Sufficient Assumption | LSAT Logical Reasoning

Sufficient Assumption questions in Logical Reasoning are all about finding the missing link in the argument. Learn how to use conditional logic to find the gap in the argument's reasoning.
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[@kamacazi9639]

Oh my God this video is heaven sent. I was having major problems trying to figure out how to answer sufficient assumption questions and I followed LSAT Lab strategy and I got all correct and boosted my score from 15/23 to 20/23 cause it was an area of weakness for me. Please follow their strategy it does put the question into a visual perspective. A--B--C--D A and B are usually two sets of evidence given in the question; the evidence can be a conditional relationship or just stated facts that you have to link together, D is always the conclusion. You have to find C or the link between B- D which is the sufficient assumption. If you map the question like this I guarantee you’d figure out what the assumption is. It is usually a mix between the B and D. You have to find a common ground that would link the conclusion to the premise B and that usually gives you C or the sufficient assumption. Thanks LSAT Lab.

[@randomvideos_658]

So helpful, finally someone I understand easily when explaining. Thank you!

[@ariannaramirez3953]

THIS IS SO HELPFUL!!! I got the example problems right. I also really appreciate how you clearly explain why the wrong ones are incorrect

[@ts4426]

The part where you ponder on how all of the aluminum of group L possibly may have not made it over to Group M using the mixing bowl mindset is where I struggle the most. My mind has the hardest time coming up with these "what if" scenarios that would disprove the conclusion. Ive got to learn how to think this way.

[@makedadesouza6478]

Thank You!

[@lraoux]

I fell for the Negation choice (Answer D) about Murray on the executive board/Admin question; thought B was out of scope. One important takeaway from this lesson is that SA questions can be tricky because of irrelevant relations (I noticed this in another SA question). Murray, who is in the conclusion of the stimulus, is actually irrelevant in finding the right answer choice. Another key takeaway is that answers that seem too strong make for good choices, and are often better than assumptions weaker in degree. In contrast, for inference/strongly support question types, strong answer choices generally should be eliminated, as they are harder to prove, so it’s important to know the question type.

[@stephaniewang8807]

Thank you! I also fell for D, and I appreciate your analysis.

[@christinea6318]

I don't understand why this isn't clicking :'(

[@user-zf1en8im7i]

U should research conditional logic before watching this it will belp

[@riyakapoor3218]

Amazing videos

[@riyakapoor3218]

Thankyou please make more for lsat india!!

[@Stunninjavi]

Is possible to have an answer choice be both necessary and sufficient? Or is it also possible that one answer choice can be necessary but not sufficient for the same given argument? If so, can you provide an example? Thank you! And by the way, great content!

[@tashanalucero1793]

Thanks!

[@nicolewinn2927]

I wish I could shake your hand, or give u a hug. Thank you so much..

[@As_Sulay]

8:01

[@LawsIntuitive]

Eye helpful explanation

[@randomvideos_658]

Do you do personal tutoring sessions? If so, I am interested.

[@LSATLab]

We do. Both Patrick and I tutor at lsatlab.com. With a free account you can purchase tutoring sessions for $50 per 30 minutes or you can subscribe to our Digital Tutor plan for $199 per month that includes four 30-minute tutoring sessions per month.

[@jinsdancelog8152]

Do we solve Necessary Assumptions that require linking the same way we do Sufficient Assumption questions? I'm stumped on finding a difference between the two if there are any. I'd really appreciate some help with differentiating the two because I feel like I'm answering a necessary assumption question the same way I would a sufficient assumption and I don't know if that's the correct way to do it.

[@therealsherminator]

On Necessary Assumption questions, some correct answers (~45%) will work by linking the argument together. Treat them the same as Sufficient Assumption questions, but be careful that the link provided doesn't go too far. Usually, the correct answer is both sufficient and necessary in these cases. For the rest of the Necessary Assumption questions (~55%), the correct answer will defend the argument from something that would destroy the argument's reasoning. This will be quite different from linking in that the factor being ruled out may seem out of scope since it was never mentioned in the argument. But it's relevant to the argument, so it should have been considered.

[@kamacazi9639]

So i have two ways which I approach these question types. 1. Necessary Assumptions: Sometimes I do link the conditionals together in an if/then relationship but based on the wording of the question linkage would not be required. If the question doesn’t have any conditional language then most likely you have to defend the idea the question is concluding as being necessary. The answer would defend the idea as the only idea that can occur. Sufficient Assumptions You can also link the conditionals like you would do with necessary assumptions; which is usually the only way you can answer this type of question. There is no idea to defend like the necessary assumption. So, both require linkages however necessary assumptions you can also defend an idea to get the answer which isn’t available for sufficient assumptions.

[@WaisNoah]

Hi, this was very very helpful! Do you have any videos on complex questions that require long conditional chains?

[@LSATLab]

We're only allowed to publish problems from June 2007, test 65, and test 71, so none of those Suff Assump questions happen to be long chain ones. You might get some of what you're looking for in the Conditional Logic video, though: kzbin.info/www/bejne/oJann6yhhNemrbs

[@WaisNoah]

@@LSATLab I see, thank you anyway for your prompt response. You are fantastic!

[@abandonallhope.1040]

For the last question, is answer choice C both a necessary and sufficient assumption? Because if it is NOT true that all of the aluminum is recovered when cans are recycled, wouldn't that destroy the argument's conclusion?

[@LSATLab]

Correct, that one would be both sufficient and necessary. Since this argument is so mathematical in nature, it all boils down to that one idea, so it's both needed and all that's needed. :)

[@lraoux]

Make sure not to look for an assumption that is already being made in the stimulus, but rather an assumption that, if made, needs to guarantee the conclusion. In other words, don’t mistake these for necessary assumption questions.

[@riyakapoor3218]

Lsat india is on 14June please post more

[@anirbanmukherjee5240]

2007, S2, Q6: answer choice A is not a negation. Question stem gives us executive board -> undergraduate + no felony. This is because felony -> no board, so the contrapositive combined with the first condition gives us that. Option A specialises this condition to board -> masters + no felony. This is because eligibility conditions are necessary conditions. Ie it’s not no felony -> board as shown in the visual but rather board -> no felony. Eligibility does not imply board membership. It simply means this condition must be present for the board members. Of course it could also be that there are multiple alternative eligibility criteria in which case it is not even a necessary condition but regardless it’s not a sufficient condition, and so not a negation.

[@anirbanmukherjee5240]

In fact, the argument for why option B is correct, interprets the word eligible as leading to a necessary condition.

[@celiamyers1387]

In question 6, how come the missing link isn't about the felony conviction? I'm not sure I understand the negation of answer choice (D).

[@abigaildossantos9576]

same

[@jakhongirabdurakhmonov7876]

There is no relationship here. But if we create it as per Conditional Reasoning Rules we cannot have sufficient condition even there is necessary condition since there may be some other requirements.

[@nuaxm2k92]

If a question stem says, .."which one of the following, if true, most seriously calls into question.." would it be a sufficient assumption question?

[@LSATLab]

That would be a weaken question :)

[@nuaxm2k92]

LSAT Lab oh okay, “calls into question” thank you !!!

[@noamchomsky729]

[@martini87c]

is there a faster way to analyze these types of questions and find the answer because come LSAT exam you have 35 minutes for the whole section so there isn't that much time to go through all of this .....

[@LSATLab]

The pace and depth of a lesson aren't meant to emulate the pace of actually doing the problem. In a lesson, you're trying to slowly introduce ideas to people and given them ample time to process what they're hearing. If we explained them at the speed we do them, it would be incredibly hard for people to follow along. :) Actually doing problems under timed conditions (better than 99% of other LSAT test takers, if we're aiming for 172+) takes an insane amount of practice. To be better than almost everybody at this test, you have to take these processes, make sure you understand them, and then rinse and repeat them so often that you develop automaticity for many parts of the process. You'll also sharpen your visual faculties, when it comes to indicator words such as "necessary / no / thus / since", so that you're able to find the functional details you need more quickly. And you have to become a really high level reader (able to process lots of language quickly), in order to do better than 99% of other LSAT test takers. The 35 minute time limit is deliberately cruel and insufficient. They're intending for most of us to *not* have enough time, so that the few people who CAN process (or learn to process) this material that quickly will be able to get higher scores than people who could answer the questions correctly but not that quickly. If they only wanted to test the accuracy of our thinking, they'd provide a more generous time limit. So, in short, the answer to your question "is there a faster way" is "Yes, it comes through tons of practice". But when it comes to Sufficient Assumption specifically, a lot of problems have a shortcut you might call the "I Need a Rule That Proves the Conclusion" shortcut. In that first problem, we're trying to prove that "Murray can't be accepted for the position of EA". To do so, we need facts about Murray, and we need a rule that says "If X, then can't be accepted for the position of EA". The argument's premises provide facts about Murray, but they never provide a rule that says, "If X, then can't be accepted for the position of EA". We know then that the correct answer has to supply that type of premise. The only answer that provides a rule like, "If X, then can't be accepted for the position of EA" is the correct answer B. It says, "If you're not eligible for appointment to the Exec Board, then you can't be accepted for the position of EA". That shortcut won't always lead to one answer, but it will usually quickly kill of at least a couple.

[@martini87c]

@@LSATLab hi thank you so much for this reply I understand what you are saying I think practice it the key. I’m the kind of person who wants to see the answer immediately and solve it but I don’t think it’s that kind of test. Thank you kindly 🙂

[@RachelTprouse]

​@@martini87c hey! there is a faster way (at least for me). i start by finding the conclusion and premise of the argument, try to figure out if any assumptions are made, then look for the answer that COMPLETES the argument. not just strengthen the argument, but makes it completely VALID. a way to double check if it's really a SA instead of NA, is to negate the answer choice you picked - if you negate it and the argument still stands, it's a SA (be careful of irrelevant/out of scope trap answers). if you negate it and the argument falls apart/becomes invalid, it's a NA. hope this helps

[@martini87c]

@@RachelTprouse hi thank you for this reply I appreciate it. It does help and I’ll apply this method too to these questions. Thank you ☺️☺️☺️

[@jorgetorresbenitez3027]

I dislike this question types more than any question in the LSAT. Even worse than parallel flaw.