LR

Sufficient Assumption

Question frequencyCommon

Common question stems

  • "The conclusion drawn above follows logically if which one of the following is assumed?"
  • "Which of the following, if assumed, allows the conclusion above to be properly drawn?"
  • "The argument’s conclusion can be properly inferred if which one of the following is assumed?"
  • "Which above, if assumed, would do most to justify the conclusion?"
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This lesson references LawHub questionsOpen LawHub in a separate window and use split-screen to follow along

Introductory Example Question

Sufficient assumption questions ask us to choose an answer choice which, if taken to be true, would prove the conclusion of the argument.

Navigate to the question below in LawHub and attempt to answer it, and then continue to the paragraph below.

LawHub QuestionPT 114, S1, Q1Evaluate the question on LawHub and then continue reading the article below for the explanation

If you read the question above on LawHub, identified the conclusion, and said “Wait, employees of a company? New health program? There’s no evidence to make a conclusion about these concepts” then you’re on the exact right track!

The evidence in the stimulus tells us that a person suddenly increasing their amount of exercise can cause them to be at higher risk of heart attack. But then… we conclude that some employees will be at risk of heart attack due to a new program at their company? That’s completely unrelated to the evidence…

-Unless we assume that the new health program will make the employees suddenly increase the amount that they’re exercising!

We know from the evidence that sudden increase in exercise can lead to heart attacks. But the stimulus concluded that employees with this new program are going to be at risk of heart attacks. So, to prove the conclusion, we would assume that the new program constitutes a sudden increase in exercise for the employees. Therefore, the correct answer choice is (A). If answer choice (A) is applied to the argument, then the conclusion is proven!

Approach

A good first step for sufficient assumption questions is to look for new information that’s introduced in the conclusion.

We want to be aware of any “gaps” or "leaps" in the reasoning between the evidence and the conclusion. The correct answer will often connect the unproven information that's introduced in the conclusion to the actual evidence (ie. "fill the gap," or "connect the dots") in a way that proves the conclusion. Try to predict the answers for these questions by bridging the gaps in the logic.

If this all seems confusing or hard to follow, attempt the questions below and thoroughly read the explanations for each! As you practice your brain will pick up on the pattern and you'll find yourself predicting the answers for sufficient assumption questions.

Pro tip: even if you feel confident in getting these questions correct through evaluating the answer choices or by process of elimination, you should practice predicting them. If you get good at spotting the gaps before even reading the answer choices, you will greatly increase your speed on these questions and you will be far less likely to fall for trap answers.

"Bridge the gap" Examples

LawHub QuestionPT 101, S3, Q10Look for the new information that's introduced in the conclusion!
LawHub QuestionPT 112, S4, Q1Look for the new information that's introduced in the conclusion! Try to predict/pre-phrase the answer
LawHub QuestionPT 112, S4, Q15
LawHub QuestionPT 109, S3, Q23Here we'll bridge the gap while evaluating a trap answer that swaps sufficient and necessary conditions.

Another Sufficient Assumption Pattern: Eliminating Other Explanations or Solutions

Navigate to the question below and attempt it. Then keep reading for the explanation.

LawHub QuestionPT 109, S4, Q2

For this question students often struggle to see the "gap" in the logic of the stimulus. But let's break it down: the conclusion is that the center can't operate this year. The evidence given is that the center needs $2.5 million to operate, and the board of trustees are only going to give them $1.5 million.

So, the board can't give the center $2.5 million, so the stimulus concludes that the center can't get $2.5 million. See the gap (board budget vs total money collected by the center)? This conclusion isn't proven at all! What if the center starts a Go Fund Me and raises the money? What if one of their alumni is a tech billionaire who donates the money?

This stimulus commits the Flaw of describing a situation with multiple explanations and then concluding that one is definitely correct without eliminating the viable alternatives. Remember that Sufficient Assumption questions are tasking us with proving the conclusion. So to remedy this flaw, we need to eliminate all other options! That's the pattern.

Pro tip: You will see this flaw presented in the stimulus of Necessary Assumption questions as well. Note that for those questions you may only have to eliminate one viable alternative out of many, because the question is asking for something that needs to be assumed. For Sufficient Assumption, where we are asked for an assumption that would prove the conclusion, we need to eliminate all of the viable alternatives. This may seem like a subtle distinction, but you can navigate to corresponding section of the (LINK Necessary Assumption LINK) section to see this concept in practice.