Parallel Reasoning Questions in LSAT Logical Reasoning

Many LSAT students find that Parallel Reasoning questions take more time than any other logical reasoning question on the LSAT. These questions have more text, take more time to read and often more time to answer correctly. Each answer choice in a parallel reasoning question is often as long as the argument itself. Watch your clock and if you find that Parallel Reasoning questions are taking you much longer than the other questions then skip them and come back if you have time once you have done all the other questions. Learn more about Skipping LSAT Questions here.

In Parallel Reasoning questions you are given an argument and asked to identify the answer choice that most closely parallels the argument. This means the two arguments will have the same structure but different concepts and ideas discussed in them. A very simple example is the following:

Argument: All sharks have fins and all dolphins have fins therefore they are similar.

Answer choices:

(A) Sharks and dolphins are similar, however, they have many differences.

(B) All sharks have teeth, dolphins are similar to sharks therefore they must have teeth.

(C) Bats and eagles must be similar because every bat has wings and so does every eagle.

(D) All dogs have eyes and all cats have eyes.

(E) Some rats have fur and all mammals have fur, therefore, rats are mammals.

Which is the correct answer choice? In order to solve parallel reasoning questions you can ignore the specifics and look only to the general structure. So ignore the terms like dolphins, fins, sharks, rats and bats. Break it down to a basic structure and then look for the same in the answer choices.

The structure of the argument “All sharks have fins and all dolphins have fins therefore they are similar.” can be broken down as follows:

ALL of entity X have attribute Y and ALL of entity Z have attribute Y. Therefore X and Z are similar.

You can also break it down into a numbered list of elements that must be included in the parallel argument:

1. ALL of entity X have attribute Y

2. ALL of entity Z have attribute Y

3. Therefore X and Z are similar

If not all of these elements are present in the answer choice then it cannot be right.

Look for this same structure in the answers.

(A) This answer says they two entities are similar but have differences. It does not include the fact that they share some attribute.

(B) Does not give us the premise that both entities share the same trait. It is instead used as a conclusion based on the premise that the two entities are similar.

(C) This is the correct answer choice. It used different specifics, bats, eagles and wings instead of dolphins, sharks and fins, however, it has the same basic structure. You have two entities that share the same trait and therefore must be similar. Note that they do change the order of the argument, this is okay as long as the required elements are present.

Element 3: Bats and eagles must be similar because

Element 1: every bat has wings

Element 2: and so does every eagle.

(D)This is missing our third element: Therefore X and Z are similar

(E) There are a number of differences here including that not all the given entities are said to have the given flaw, only some. To be parallel in reasoning we must have all entities with the given trait.

A good way to approach Parallel Reasoning questions is the quickly write down a list of the required elements as we did above. Do this in short hand and be quick. Then check each answer choice to see if it has all the required elements.

Question Stems:

Take a look at the following actual LSAT question stems for Parallel Reasoning questions. Notice that they are all quite similar and all ask you to find the passage below that most closely parallels the argument above.

Which one of the following arguments is most similar in its reasoning to the argument above? (June 2007 LSAT Section II Question 12)

The flawed reasoning exhibited by the argument above is most similar to that exhibited by which one of the following arguments? (June 2007 LSAT Section III Question 20)

Which one of the following uses flawed reasoning that most closely resembles the flawed reasoning used in the argument above? (June 2007 LSAT Section II Question 2)

Each of these question stems is quite similar and easy to identify as they look for the arguments that are similar to the argument given. Key words to look for in the parallel reasoning question stems include:

• parallel reasoning
• closely parallels
• closely resembles
• most similar

Flawed reasoning – notice that some of the parallel reasoning questions will ask you to find the answer that uses the most similar or parallel “FLAWED” reasoning. The only difference with these questions is that the reasoning in the correct answer choice and the argument is flawed. The method for solving flawed parallel reasoning questions is no different then solving regular parallel reasoning questions. We are simply looking to find the parallel reasoning, if there happens to be a flaw in that reasoning it will not affect our approach to the question.

For example the following statement has flawed reasoning:

Some cats have hair, some dogs have fur, therefore some dogs are cats.

There is an obvious flaw in this reasoning but it does not affect our approach. Simply identify the structure of the argument and then find the answer with the same structure. Our structure here is:

1. Some of entity C have trait H

2. Some of entity D have trait H

3. Therefore some of D are C

A statement with similar flawed reasoning is:

Some bad drivers get angry easily, some parents get angry easily, therefore some parents are bad drivers.

Note that this argument makes a lot more sense than the one about cats and dogs but the flaw is the same. Based solely on the information given in this statement we cannot conclude that same parents are bad drivers. Even though it is true, the argument that brings us to that conclusion is flawed. But more importantly it is flawed with the same structure as our original argument so it could be our correct answer for a parallel reasoning question.

Right Answer Choices:

The right answer choices in a parallel reasoning question have the following attributes:

• they follow the same structure of the original argument
• they can be in a different order as long as all elements are included
• they can, and most often do, refer to different entities or specifics than the original argument

Wrong Answer Choices:

Some common things to look for in spotting wrong answer choices in parallel reasoning questions include:

• the specifics are the same but the structure is different
• one or more elements from the structure are missing
• additional elements are added to the argument structure
• the elements are almost all there and are in the same order but with just one element missing

If you have difficulty with the parallel reasoning questions a good approach is to use short hand to note the structure of the argument. Then as you look at each answer choice check off each element in your short hand structure, if you find that one is missing then that is a wrong answer and you can move on. The correct answer will have all of your elements included.

Sample LSAT Questions:

The following are some example parallel reasoning questions that have appeared on actual LSATs in the past. Due to copyright laws we cannot reproduce the full questions here but you can access these LSAT questions for free here. A good approach is to download the free June 2007 Actual LSAT test and try these questions yourself and then come back here for the explanations. The questions we will review here are all from the June 2007 LSAT and include:

• Section II Question 2
• Section II Question 12
• Section III Question 20

Parallel Reasoning Sample LSAT Question 1: (June 2007 LSAT Section II Question 2)

The argument given is this question is as follows:

All Labrador retrievers bark a great deal. All Saint Bernards bark infrequently. Each of Rosa’s dogs is a cross between a Labrador retriever and a Saint Bernard. Therefore, Rosa’s dogs are moderate barkers. (June 2007 LSAT Section II Question 2)

This is a relatively easy parallel reasoning question. Note that it includes flawed parallel reasoning but the question is still easy when compared to other parallel reasoning questions. The flawed reasoning aspect seldom increases the difficulty.

As you read the argument, make short hand notes representing the structure of the argument. Remember that specifics like Labradors and Barking are not important, it is the structure that counts. Try to keep it simple and short. The structure here is as follows:

1. All L = B lots (all Labradors Bark Lots)
2. All S = B little
3. X are L/S Therefore X = B moderate

The structure could also be presented as:

1. All of one entity have strong trait
2. All of a second entity have a weak trait
3. A specific entity that is partway between the entity one and two must therefore have a moderate trait

You can express your structures in many different ways, the key here is to ensure that you understand it, that it is quick and easy to write down and that it includes all elements of the argument structure.

Next look at each answer choice and find the one that matches each of the three elements listed above.

Answer Choices:

(A) Has 1. but when we come to 2. we have “Some students” not “all students” as would be required to match our structure. Also the last element is mixed up and not the same as the structure we are looking to parallel. As soon as you determine that the answer choice is missing elements or does not match the structure, move on. However, for extra practice let’s break down the structure of this answer choice. The structure of this answer choice could be presented as follows:

1. All DS = G good
2. Some Not DS = G good
3. J is Mid-DS therefore J = G somewhat/moderate

(B) This is the correct answer. It matches each of the elements in our structure above. We have and entity (type A) with a strong trait (toxic) an entity (type B) with a weak trait (not toxic) and finally a specific example that is part of both entities which must therefore have a moderate trait.

(C) This one is very close but not quite right. We have our first two elements and half of our third element, however, the conclusion is that they live either in one or the other place as opposed to being in between the two places (similar to being in between a frequent and infrequent barker in the argument). If this answer concluded that they live in between the two counties it would be closer to the correct answer.

(D) This comes close to satisfying our elements but what we are looking for is entities that have a strong and weak showing of the same trait (e.g. barking) as opposed to having two totally different traits (e.g. calculus and shorthand).

(E) This has the first two elements satisfied but then does not match the third element of our structure. If it had ended with “Both Connie and Kenisha helped make this dress therefore it is moderately well made” it would be a much better answer choice.

Parallel Reasoning Sample LSAT Question 2: (June 2007 LSAT Section II Question 12)

The argument given is this question is as follows:

Suppose I have promised to keep a confidence and someone asks me a question that I cannot answer truthfully without thereby breaking the promise. Obviously, I cannot both keep and break the same promise. Therefore, one cannot be obliged both to answer all questions truthfully and to keep all promises. (June 2007 LSAT Section II Question 12)

This is one of the more difficult parallel reasoning questions. First we want to break this argument down into its basic elements or structure leaving out the specifics like promises, truth and confidence.

Suppose I have promised to keep a confidence

1. There is an Action A

and someone asks me a question that I cannot answer truthfully without thereby breaking the promise. Obviously, I cannot both keep and break the same promise.

2. There is an Action B

3. If you do Action B you cannot do Action A

Therefore, one cannot be obliged both to answer all questions truthfully and to keep all promises.

4. Therefore you cannot do B and A

So our argument structure looks like this:

1. Action A
2. Action B
3. If Action B then cannot do Action A
4. Therefore cannot have B and A

Now we apply this to each answer choice. For each answer choice put a check mark or “X” next to each element. If you have an “X” it cannot be the right answer choice.

Answer Choices:

(A) This is the correct answer. It has each of the elements in the argument structure. Action A is saying whatever you want, Action B is being civil. If you are civil you cannot always say what you want, which satisfies element #3. Therefore you cannot say what you want and be civil, which satisfies element #4.

(B) The structure of this argument does not match at all. It goes as follows:

1. Some of entity P (politicians) can get result V (popularity) only through action E (promises)
2. However E means D (deceive people)
3. The only way for some P to V is D
4. Every P needs V
5. Some P will D

None of the elements here really match the argument given in this question so this answer choice is wrong. Note that you do not have to take the time to break down each answer choice like this, we only break it down here to give you extra practice breaking down arguments. Instead, for each answer choice just check to see if the elements in your structure for the main argument match, no need to figure out what the actual elements in each answer choice are.

(C) This answer choice is missing all the elements except for maybe having an action A and action B.

1. If A (effort) then maybe M (not on own merits)
2. If not A then maybe S (not serious)
3. A or not A risks C (criticism)

(D)

The structure for this answer choice is as follows:

1. If entity B (business) have trait L (creditors with legit claims)
2. and B has trait R (resources)
3. Then B must take action P (pay debts)
4. If (element 3. exists) then result F (court forces to pay)
5. But Not F so either Not L or Not R

This could also be expressed as:

1. If trait L and traid R then P
2. If P then F
3. No F so either No L or No R

Remember that we are breaking down the structure of each answer choice for your practice here but on the actual test you do not need to do this, just check if the elements from the main argument are present. Answer choice (D) has no matching elements with the main argument structure.

(E) This answer choice may match the first two elements of having and Action A and Acton B but does not match with the rest of the structure.

The structure for this answer choice is as follows:

1. If action E then either N or O
2. Both N and O = C (cost)
3. Cannot C so No E

Parallel Reasoning Sample LSAT Question 3: (June 2007 LSAT Section III Question 20)

The argument given is this question is as follows:

We should accept the proposal to demolish the old train station, because the local historical society, which vehemently opposes this, is dominated by people who have no commitment to long-term economic well-being. Preserving old buildings creates an impediment to new development, which is critical to economic health. (June 2007 LSAT Section III Question 20)

The structure of this argument can be broken down as follows:

1. Accept conclusion
2. despite people opposing it
3. because the people opposing the conclusion have self interest opposed to conclusion

Now look for the answer choice that matches this reasoning structure. Note that while there is a flaw in the argument it should have little effect on your analysis of the question and answer choices.

Answer Choices:

(A) This answer choice does have the first two elements but does not include the element of criticising the opposition for their beliefs or interests.

(B) This choice includes the first element but not the last two.

(C) This is the correct answer. It may not seem clear at first but it does match the argument structure. We have 1. the conclusion they urge you to accept (cut your hair no more than once a month), 2. despite the opposition (beauticians) and 3. because the opposition has certain self interests opposed to the conclusion (they make more money)

(D) This matches the first and perhaps the second elements but not the third.

(E) This matches only the first element.

Extra practice and homework: For extra practice take articles from the newspaper or Economist Magazine and break them down into their structural elements.

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