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Additional evidence | Quick guide

What supports or weakens this position?

There are two kinds of additional evidence questions: strengthening evidence and weakening evidence.
Strengthen questions ask you to select the choice that provides the best additional evidence to support a given claim. Your task is to evaluate the new information provided in each choice and pick the one that, if it were true, would strengthen a particular argument made in the passage.
Weaken questions also give you a claim or position from the passage, but this time you have to pick the choice that, if true, would weaken that claim.


You will often see the words “strengthen” or “weaken” in the question itself. But you might also see synonyms such as “support,” “bolster” or “reinforce” (for strengthen questions) and “undermine,” “challenge” or “call into question” (for weaken questions).
  • “Which one of the following would, if true, most weaken the author's argument as expressed in the passage?”
  • “Which one of the following, if true, would most seriously undermine the explanation proposed by the author in lines _____?”
  • “Which one of the following, if true, would most strengthen the author’s contention that _____?”
  • “Which one of the following, if true, would bolster the claim that _____?”


Put it in your own words: It can be helpful to sum up in your own words the idea that you’re trying to strengthen or weaken before considering the choices.
It’s not enough to be about the same topic: Keep in mind that what you’re looking for is information that has an impact on the plausibility of the position, explanation, claim or evidence that the question is asking about. It isn’t enough that a piece of information in a choice is about something that the passage is concerned with—or even about the particular thing that the question is about. The correct choice has to have a real impact on the strength of the thing being asked about.
Proof isn’t required: The answers to these questions usually don’t have to conclusively establish or definitively refute the claim, position (or other thing) being asked about. It’s enough for the correct choice to increase (for strengthen questions) or decrease (for weaken questions) the likelihood that the claim or position in question is right.

Additional variants

New evidence can affect claims in a variety of ways. Sometimes, a claim in the passage will depend on a certain supposition being true, and the additional evidence in the correct choice will undermine (or strengthen) that supposition, and thus undermine the whole argument.
In other questions that ask about what would weaken or strengthen something in the passage, the additional information given in the correct choice might be related to the passage in other ways.
Strengthen variant:
  • The additional info might suggest that something is true that would have been predicted given what the passage says, and thereby strengthen the case made in the passage.
Weaken variants:
  • The additional info might suggest that something that would have been predicted – according to claims or principles or info in the passage – in fact doesn’t or isn’t likely to happen.
  • The additional info might suggest that a generalization that the passage relied on does not hold up in the particular case mentioned in the choice.
  • The additional info might suggest that a claim made in the passage is unlikely to be true.

Tempting wrong choice types

Supports rather than weakens, or vice versa: Make sure to pay attention to whether the question is asking for strengthening or weakening evidence. There’s almost always a wrong choice that does the opposite of what you’re being asked to do!
Too weak: Sometimes a single word—“some,” “might,” “may,” “can,” etc.—can make a choice too weak to have a significant impact on the author’s argument. You’re always looking for the choice that would most undermine or strengthen the argument.
No impact: Most other wrong choices will either be unrelated to the claim (and thus have no impact), or they’ll be on the same topic but still don’t affect the strength of the claim in any way. Remember: no matter what, the new evidence has to have a clear effect—and the right effect—on the strength of the claim.

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