The word UNLESS can be a blessing or a curse on the LSAT. This quick lesson will help make it a blessing for you.

Check out the bottom of this article for more LSAT articles, lessons and tips.

Unless is often found in the more difficult Logical Reasoning questions as well as in the Logic Games section of the LSAT.

Here are some of the LSAT questions where you’ll find UNLESS::

• Logical Reasoning
  • Necessary Assumptions
  • Sufficient Assumptions
  • Questions with Formal Logic or Conditional Reasoning Arguments
  • Many of the more difficult Logical Reasoning Questions
• Logic Games (Analytical Reasoning)
  • Many Grouping Games
  • Games with formal logic or conditional reasoning
  • Some of the more difficult logic games

UNLESS is often used on the LSAT to create complex logical structures that frequently confuse or slow down LSAT students.

If you know how to properly approach UNLESS statements you can make some of the more difficult LSAT questions much easier!

Here’s how to make UNLESS statements easy

Let’s start with a simple UNLESS statement:

You cannot fly unless you have wings

This statement is relatively simple so you don’t really need to change it in order to understand the meaning. But on the LSAT they can get much more complex than this, and if this statement were in a logic game you would still want to simplify to help with your game diagram and rules.

The process of simplifying an UNLESS statement is the same for any complex formal logic or conditional reasoning statement – you want to turn it into a basic IF – THEN statement. This makes it much easier to read and understand logically and will help you answer the question faster and more accurately. It also helps you diagram the statement quickly and easily for logic games.

IF – THEN statements are simply a statement with two parts – the first part follows the word IF and is the sufficient condition, the second part follows the word THEN and is the necessary condition. Don’t worry too much about the idea of “sufficient and necessary conditions right now” they’re not necessary in order to understand and utilize this concept.

In order to convert ANY UNLESS statement into a basic IF THEN statement you just need to follow the following steps:

1. Separate the statement into two parts (in this case Part 1: Cannot Fly, Part 2: have wings)
2. Pick one part. Either one, it doesn’t matter. (let’s pick Part 1: Cannot Fly)
3. Negate this part – this means to change if from positive to negative or in this case from negative (Cannot Fly) to positive (Can Fly)
4. Put that part first in your IF THEN statement – after the IF (so we get IF Can Fly)
5. Then take the other part and put it after the THEN – but don’t change or negate it at all (so we have THEN have wings)
6. You now have a complete IF THEN statement from your UNLESS statement (In this case: IF you can fly THEN you have wings)

The key elements here are to just pick any of the two parts, put it first (after the IF) and make sure you negate it. Also make sure you do not change the second part – the part that you put after THEN (don’t negate it)

Once you have this IF THEN statement you can also do the contra-positive of the statement for another IF THEN statement. For more on how to do this check out our complete LSAT courses.

Here’s another example from an actual LSAT question:

No form of psychotherapy that focuses on changing the patient’s unconscious beliefs and desires can be effective unless it also helps change beliefs that are under the patient’s direct conscious control.

Here’s our step by step approach

1. Two parts: Part 1: psychotherapy that focuses on changing the patient’s unconscious beliefs and desires CANNOT be effective Part 2: helps change beliefs that are under the patient’s direct conscious control
2. Pick one part. This time let’s try picking Part 2: helps change beliefs that are under the patient’s direct conscious control
3. Negate this part: It does NOT help change beliefs that are under the patient’s direct conscious control
4. Put that part first in your IF THEN statement – after the IF: IF it does NOT help change beliefs that are under patient control THEN …
5. Then take the other part and put it after the THEN – but don’t change or negate it at all: THEN psychotherapy that focuses on changing the patient’s unconscious beliefs and desires CANNOT be effective
6. You now have a complete IF THEN statement: IF it does NOT help change beliefs that are under patient control THEN psychotherapy that focuses on changing the patient’s unconscious beliefs and desires CANNOT be effective

Note that when we picked out Part 1: we changed it from “No form of psychotherapy… can be effective” to “psychotherapy….cannot be effective” – these two statements have the same meaning, but putting NO as CANNOT makes it a bit easier to understand. It can be very effective to simplify statements like this as you write them. For more on how to do this check out our complete LSAT courses.

So how will this help you on the exam? An IF THEN statement is much more useful as you know exactly what happens in a given situation. For example, now if you are told that a certain form of psychotherapy does NOT help change beliefs under patient control then you can answer easily that this psychotherapy that focuses on changing unconscious beliefs cannot be effective. For more on how to use this on actual LSAT questions and including lots of practice questions and explanations check out our complete LSAT courses.

Also, in the case of Logic Games you can use this to create a very simple rule for your diagrams.

You can also check out this complete question and explanation using unless statements. It’s a difficult question but it demonstrates how effective changing UNLESS to IF THEN can be on the LSAT.

Here’s some more LSAT articles to help you with formal logic and conditional reasoning:

• Necessary and Sufficient Conditions
• More Unless statements
• If and Only If
• Complete LSAT Courses

Check out the latest LSAT Course Video

Enroll for the full course here

Here we take a look at how since is used on the LSAT and how you can use it to better understand arguments in LSAT questions.

We often see “since” used in one of the following constructions. They are basically the same but reversed:

1. “Conclusion”, since “premise.”
2. Since, “premise”, “conclusion.”

So “since” is often part of a two part sentence. One part being your conclusion or sub-conclusion and the other part being a premise supporting that conclusion.

Let’s look at an actual LSAT question from the June 2007 LSAT exam:

Novel X and Novel Y are both semiautobiographical
novels and contain many very similar themes and
situations, which might lead one to suspect plagiarism
on the part of one of the authors. However, it is more
likely that the similarity of themes and situations in the
two novels is merely coincidental, since both authors are
from very similar backgrounds and have led similar
lives.
Which one of the following most accurately expresses
the conclusion drawn in the argument?

(full question and answers below)

You can see where since is used in the last sentence.

“However, it is more likely that the similarity of themes and situations in the two novels is merely coincidental, since both authors are from very similar backgrounds and have led similar lives.”

Here we have our conclusion as the first part of the sentence, followed by SINCE and then a premise which supports the conclusion directly.

Understanding this construction can help you break down the components of an argument faster.

BEWARE though, merely because we have found “a conclusion” does not necessarily mean it is “the main conclusion” of the argument.  In this case it is but in other questions this conclusion may go on to support a further conclusion. The key is to check whether this conclusion goes on to support some further part of the argument (making this a sub-conclusion) or if the rest of the argument supports this conclusion (making it the  main one).

More help with breaking down arguments in our LSAT Prep Course online.

The full questions and answers for the question above are here:

Novel X and Novel Y are both semiautobiographical
novels and contain many very similar themes and
situations, which might lead one to suspect plagiarism
on the part of one of the authors. However, it is more
likely that the similarity of themes and situations in the
two novels is merely coincidental, since both authors are
from very similar backgrounds and have led similar
lives.

Which one of the following most accurately expresses
the conclusion drawn in the argument?

(A) Novel X and Novel Y are both
semiautobiographical novels, and the two
novels contain many very similar themes and
situations.

(B) The fact that Novel X and Novel Y are both
semiautobiographical novels and contain many
very similar themes and situations might lead
one to suspect plagiarism on the part of one of
the authors.

(C) The author of Novel X and the author of
Novel Y are from very similar backgrounds
and have led very similar lives.

(D) It is less likely that one of the authors of
Novel X or Novel Y is guilty of plagiarism
than that the similarity of themes and
situations in the two novels is merely
coincidental.

(E) If the authors of Novel X and Novel Y are from
very similar backgrounds and have led similar
lives, suspicions that either of the authors
plagiarized are very likely to be unwarranted.

Correct answer: (D) This simply restates the conclusion expressed before “since” in our last sentence.

Sample Amount Words for the LSAT

• none
• few / a few
• some
• many
• lots
• most
• all
• not all

There are more but these are the basics. For all amount words you should have a clear idea as to what they represent in numerical terms or percentages. For example a few means more than one, most means more than half or greater than 50% and all, well it means every single one or 100%.

It seems a simple concept but many students get tripped up by these words or worse yet, don’t pay them the attention they are due when reading logical reasoning questions on the LSAT.

The correct answer often turns on these words and they can be far more important than the specifics of the stimulus or question scenario. Focusing on these words can often allow you to quickly eliminate or select answer choices.

Here’s an example of a simple LSAT question, taken from the June 2007 Official LSAT prep test. It’s not particularly difficult but give it a try and then we’ll take a look at the amount words in it.

Economist: Every business strives to increase its

productivity, for this increases profits for the

owners and the likelihood that the business will

survive. But not all efforts to increase

productivity are beneficial to the business as a

whole. Often, attempts to increase productivity

decrease the number of employees, which clearly

harms the dismissed employees as well as the

sense of security of the retained employees.

Which one of the following most accurately expresses

the main conclusion of the economist’s argument?

(A) If an action taken to secure the survival of a

business fails to enhance the welfare of the

business’s employees, that action cannot be

good for the business as a whole.

(B) Some measures taken by a business to increase

productivity fail to be beneficial to the business

as a whole.

(C) Only if the employees of a business are also its

owners will the interests of the employees and

owners coincide, enabling measures that will

be beneficial to the business as a whole.

(D) There is no business that does not make efforts

to increase its productivity.

(E) Decreasing the number of employees in a

business undermines the sense of security of

retained employees.

So we are asked to find the main conclusion. If you need more help with this, a complete analysis of how to do this for questions like this and much more complex ones is included in our LSAT prep course. For now let’s simply say that your main idea will be the part of the argument that is supported, directly or indirectly, by each other part of the argument. Here we have four parts:

1. every business tries to increase productivity
2. productivity increases profits and chances of survival
3. not all efforts to increase productivity are good for the whole business
4. often attempts to increase productivity decreases employees which harms employees

So where does the support flow to?  Our second sentence receives support from the other areas of the argument.

But not all efforts to increase productivity are beneficial to the business as a whole.

From the points above. 1. sets up the situation – many arguments provide some background information to set up the situation. This is not the conclusion because the other parts of the argument do not all support  this idea that ALL businesses try to increase profitability.

2. This explains why all businesses try for increased productivity, while it does support 1. that does not make 1. our conclusion as 1. still goes on to support the other parts of the argument

3. this is our conclusion. it does not support other parts of the argument and is supported by the other parts.

4. this demonstrates why 3. is the case by giving us specific examples it clearly supports 3. which is our conclusion.

Looking at our stimulus and answer choices now to find our amount words we see  a number of them and each can help us in understanding the question and finding the correct answer.

The amount words are highlighted in red here.

I have also highlighted some other words that are important to look for. Blue represents some changes in amounts. Green represents a level of certainty e.g. are we certain or somewhat less than certain about an idea.

For now we’ll focus on the amount words in red.

Our conclusion tells us that NOT ALL efforts are positive to the whole business. If not all are positive than some must be negative. And we see that expressed in our correct answer choice (B) “Some measures taken by a business to increase productivity fail to be beneficial to the business as a whole.” This expresses the same idea as our conclusion. They have just switched the amount words from “not all” to some.

The other words we have highlighted can also help you in understanding and interpreting the argument and answer choices. In other questions these words can mean the difference between an incorrect and correct answer. Focus on not only the words of amount but also certainty and it will help you increase your logical reasoning scores.

All actual LSAT questions printed within this work are used with the permission of Law School Admission Council, Inc., Box 2000, Newtown, PA 18940, the copyright owner.  LSAC does not review or endorse specific test preparation materials or services, and inclusion of licensed LSAT questions within this work does not imply the review or endorsement of LSAC.  LSAT is a registered trademark of LSAC.

You can find IF THEN statements with necessary and sufficient conditions in both the Logic Games and Logical Reasoning sections of the LSAT.
Here’s another look at our IF THEN statements…
IF A then B
A is our sufficient condition – if we have A then we will always have B or in other words A is sufficient to know that we must have B
B is our necessary condition – B is necessary or required in order to have A. So if we do not have B then we will not have A. We see this in our contra-positive IF not B then not A.

Here is a basic logical reasoning style examples of these conditions:
The local theatre will only produce a new play if it has seen previous success in another theatre. My play has never been successful in another theatre, therefore my play will not be produced by the local theatre.
The necessary condition here is that a play “has seen previous success in another theatre”
In the absence of this condition we do not achieve our other condition – the sufficient one.
The sufficient condition is “the local theatre producing a play”

If I tell you that Bob’s play was produced by the local theatre, then you know for sure that Bob’s play has seen previous success in other theatres as that is a requirement for this local theatre to produce it. So being produced locally is sufficient to know that the play saw success in another theatre.
Another way to look at necessary and sufficient conditions is this:

I require air to live. (air is a necessary condition for my life)
If I am alive tomorrow then you know I have air. (being alive is sufficient for you to know that I have air)

Here’s another example of a logical reasoning style question that uses necessary and sufficient conditions/formal logic to get to the correct answer.
Whenever you encounter a logical reasoning question that uses the following words, it can be a good idea to diagram some of the statements in the argument out. You only need to do this if you are having trouble understanding the logic of the argument, often it is easy to understand and faster without a diagram. But if you’re struggling, a quick diagram can help a lot.
The words that make for easier diagrams are:
IF THEN
ONLY IF
UNLESS
IF BUT ONLY IF
IF AND ONLY IF
The example with Miley Cyrus and LSAT conditional statements above is a great example of when diagramming helps.

Also here’s some more articles on formal logic & conditional reasoning.

For complete coverage of this topic and tonnes of practice questions explained. Check out our LSAT Prep Course.

Before we get into the issue, here’s a quick look at what the stimulus and stem are: (or you can skip ahead)
What’s a stimulus?
The stimulus is a short argument or set of facts and is the first thing presented to you in every logical reasoning LSAT question.

What’s a question stem?
The question stem is the actual question e.g. What is the main point of the argument above?
The question stem is presented second, after the stimulus, in every logical reasoning LSAT question.

There has been some debate over whether to read the question stem first or stimulus first when reading a logical reasoning LSAT question.

Here are the pros for reading the question stem first:

1. It makes it clear what you are looking for when you read the stimulus. e.g. if the stem asks for the main point you can focus only on the main point and not worry about looking for flaws or assumptions in the argument.
2. It gives you something to think about and analyze for while you read so that you are not reading and daydreaming or thinking of something else.
3. It helps you focus on the issue while you read (a combination of 1 & 2 above).
4. If you have a pre-determined strategy for each question type you can now use that strategy as you read the question.

Cons:

1. It can confuse you by making you think about the question stem and the stimulus at the same time.
2. It can take more time as you may read the question stem twice. Once before the stimulus and once after.

Here are the pros for the conventional strategy, reading the stimulus first and then the question stem:

1. It’s the natural order and so you are likely to fall back to this order often.
2. If allows you to absorb and understand the entire argument before biasing your view with a question stem.
3. You read the argument with a clear mind not clouded by a particular question. Thinking about only the stimulus may help you understand it better.

Cons:

1. You need to analyze the stimulus for many things: flaws, assumptions, conclusion, premises, format and structure and more – as you have no idea what you will be asked about
2. You may need to read the stimulus again after you have read the question in order to go back and find what the question stem was looking for.

When we look at the pros and cons it seem fairly equal, if not slightly in favor of reading the question stem first.

The reality is that the right approach depends on you the student. We have received feedback from hundreds of students on this issue and some perform better with stems first and other with stimuli first. Although most actually score higher using the stimulus first method.

So what should you do?

Take two Logical Reasoning LSAT sections reading the stems first, and two reading the stimuli first. If you do much better using one or the other method go with that method from now on.
If the stem method seems too awkward or you don’t like it, stay away from it and go with the stimulus first.
If the the results are very similar then go with the stimulus first method.
If you’re not sure or don’t want to try the stem first method then go with the stimulus first method.

Once you pick a method, every few weeks or so try a section or two using the other method. It can help you to look at the questions in a different light and often allows insights that can help increase your score.

For a much more detailed look at LSAT strategies, try our online LSAT prep course.

Since Miley Cyrus would never date a boy who did not believe in marriage, and anyone who truly understands romance believes in marriage, only a boy who truly understands romance would have any chance of dating Miley Cyrus.

The reasoning in the argument is flawed because the argument ignores the possibility that some people who

(A) have no chance of dating Miley Cyrus do not truly understand romance
(B) truly understand romance have no chance of dating Miley Cyrus
(C) truly understand romance do not believe in marriage
(D) believe in marriage have no chance of dating Miley Cyrus
(E) believe in marriage do not truly understand romance

Read on for the explanation and answer…
This is a great example of a flaw LSAT question with formal logic or conditional reasoning. You’re looking to identify what’s wrong with the argument but first you’ll need to breakdown the conditional reasoning. Let’s start by drawing out our basic if-then statements:

We start with a couple of premises:

“Since Miley Cyrus would never date a boy who did not believe in marriage…”
and
“anyone who truly understands romance believes in marriage”

With any LSAT question involving conditional reasoning you want to turn the statements into basic IF-THEN statements. Our premises then become:

IF a boy does not believe in marriage THEN he cannot date Miley Cyrus
and
IF you understand romance THEN you believe in marriage

You can represent these graphically as follows:

Usually you would use just the letters B and D or BM and DM to represent belief in marriage and dating Miley Cyrus but we’ve used the full words here for ease of explanation. When you do this yourself on the actual or practice LSAT exams you should use only a single letter, it will speed things up.

These two IF-THEN statements are our premises and are known to be true for sure. We then have our conclusion which is suspect as it makes a conclusion that cannot be drawn on the basis of the two premises provided.

Our conclusion is a bit tricky as it’s an “ONLY IF” statement. The easy trick for these statements is to remember that you reverse the order of the statement when you turn it into a basic IF-THEN statement. e.g. ONLY IF A THEN B becomes
IF B THEN A or IF B –> A

Our conclusion was “only a boy who truly understands romance would have any chance of dating Miley Cyrus” or in IF-THEN terms:

ONLY IF understand romance THEN date Miley Cyrus
and reversing that to a basic IF-THEN statement we get:

IF Dating Miley Cyrus THEN understand romance

We can represent this graphically as:

So now we have our premises and conclusion expressed as IF-THEN statements. You can answer the question from here or you can go on to add some additional information by taking the contra-positives of each IF-THEN statement. For a detailed explanation of how to set up the contra-positive and IF-THEN statements check out this article, or try our LSAT Prep Course Online.

So here’s our complete story including contra-positives:

Premise 1:


Premise 2:

Conclusion:

So what’s wrong with our conclusion?  Our conclusion starts with the information on the left side of the IF THEN statement. Which is either “If you are dating Miley Cyrus” or from the contra-positive “If you don’t understand romance”

Let’s start with the first one: “If you are dating Miley Cyrus” – what do we know about someone who is dating Miley Cyrus? The way to find out is to skim read down the left side of all your equations in the premises. The premises are our facts so what we have there is known to be true. We skim the left side for something about a person “dating Miley” and we can then follow it to the right to find out more information. So we find the statement:

So we can conclude that if you’re dating Miley Cyrus, you believe in marriage. But our conclusion takes this further and concludes that you also understand romance. Can we go this far?  You can find out by continuing to follow the chain of logic in your premises, we’ve gone from dating Miley, to believing in marriage – what next? Nothing comes next! We have no statement that starts with belief in marriage on the left side and so we can draw no conclusions on this basis. So our conclusion went to far. It should have stopped with “Anyone who dates Miley Cyrus must believe in marriage.”  and not gone on to conclude they also understand marriage. So the error here is that the argument assumes that if you believe in marriage you also understand romance, or in other words and in the words of our question stem, it ignores the possibility that some people who believe in marriage do not truly understand romance.

With the information in our premises it’s possible that we have someone who dates Miley, believes in marriage but does not truly understand romance. This possibility was overlooked or ignored and so (E) is our correct answer.

A straw man argument is a fallacy based on misrepresentation of an opponent’s position. To “attack a straw man” is to create the illusion of having refuted a proposition by substituting a superficially similar proposition (the “straw man”), and refuting it, without ever having actually refuted the original position.

Or more simply: a straw man argument presents a weaker version of the opponents argument and attacks that weakened argument rather than the original argument. It often involves rephrasing the opposing argument in order to make it more vulnerable to attack.

E.g.
Person A: We should liberalize the laws on marijuana.
Person B: No, any society with unrestricted access to intoxicants loses its work ethic and goes only for immediate gratification.

The proposal was to relax laws on marijuana. Person B has exaggerated this to a position harder to defend, i.e., “unrestricted access to intoxicants”.

Straw Man arguments can be described on the LSAT as:

“portrays opponents views as more extreme than they actually are”
“rephrases the opposing viewpoint in order to make it more vulnerable to criticism”
“distorts the proposal made by the advocates”
“misstates the original position held by the politician in order to make it easier to refute”

These statements can be included either as a correct or incorrect answer. By understanding the straw man fallacy you will be faster at identifying these answer choices as correct or incorrect.

For free access to a complete “Flawed Reasoning Tutorial” email: freetutorial@alpha-score.com
The tutorial is online and interactive and includes 16 other common forms of flawed reasoning found on the LSAT.

If the novel were successful, it would be produced as a movie or adapted as a theatre script. However, this novel is not successful, therefore, we must conclude that it will neither become a movie nor will it be adapted as a theatre script.

The argument’s reasoning is flawed because the argument:

(A) fails to draw the conclusion that the novel will not both be produced as a movie and be adapted as a theatre script, rather than that it will do neither
(B) fails to explain in exactly what way the novel is unsuccessful
(C) equates the novel’s aesthetic worth with its commercial success
(D) presumes, without providing justification, that there are no further avenues for the novel other than production as a movie or adaptation as a theatre script
(E) fails to recognize that the novel’s not satisfying one sufficient condition does not preclude its satisfying a different sufficient condition for production as a movie or adaptation as a theatre script

This is a formal logic question. It uses conditional reasoning or if then statements.
For a full analysis of IF THEN statements and formal logic for logical reasoning questions see our free LSAT course: Formal Logic Tutorial
And here Practice Questions

Let’s analyze our stimulus.
Our first premise is: IF the novel is successful THEN movie or script
Our second premise: This novel is NOT successful.
Conclusion: NOT movie nor script

This is flawed formal logic. The mistake here is that we have reversed our IF THEN statement. As you can see from the tutorials in formal logic Formal Logic Tutorial you cannot reverse your IF THEN statement except as a contra positive. The contra positive of our IF THEN statement is as follows:

Original Statement: IF the novel is successful THEN movie or script
Contra-Positive: IF there is NOT a movie or script THEN the novel was NOT successful

There is nothing else you can conclude from this original statement or premise. This means that our conclusion is a flawed conclusion. The conclusion tries to state the following:

Conclusion: IF NOT successful THEN NOT movie or script.

We cannot draw this conclusion from our original premise. By drawing this conclusion we fail to recognize that the novel could become a movie or script by some other means than success. For example, maybe all novels about children are made into movies giving us the statement IF novel is about children THEN movie. This would give us another avenue to arrive at a movie or script despite the novel not being successful.

So our correct answer choice is (E). The argument fails to recognize that the novel’s not satisfying one sufficient condition (being successful) does not preclude its satisfying a different sufficient condition (some other means such as being about children) for production as a movie or adaptation as a theatre script.

Which one of the following is an assumption required by the argument?

(A) Law professors who disseminate the evaluation forms selectively, do so only to the students they personally like.
(B) Students can wisely and insightfully asses a professor’s performance before the end of the school year.
(C) The old system of evaluation should not be used in any law school.
(D) Nearly all law professors who do not disseminate the evaluation forms do so because they believe the students will give negative evaluations.
(E) Law students who are unhappy with their professors are not more likely than students who are happy with their professors to submit an online evaluation.

Explanation:

This is an assumption question. We are looking to determine which statement is required by the argument. The author of the argument has made an assumption or skipped over a point in the logic in order to come the the conclusion and this assumption will be our correct answer.
First we should determine the conclusion of the argument. Our conclusion here is the last sentence of the argument: “Therefore, evaluations under the online system will accurately reflect the distribution of student opinion about teaching performance”. Notice that the word “Therefore” signals the start of the conclusion in this case.
Prior to this conclusion the argument proceeds in summary as follows:
- there is an old system of evaluation using paper forms
- these forms are submitted on the last day of classes
- these forms are not submitted to all students due to various biases and problems
- a new system allows all students to submit evaluations online
- the new system allows for evaluations at any point in the year

(A) The fact that professors disseminate the forms only to students they like is not required for our conclusion. It may help discredit the existing system but does not make the new system accurate as our conclusion requires.
(B) Many students choose this answer choice at it would seem to be an assumption that helps our conclusion. However, our conclusion requires only that the new system accurately reflects student opinion, not whether that opinion is wise or insightful. If our students opinion is not wise or insightful as this answer offers, our new system could still accurately reflect the students unwise opinions.
(C) This answer choice is much too strong. Our conclusion does not require nor does it go so far as to say that the old system should not be used at ANY law school. Look out for strong wording such as ALL, ANY, NONE, EVERY etc.
(D) Once again this answer choice has strong working, with ALL professors. However, the real issue with this answer choice is that our conclusion does not depend upon the belief of our professors in choosing not to hand out the forms. Our conclusion relates only to the accuracy of our new system.
(E) This is our correct answer. This assumption is required for our conclusion. If this assumption is not true then our unhappy students would be more likely to submit online evaluations and the online system would be negatively biased making it an inaccurate expression of student opinion and negating our conclusion. Our argument requires this assumption to be effective and so we have our correct answer choice. This technique of reversing our answer choice in assumption questions and testing the effect on our conclusion is a great way to check for correct answers. A required assumption when reversed will destroy your conclusion.