Tips for Quickly Eliminating Answer Choices (PR, Strengthen, Assumptions)

Sarah889

Hey All,

Over the past few months, since I began my LSAT journey, I've accumulated a few tips on how to quickly eliminate answer choices for Parallel Reasoning, Strengthen and basically any Assumption question. I was recently BRing with another 7Sager the other night and I was trying to explain these strategies, but I was hesitant to do so because I am not 100% confident that they work every single time. Meaning, they haven't been affirmed to me by someone who knows what they're doing, so there's definitely a chance I could be wrong in my approach. I was hoping to get a few more experienced LSATers/7Sagers to take a look at the two strategies below and let me know if these are reliable or if they can see a blind spot that I am not seeing. I can't recall exactly where these strategies derived from, but I have been using them for a while.

1) Strengthen and any Assumption Questions
-Whenever the conclusion mentions anything (whether it is a new attribute, new agent, new criteria, etc.) that is not previously mentioned the premises, the correct answer will always mention that new component. You can automatically eliminate any answer choice that does not mention this new component.

This has made it easy for me to sometimes eliminate 2 to 3 answer choices in seconds without fully reading them. This obviously helps you save time, but it also helps you avoid trap answer choices that try and play on your biases. In the spirit of giving pre- PT35 (or is it 36) examples, see below.

PT32.S1.Q5 (sufficient assumption question): The new element introduced in the conclusion is economic crises; therefore, the answer choice would have to include this element. Know this, we can immediately eliminate D (discusses good economic decisions, but does not touch economic crises) and E (is focused on the small elite. This does nothing to link our conclusion to our premises). You then only have A, B and C to consider.

PT33.S3.Q4 (strengthen question): The new element introduced in the conclusion is cost-effectiveness. Looking for this in the answer choices, we can eliminate B (has nothing to do with the cost of anything), D (which, yes, it talks about funding but we are not concerned with how much funding is currently being contributed. We are concerned with cost-effectiveness), and E (also mentions nothing about costs or their effectiveness). We are then left with only answer choices A and C.

This doesn't happen all the time, but it happens often. And it's wonderful.

2) Parallel Reasoning

I want to preface this by disclosing that I have not yet been through JY's lesson on how to approach Parallel reasoning questions. I am still working my way through, so I apologize if he already does this/advises not to do this. Also, this doesn't work for flaw questions. I approach flaw questions differently than parallel reasoning (again, someone correct me if I'm wrong here) because I am looking for something very specific with flaw questions--namely, a logical fallacy. For parallel reasoning, I am literally only looking at the structure, whether or not it is a valid argument. So this only works for parallel reasoning.

The first thing I do with parallel reasoning is examine the conclusion. I translate that into logic and I scan the answer choices for any answer choice that does not have a conclusion that matches the stimulus. I immediately eliminate those answer choices. My theory is that, if we are looking for a parallel structure, the conclusion absolutely has to be parallel. If the stimulus' conclusion is something like "All X's are Ys" and there are answer choices that say "Some A's are B's" or "All A's are some B's," then I just cross them out before I go any further. This usually eliminates 2 or 3 and it cuts down on a lot of reading. Once I'm left with 2 or 3 options, I then examine the remaining answer choices. See below for some examples.

PT33.S1.Q.23 The conclusion is "Any traveler who flies from B to L cannot avoid flying to X." The first thing I note is that this is a universal statement. I would write: "TBL --> X." I would then quickly scan the answer choices for their conclusions and automatically eliminate A (this conclusion is not universal because it says that the inference is likely, not necessary. Our conclusion is absolute), D (this doesn't even give us a conditional at all), and E (again, this is an existential conclusion. Our conclusion is universal). We are then left with B and C, which each have universal conclusions:
B-- Y --> PW
C-- IMP --> PM
I would then further evaluate the premises of the remaining 2.

PT34.S2.Q6. The conclusion is "The notion that one might be justified in behaving irrationally in the service of a sufficiently worthy end is incoherent." So, I would write that out as "N is I" (I wrote it this way because there was no obvious logic indicators, but you could also write "N --> I") and I would scan the answer choices for conclusions not matching this. I can eliminate A (because it is prescriptive. The conclusion is "RL ought not to CC." Our definition is making a universally descriptive claim) and E (also prescriptive. Our conclusion is saying nothing about what someone ought to do.) So we are left with B, C, and D which all have conclusions that can be translated "A is B."
B-- Spilling a glass of water is not accidental.
C-- Living the good life is happy (not unhappy).
D-- Self diagnoses are not performed by doctors.
I would then further evaluate the premises of each of the remaining 3.


Again, I am looking for thoughts, corrections, affirmations...whatever you more experienced LSATers can give me on these strategies. Thanks in advance.

Cant Get Right

@bswise2 , thanks for posting! This is really comprehensive and well thought out.

So, for sufficient assumption questions, that rule is going to be absolute. It is impossible to construct a correct answer choice that violates this rule.

For strengthen questions, I can conceive of how they might bypass it. The argument would remain incredibly weak, of course, but that level of subtlety is exactly what makes strengthen (and conversely, weaken) questions the hardest question types on the test. This will usually hold true, but it isn't a logical necessity the way it is with SA questions.

With parallel reasoning, I can't think of having seen any exceptions to this. I'm not sure it's possible to create an exception. So I think you're safe here. If they do throw you one that somehow violates this, I wouldn't even worry about it. At that point, my primary objective is to miss it without wasting any more time than I have to, lol.

stepharizona

Thanks for sharing!

Agree the conclusion in PR is a great first test, I had completely forgotten about it until a week ago during a review session. I also was reminded of a "rule" recently that if a PR has things like Most, Some, Many the correct answer can't be in absolutes. All... Every... Everytime... I used the be really good at PR and then got really bad... but I stopped using these tools... I am back to using them and success rate has been good so far. Not sure why I stopped doing them. Anyone want to add input into the "Some" doesn't switch to "All"

I think the problem with studying so long, is often the tips we learned at the beginning get lost along the way...

attorneysomerville

Nice insights!

GRACIEEEE

Thank you for sharing!
I will try your parallel questions method; they are definitely my time trappers.

tanes256

Thx @bswise2! I'm eager to try your PR strategy! Sorry to hijack your post but I was going to post something similar a few days ago. Hope you don't mind me adding here. Just as above, I would love any feedback.

Sufficient Assumption: do you guys see anything wrong with negating the conclusion? When the conclusion is negated the correct AC MUST be false because a SA that would allow the conclusion to be true, when negated, MUST be false. I like to think of this as a test to check your answer just as we use for NA questions.

Weaken:
1. AC using "some" does not weaken an argument. Strong language like all, only, the most, etc. will weaken or strengthen an argument.

2. Try to find a NA in the stimulus. This is often what the correct AC will target.

3. I still have trouble prephrasing. I've just gone so long without doing it. Someone told me to prephrase weaken questions with "Given that (premise) is true,"... or "How can we argue for (the anti-conclusion?" I kind of get it but my inexperience with prephrasing may also be hindering me. Anybody care to elaborate or give their take on prephrasing?

Strengthen: Correct AC should trigger the conclusion.

Necessary Assumption:
1. correct AC can't be a conditional chain because it will contain an assumption; thus not MBT. Most conditional statements will be wrong because they're too extreme.

2. correct AC will strengthen the argument and destroy the argument if negated.

3. New term: new term introduced in conclusion means that author must be assuming that x in the premise is equivalent to y in the conclusion. We can counter and show that x is not equivalent to y.

Please feel free to chop up anything that you guys have doubts about. I don't want to get comfortable with any of this if it's wrong or just simply not reliable. TIA!

jknauf

Hey @tanes256

The problem with negating the conclusion in sufficient assumptions is the sufficient assumption is something that's enough to guarantee the conclusion but it's not required to do so. The negation technique should be used for Necessary Assumption questions. In NA questions, if you negate the answer choice, our conclusion can no longer hold true due to the necessary assumption being negated. Let me try and explain further,

So if we have a conclusion that says, @jknauf will drive to New York in 4 hours, we have this conditional conclusion

JDNY4

Now, what is a sufficient assumption answer choice we could see for a question like this? How about @jknauf has a car that gets him there in 3.5 hours instead of 4 -

C3.5 ----> JDNY4

Well that is certainly helpful! But, is that necessary to reach our conclusion? Does it need to be true that I drive a car that gets me to New York in 3.5 hours instead of 4? No, but it is sufficient to guarantee that I do get there in 4 hours.

So if I negate the conclusion, must it be false that I don't have a car that gets me there in 3.5 hours? No, it could be that I have a car that gets me there in 3.5 hours but I got stuck at a toll booth or something.


So now for our NA technique, lets say the necessary assumption is, @jknauf has access to any vehicle which will get him there in 4 hours

JDNY4 ---> AV4H

If we negate our assumption, /AV4H, our argument completely falls apart.

/JDNY4 <--------- /AV4H

If I don't have access to any vehicle that can get me there in 4 hours, it's not possible for me to drive there in 4 hours. So a necessary assumption we must make in order conclude @jknauf can drive to New York in 4 hours is that @jknauf has access to a vehicle which can get me there in 4 hours.

tanes256

@jknauf ok this is an example of my thoughts on negating the conclusion. Let me know if I just made up something, Lol!

A + (A+B) --> B

When the conclusion is negated;

A + (A+B) ---> /B

When the SA (A+B) is accepted then the conclusion must be true. Here we can see that the SA (A+B) doesn't get us to the negated conclusion (/B). Any answer choice that would allow the negated conclusion (/B) to be true, is incorrect. The correct answer choice (A+B) must be false when the conclusion is negated.

jknauf

Hey @tanes256

That does sound plausible. Does this happen often in the AC's? Is there many answer choices which would give us the negated conclusion?

tanes256

@jknauf i just had one today in PT 55. I think it's section 3. Not really sure but it's whatever the 2nd LR section is. I don't have the test in front of me right now to give you the question number but it was something about someone witnessed an assault and could recognize the assailant but couldn't recognize the famous client. I recognized the "should" in the concludion but nowhere else in the stimulus so I knew the AC would include "should". This doesn't happen often but I did recognize it. That tidbit left me with 2 options and I was able to use the method I stated above to get the correct AC. I haven't been using this long but I wanted to throw it out here to see if I was wrong before completely implementing it if I'm stuck. I knew the correct AC on this one but I used it to see if it worked and it did. I can't think of any others off the top of my head. Hopefully a mentor can say whether it's a go or not.

Edit:
PT 55-3-10

jknauf

@tanes256

Well if the goal of a sufficient assumption is to bridge the gap between the premises and the conclusion and the bridge takes us to another location (Negated Conclusion) then it must be true that AC is incorrect. So I think the logic checks out. The thing to keep in mind however is an incorrect answer choice can also take you somewhere else which isn't the negated conclusion. If you think this strategy can be fruitful given the time constraints then definitely use it. @tanes256 Good job

tanes256

@jknauf said:
The thing to keep in mind however is an incorrect answer choice can also take you somewhere else which isn't the negated conclusion.

I see what you're saying. This is only after all else has failed.