How To Master LR | LSAT Logical Reasoning

Summary

This LSAT Lab lesson focuses on mastering the Logical Reasoning section of the LSAT, which constitutes half of the total score. The video explains key strategies for approaching different question types, such as assumption, function, and inference-based questions. It also covers how to identify flaws in arguments, understand reasoning structures, and eliminate trap answers. By breaking down the difficulty levels of questions, the lesson provides valuable tips on how to approach each section, helping students develop intuition and analytical skills to excel in the Logical Reasoning portion of the exam.

Takeaways

• 📝 The logical reasoning section is crucial, accounting for half of the total LSAT score.
• 📊 There are three main question families in logical reasoning: Assumption (64%), Function (19%), and Inference (24%).
• 🔍 The LSAT focuses on argument validity, not soundness, meaning it only tests whether conclusions logically follow from evidence, not if the evidence is true.
• 🔑 To succeed in the assumption family, students must identify gaps in the argument’s reasoning and evaluate its validity.
• 🛠️ The function family of questions tests your ability to analyze the role of statements within an argument, understanding how they contribute to the overall logic.
• 📖 Inference questions challenge students to deduce what can be inferred from given statements, often without arguments.
• 📈 Logical reasoning sections have a varied difficulty curve, with questions becoming harder in later sections, rewarding students who get through the tougher parts.
• 🧠 Intuition plays a large role in the earlier parts of the section, while more complex reasoning is needed as the difficulty increases.
• ⚠️ Trap answers fall into three categories: scope, logic, and degree. Mastering the ability to spot these traps is key to success.
• 🔗 Understanding reasoning structures—conditional logic, causality, and comparison—is crucial for tackling difficult questions in the last third of the section.

Q & A

What is the importance of the Logical Reasoning section in the LSAT?

The Logical Reasoning section is crucial because it constitutes half of the total LSAT score, with two out of the four scored sections being Logical Reasoning sections.

What are the three main families of question types in Logical Reasoning?

The three main families of question types are: the Assumption family (64% of questions), the Function family (19% of questions), and the Inference family (24% of questions).

What is the primary focus of questions in the Assumption family?

The Assumption family questions focus on evaluating arguments by identifying the gap or flaw in the reasoning, questioning whether the conclusion logically follows from the evidence.

What is the role of the Function family of questions?

The Function family of questions measures the ability to abstract reasoning and understand the purpose or role of different parts of an argument, essentially analyzing how claims function within the argument.

How does the Inference family differ from the other two families?

The Inference family asks test-takers to figure out what can be logically deduced based on a set of statements, instead of analyzing arguments. These questions focus on what can be inferred from the information provided.

What reasoning structure is the most common in Logical Reasoning questions?

Conditional logic is the most common reasoning structure, playing a role in 54% of all Logical Reasoning questions.

How does the LSAT typically increase the difficulty level in Logical Reasoning questions?

The difficulty level increases by providing more tempting but wrong answer choices, presenting more complex arguments, and introducing unfamiliar topics that make it harder to rely on intuition.

What are some common trap answer patterns to be aware of in Logical Reasoning questions?

Common trap answer patterns include scope shifts, logical reversals, and changes in degree. Understanding these traps is essential to eliminate wrong but tempting answer choices.

How should students approach the first third of a Logical Reasoning section?

In the first third of the section, students should primarily rely on intuition, using real-world knowledge to quickly identify gaps in reasoning and answer questions without overanalyzing.

Why is understanding reasoning structures important for the harder questions in Logical Reasoning?

In the more difficult questions, reasoning structures like conditional logic, causality, and comparison help identify gaps in reasoning more systematically, providing a clearer path to the correct answer.

Outlines

00:00

📚 Introduction to LSAT Logical Reasoning

In this lesson, Matt from LSAT Lab introduces the importance of mastering the Logical Reasoning section, which comprises half of the total score on the LSAT. He explains the structure of the section, including five multiple-choice answers per question and an average of 25 questions per section. Matt defines key components like the stimulus and question stem, emphasizing the importance of understanding these to organize one’s work around different question types. He introduces the Assumption family as one of the major categories of Logical Reasoning questions, focusing on identifying flaws in arguments.

05:00

📈 Difficulty Levels and Question Trends in Logical Reasoning

This section explores the varying difficulty levels within the Logical Reasoning section of the LSAT. Matt presents a real example from LSAT Prep Test 72, showing how the difficulty fluctuates. He compares different sections, like Prep Test 76, which presents a steeper difficulty curve. By analyzing multiple sections, Matt highlights a consistent challenge-reward pattern in the LSAT. This pattern rewards students who make it through the entire section, especially after question 12 and beyond question 21. The section is divided into three parts: the easiest first third, a more challenging middle, and the hardest final third.

10:01

🧠 Intuitive Thinking for Tackling Early Questions

Matt advises using intuitive thinking to approach the first third of the Logical Reasoning section. He emphasizes avoiding over-analysis and relying on real-world experiences to counter arguments. He provides an example of an argument about blue cars being the fastest and how assumptions influence reasoning. The ability to draw on everyday knowledge helps in quickly identifying flaws. As the section progresses, the difficulty increases, requiring more critical thinking. In the later part of the section, more tempting but incorrect answers appear, demanding a sharper focus on eliminating traps.

15:03

🎯 Identifying Trap Answers in the Final Third

This segment delves into the challenge of eliminating trap answers as questions become more difficult toward the end of the section. Matt outlines how similar-looking answers, like those using 'if' in different places, can reverse relationships in arguments. Recognizing traps based on scope, logic, and degree is crucial. He introduces three main categories of traps: reversal, scope, and logic-based errors. Identifying these patterns is key to making eliminations, especially when facing complex arguments with topics unfamiliar to most test-takers, such as fossils or obscure theories.

🔗 Understanding Key Reasoning Structures

Matt emphasizes the importance of understanding reasoning structures to master the hardest questions in Logical Reasoning. He introduces three critical structures: conditional logic, causation, and comparison. Conditional logic involves 'if-then' relationships, with 54% of questions depending on this concept. Causation, which appears in 34% of questions, is more about a direct cause-effect relationship. Comparison, the most frequently tested structure at 65%, involves understanding how two items or situations compare either in time or effectiveness. Mastering these structures is vital for success in identifying gaps in arguments.

🎓 Final Tips for Mastering Logical Reasoning

In this conclusion, Matt summarizes three keys to mastering Logical Reasoning: understanding argument structures, using keywords to identify reasoning structures, and recognizing trap answer patterns. He emphasizes the importance of recognizing conclusions, evidence, and opposing viewpoints to structure arguments effectively. The use of keywords will aid in anticipating the gaps in reasoning, while trap answers will help eliminate wrong choices. The goal is to develop a strategic mindset to approach the section and answer both easy and challenging questions successfully.

Keywords

💡Logical Reasoning Section

The Logical Reasoning section is a critical component of the LSAT exam, making up half of the total score. It tests a student's ability to analyze and evaluate arguments. Each Logical Reasoning section consists of 25 questions and lasts 35 minutes. The video emphasizes mastering this section by understanding its question types, difficulty patterns, and how to identify trap answers.

💡Stimulus

The stimulus is the initial paragraph in a Logical Reasoning question that provides the information or argument upon which the question is based. This could be a set of statements or a complete argument. Understanding the stimulus is essential, as it sets the context for the entire question and determines what needs to be analyzed in the subsequent question stem and answer choices.

💡Question Stem

The question stem is the part of a Logical Reasoning question that tells the test-taker what needs to be done. It provides the task or instruction, such as identifying the main point, finding the assumption, or evaluating the argument. Knowing the question stem is crucial because it helps in organizing one’s approach to solving the question effectively, as it guides what kind of reasoning or analysis is required.

💡Assumption Family

The Assumption Family refers to a group of Logical Reasoning questions that test a student's ability to identify gaps in arguments. Making up 64% of the Logical Reasoning questions, this family includes question types such as Assumption, Strengthen, and Weaken. Success in this family depends on the ability to evaluate arguments by identifying flaws or assumptions that connect evidence to the conclusion.

💡Validity

Validity in the context of the LSAT means that the evidence in an argument guarantees the conclusion. The LSAT focuses on validity, not soundness, which means students should accept the given evidence and only analyze whether the evidence logically supports the conclusion. This understanding helps test-takers focus on evaluating the logical structure rather than the truth of the statements presented.

💡Trap Answers

Trap answers are incorrect choices designed to look appealing or similar to the correct answer, making the question more challenging. They are created using patterns related to scope, logic, and degree, and often appear similar to correct answers but differ in subtle ways. Being able to identify and eliminate these trap answers is a key strategy in mastering the Logical Reasoning section.

💡Reasoning Structures

Reasoning structures are the logical frameworks used to build arguments, such as conditional logic, causation, and comparison. These structures help organize information and determine how different statements relate to each other. Understanding these structures is crucial for identifying gaps or flaws in complex arguments, especially in the more difficult questions in the Logical Reasoning section.

💡Conditional Logic

Conditional logic is a reasoning structure that uses 'if-then' relationships to link different statements. For example, 'If A, then B' means that A being true guarantees B. Conditional logic is present in 54% of Logical Reasoning questions and is used to establish necessary and sufficient conditions. Mastering this concept helps in solving many argument-based questions, particularly when dealing with chains of conditions.

💡Causal Reasoning

Causal reasoning establishes a cause-and-effect relationship between two events. Unlike conditional logic, which implies correlation, causation suggests a stronger relationship where one event is responsible for another. Causal reasoning is used in 34% of Logical Reasoning questions and is a common structure in arguments. Understanding causation helps identify when arguments mistakenly attribute causality, which is a frequent flaw.

💡Difficulty Curve

The difficulty curve describes how question difficulty varies throughout a Logical Reasoning section. The video notes that difficulty often increases in a 'challenge-reward' pattern, with easier questions in the beginning, a middle section of mixed difficulty, and the hardest questions at the end. Recognizing this pattern helps students manage their time and mental energy effectively, adjusting their approach as they progress through the section.

Highlights

The logical reasoning section is crucial as it accounts for half of the LSAT score, with two sections dedicated to it.

Each logical reasoning section consists of 25 questions, with 35 minutes allotted per section.

The three major question families in logical reasoning are Assumption, Function, and Inference, covering 64%, 19%, and 24% of the questions, respectively.

The LSAT emphasizes argument validity, not soundness. This means we don't question the truth of the evidence but whether it supports the conclusion.

In assumption family questions, identifying the gap in reasoning is key to success as every argument is flawed in terms of validity.

Function family questions require understanding the role or purpose of various components in an argument.

Inference family questions focus on determining what can logically be inferred from a set of statements rather than evaluating an argument.

LSAT logical reasoning sections have distinct difficulty curves, rewarding students at different stages, with easier questions at the beginning and the hardest towards the end.

The first third of the section is typically easier and should be approached with intuitive thinking and everyday real-world knowledge.

Trap answers fall into three categories: scope, logic, and degree. Identifying these traps helps eliminate tempting but incorrect answers.

As you progress through the section, reasoning structures such as conditional logic, causation, and comparison become vital in identifying gaps in arguments.

Conditional logic appears in 54% of logical reasoning questions, making it a critical reasoning structure to master.

Causal reasoning structures are present in 34% of questions and require understanding of cause-and-effect relationships.

Comparative reasoning structures are the most common, appearing in 65% of logical reasoning questions, involving comparisons of two entities.

Mastering logical reasoning involves understanding argument structure, using reasoning structures, and recognizing trap answer patterns.

Transcripts

[Music]

hi this is matt at LSAT lab and today's

lesson is on how to master the logical

reasoning section it's a really

important section type since there are

twice as many sections of logical

reasoning as any other section type in

today's lesson we're to cover the

following the role of the logical

reasoning section on the LSAT the

different kinds of question types you

should expect to face in the logical

reasoning section how they make

questions more or less difficult how to

use trap answers in order to eliminate

wrong answers and how to use reasoning

structures to better identify the gap in

the argument so let's get started like

every question on the LSAT and logical

reasoning there are five multiple-choice

answers for every question on average

there are 25 questions per section and

logical reasoning and each section is 35

minutes per section there are a total of

four sections that are scored on the

LSAT and two of them are logical

reasoning sections which makes logical

reasoning half of your total score

here's an actual question from the

logical reasoning section for now all we

want to do is identify the different

parts of the questions so that we have

the same vocabulary to talk about

different places in the question that

initial paragraph is called the stimulus

and it's the place where we get the

information on which we're going to act

whether it's a set of statements or an

argument they're gonna ask us a question

based on that initial stimulus then we

have the question stem and the question

stem is where we get our task the thing

that we need to accomplish in order to

get to the correct answer question stem

is very important because it helps us

organize our work we can organize our

study around the different question

types and those will give us information

both about what kinds of things to

expect in the stimulus and what kinds of

things to expect in the answer choices

we're always going to get five

multiple-choice answers and it's our job

to pick the one that best answers the

question so if we organize our work on

question types one thing we'll see is

that there are a lot of different kinds

of questions that they can ask and that

those questions or different question

types can be grouped according to these

three large families the first family is

the assumption family 64% of all logical

reasoning quest

are in assumption family these questions

measure our ability to evaluate

arguments and so what we'll be looking

for is the gap or problem with the

argument the flaw in his reasoning if we

can understand what's wrong with the

argument that will be the key to success

on all of these question types one thing

that we really want to be clear on when

when evaluating arguments is in how we

judge the argument and so there's a

concept of validity and another concept

of soundness in the LSAT doesn't care

about both of these it's really

important that we get clear what the art

what the LSAT is looking for so a valid

argument is one in which the evidence

proves the conclusion 100% guaranteed

and a sound argument is one in which the

evidence proves a conclusion but the

evidence is indeed true as well

the LSAT does not care about soundness

the LSAT only cares about validity and

what that means is that we don't have to

worry about whether the evidence is true

or isn't true we're going to accept the

evidence in these arguments and we're

gonna question whether or not they

establish the conclusion our path to

success in the assumption family hinges

on our ability to evaluate these

arguments and find the gap in the

reasoning and we want to accept the

evidence but question whether the

conclusion follows from it in fact in

every single question in the assumption

family the answer to whether the

argument is valid or not is that it is

not valid and if we can figure out what

the gap is an argument that will take us

to the right answer

another important family in logical

reasoning is the function family 19% of

all questions and logical reasoning

belong to the function family and these

are questions that are measuring our

ability to abstract from the reasoning

to understand the purpose and role and

how things work within an argument so

we're really kind of slicing and dicing

and understanding the mechanisms that

drive arguments and the roles that

claims are playing within them and

finally there's the inference family and

24% of all logical reasoning questions

belong to this family this is about

figuring out what we know based off of

what we just read so these tend to give

us statements instead of arguments and

ask us to figure out what we know based

off of what we just read now if we look

at the difficulty level of a logical

reasoning section in this section we

have the difficulty level of 25

questions and this is from prep tests 72

section 3 so this is a real logical

reasoning section and these questions

are weighted on a one to five point

scale you can see the difficulty level

it jumps around quite a bit and there

are different plateaus of difficulty but

each section as you move from one

logical reasoning section to another has

its own distinct curve and so if we look

at another section prep test 76 section

2 we'll see a completely different curve

one that looks actually a little bit

more challenging and more consistently

progressing in the more challenging

direction if we take all of the logical

reasoning sections from prep tests 62 to

81 and we take the average difficulty

level of each question at that point in

the section we start to see a unique

shape emerge and what we're looking at

here is the average difficulty trend

within a logical reasoning section

there's a challenge reward curve that

the LSAT likes to use which essentially

reward students for having accomplished

something that was hard and we get two

of them so as we move past question 12

and into the early teens we have a

little bit of a reward and as we get

past question 21 22 we start to get a

little bit more reward as well

essentially what this is doing is there

are some students who will not make it

all the way through the section and this

is giving them their reward and there

are some students who will make it to

the end of the section and questions 23

to 25 are giving them their reward so a

good way to think about the difficulty

level as you're moving through the

section is to break it up into thirds we

can look at the first third as being the

easiest third the middle third is being

a little bit more challenging and the

final third as being the hardest and the

kind of mindset that's appropriate for

each of these parts of the logical

reasoning section is different and by

using a different mindset it will more

easily allow you to arrive at the kind

of thinking that's going to get you to

the right answer

and so let me explain to you what what I

mean by that in the first third of the

section the way you think about these

questions should be driven primarily by

intuition

you shouldn't overanalyze you can use

what you know about the real world and

that information will be helpful in

terms of helping you come up with ideas

of how to counter an argument or a

button we really want to rely on our

everyday experience in order to be able

to move quickly through these questions

to provide an example of the kind of

thinking that is intuitive well let's

look at this argument here that blue

cars are the fastest cars on the road

therefore you should buy a blue car well

that argument rests on an assumption

it's not guaranteed that you should buy

a blue car even though blue cars are the

fastest cars on the road and there are

many assumptions that are possible for

you to come up with so the kind of

thinking that is going to help you

figure out how to attack this argument

or how to help this argument is going to

be based off of your understanding of

the real world so if you think about

what's an assumption of this argument

what you might come up with is different

than when someone else might come up

with because there are many things that

are possible so take a second think

about what's an assumption here and then

compare that idea or those ideas that

you've come up with the following one

assumption would be that you should buy

the fastest car on the road that was

actually never stated in the evidence

and so that recommendation that is

involved in the conclusion needs to be

assumed that you should actually go out

and do something about blue cars being

the fastest cars on the road or you

could think about it more from a feature

perspective is speed really the most

important feature for you maybe or maybe

not the assumption of this argument is

as speed is more important than

something like safety but then once you

get down this feature mechanism you

could actually go for a very long ways

speed is more important than fuel

efficiency or speed is more important

than affordability there are lots of

features that you might prioritize over

speed and if any one of them were true

that would be a problem for this

argument so when we're thinking about

how to attack the argument we really

want to be using real-world thinking

ideas that shouldn't be very

academic or esoteric in nature they

should be how you would understand the

argument in from a real-world

perspective once you've figured out

what's wrong with argument then we you

want to use that to anticipate what an

answer could sound like and then go find

that directly in the answer choices and

typically you'll find that there's one

answer choice that speaks to that idea

but as you move deeper into the section

one way in which they start to increase

the difficulty level is by creating more

and more answer choices that look very

tempting that look like they might

actually do the trick and so you'll find

yourself tempted between two choices

more and more often as you get deeper

into the section to deal with these

tempting but wrong answer choices it's

very important to understand how they

build trap answers ones that will be

very tempting even though they're wrong

suppose you're looking at a question and

you've gone through and you've

eliminated B and D and E but now you're

stuck between choices a and C and you're

not quite sure which one of them is the

right answer in fact on your first read

they both look like they're saying the

same thing well to get good at logical

reasoning it's really important to be

able to identify specific kinds of traps

and those traps are going to fall into

three different buckets which we'll talk

about in a second here in this example

question if we look at the difference

between answer choices a and C we'll see

that they both use the word if within

the sentence but they use it at

different places within it and that

different placement of the word if sends

the directional relationship implied by

these answer traces in opposite

directions

so if we look at a choice a the word if

introduces the term decrease in profits

and that tells us that decrease in

profits is the sufficient condition of a

conditional relationship and that the

necessary condition is that the price

paid for beans actually went up so this

is building an if-then relationship

between two terms it's the same two

terms that are presented in answer

choice C but if we look at entra C in

where the word if is if is now

introducing the idea that the price paid

for the coffee beans is gonna go up and

so what this is doing is its reversing

the direction of the relationship so

shoving if in two different places

within the answer choice they've created

essentially two different ideas even

though they look very very similar at

the beginning now it turns out that in

this case we wanted the relationship

between the price paid for beans going

up and a decrease in profits and that

means that answer is a was reversing the

relationship that we were looking for

and reversal is probably the number one

trap answer that you need to be able to

look out for when you're working in the

logical reasoning section there are lots

of different types of trap answer

patterns they all fall into three

general buckets though those relating to

scope those relating to logic and those

relating to degree here are a couple

examples of each but there are many more

for you to learn essentially for each

question type there are three to five

trap answer patterns you really need to

know and be aware of so that you're

looking for specific things in the

answer choices and are able to get rid

of those tempting but wrong ones what

makes the questions in the final third

of the section so challenging is that

not only do we have trap answers to pay

attention to but we also have arguments

that are much harder to get our heads

around instead of talking about things

like cars they'll start talking about

things like an through coast or fossils

things that you and I typically can't

relate to and so therefore have a hard

time using our intuition to understand

what's wrong with the argument and so

for these arguments we're gonna use

reasoning structures in order to be able

to identify the gap in the reasoning

there are three types of reasoning

structures that you really need to be on

the lookout for when you're reading

through these arguments as well as the

answer choices in order to be

if I trap answer patterns but the

reasoning structure is that you really

need to know about our conditional logic

causation in comparison for conditional

logic works is it builds together a

series of conditional relationships like

if a then B and if B then C and it draws

a conclusion from them that links them

together using the transitive property

so these two would suggest that if a is

true then C is true by understanding the

argument in this manner when there's a

gap in the reasoning we'll be able to

identify more clearly what is that gap

and and what should that relationship

look like between the unconnected terms

conditional logic is a really important

reasoning structure in logical reasoning

in fact 54% of all logical reasoning

questions use or rely on conditional

logic that doesn't mean that you should

go out in diagram 54% of logical

reasoning questions but it does mean

that at the heart of the question or

maybe on the periphery of the question

there is somewhere contained a

conditional relationship that playing a

role in how you're supposed to work

through the question and understanding

that if then idea will be super helpful

especially when you get to the harder

questions next we have causal reasoning

structures and a causal reasoning

structure is very similar to a

conditional reasoning structure in that

it's building a relationship between a

and B but the connection is deeper than

in a conditional relationship causation

implies conditionality but

conditionality does not imply causation

and so the connection that's implied

with a causal relationship is deeper

stronger than one with conditionality a

causal relationship implies that one

thing is responsible for the other

whereas conditionality simply gives you

a correlation between those two events a

perfect correlation in one direction but

there's a correlation nonetheless so in

causation a causes B & B causes C

therefore a causes C we can work through

causal chains the same way we can work

through conditional chains now causation

plays a role in 34% of all logical

reasoning questions it's a really

important reasoning structure maybe not

as important as conditional logic but on

some question types it's the main player

and it's really important

when you really want to be thinking

within a conditional mindset and that's

typically based off of the question type

finally there are also comparative

reasoning structures so you might have a

statement that says a is less than B and

another one that says that B is less

than C from them we can infer that a is

less than C so we can work through

comparative chains the same way we can

work the causal or conditional chains

comparison plays a role in 65% of all

logical reasoning questions making it

the most important reasoning structure

for you to be paying attention to

typically you'll see that a comparison

works either by comparing two different

things at a point in time let's say the

effectiveness of medication X versus the

effectiveness of medication Y or one

thing at two different points in time

let's say the population of City a today

versus a population of City a ten years

ago so coming back to the overall

difficulty level of the section you can

see that in the first third you really

want to be taking an intuitive approach

not over analyzing don't bring in too

much process and go with your intuition

as you move into the middle third of the

section you still primarily want to use

your intuitive reasoning to understand

the arguments and define the gap in the

reasoning that may be more true for some

than for others but you're gonna find

that as you look at the choices that

trap answers in order to be able to make

those eliminations you really need to

understand how they build tempting but

wrong answer choices and use those trap

answer patterns to make the eliminations

and then in that last third use

reasoning structures to better

understand the argument and to identify

the gap in its reasoning so you can

anticipate what an answer would sound

like

but even after you've gone to all that

work you're still going to need trap

answers to make eliminations in the

choices so there are three keys to

mastering logical reasoning first you

need to understand argument structure

how do you identify conclusions how do

you identify evidence how do you find

out opposing points you need to be able

to use keywords to help you organize

arguments then you need to use keywords

to help you identify reasoning

structures and better anticipate what

the missing gap would look like and use

trap answer patterns to work from wrong

to right through the harder questions

so that's it for today's lesson on how

to master logical reasoning I invite you

to check out these other videos or visit

us today at LSAT lab calm

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