for user tynesemcdaniel
    Regarding your statement for answer choice E, you say " So if a single infected human shows up in a new environment, the virus has no way of spreading.

    However, E says "West Nile virus was not CARRIED to North America via an infected person". Can "carry" be interpreted as "spread"

    I interpreted answer choice E as a human being infected by a mosquito in northern Africa and did not travel to North America (i.e. did not carry the virus to NA).
    (0 votes)
    Default Khan Academy avatar avatar for user