Frequently Appearing Patterns on the GMAT CR Section with Practice Q

There are a few basic patterns which frequently appear on the GMAT CR Section and understanding these patterns makes it much easier to work many arguments. Not only would it make it easier to work the argument but also acts as a shortcut for uncovering the assumptions, and dealing with Strengthen and Weaken questions as well.

Collaborated with assistance from the Princeton Review Manual, here is a summary of my notes for the various CR Patterns.

The most common argument patterns are as follows:

1. Causal Patterns
2. Planning Patterns
3. Sampling Patterns
4. Interpretation of Evidence
5. Analogy Pattern

I will discuss the basic setup of these different argument patterns and how best to identify them. I hope you find this helpful when cracking down the CR section.

1. Causal Patterns

Premise: A and B are correlated. Or, B follows A.
Conclusion: A caused B

Assumptions:
[*] It's not a coincidence
[*] There's no other cause

Weaken:
[*] Offer evidence to show that it is a coincidence
[*] Show a counter-example in which the cause is presented but the effect does not follow.
[*] Identify other possible causes.

Strengthen
[*] Offer evidence to show that it is not likely to be a coincidence.
[*] Provide an additional example of the cause being present and the effect following.
[*] Rule out other possible causes.

Eg:
A study indicated that adults who listen to classical music regularly are less likely to have anxiety disorders. Clearly, classical music helps calm the nerves and lowers anxiety.

Here, the author concludes that classical music helps calm the nerves and lowers anxiety because the study found a correlation between listening to classical music and experiencing a lower likelihood of having anxiety disorders. A causes B. However, the fact that two things are related does not prove that one caused the other.

To author rules out two possibilities:

1. The results noted in the study were merely coincidental.
2. Listening to classical music was the only factor for lowered anxiety among the subjects.

We can weaken this argument by attacking the causal assumptions.

1. We can simply state that the link between classical music and anxiety was coincidental.
2. We can show a counterexample: people who routinely listen to classical music but still have anxiety disorders.
3. We can break the causal link by showing that another factor explains the lower rate of anxiety disorder in people who listen to classical music.

On the flipside, this argument can be strengthened by bolstering the causal assumptions.

1. We can show that the results were not coincidental by noting that other well-connected studies in several other scientific journals had found similar results.
2. We can rule out the possibility of factors other than classical music playing a role in reducing anxiety.

2. Planning Pattern

Premise: There is a plan to solve a problem.
Conclusion: Do the plan!

Assumption
[*] There are no problems with the plan.

Weaken
[*] Point out problems with the plan.

Strengthen
[*] Offer solutions to any potential problems with the plan.

Eg:
Gotham City has seen a rise in crime over the past 5 years. The chief of police has recently installed video surveillance cameras at all major intersections in the neighborhoods with the highest crime rate. We can now expect to see a drop in the crime rate.

The argument concludes that the crime rate will drop because there are recently installed video cameras at all major intersections in the neighborhoods with the highest crime rates. The assumption is that the surveillance cameras will actually reduce the incidence of crime.

To weaken the argument, we attack the assumption by pointing out potential problems with the plan:

1. Crime is not limited to major intersections.
2. A reduction in crime in one area may lead to an increase in crime in another neighborhood.
3. Cameras often produce poor image quality.
4. Would-be criminals may not notice the cameras and so would not be deterred by their presence.

To strengthen the argument, we bolster the assumptions by offering solutions to any potential problems with the plan:

1. Suggest that state of the art cameras be installed with both a very wide scope and very good resolution.
2. Suggest that the city is conducting mass publicity of the surveillance camera program and the sentences will be enhanced for anyone caught on camera while committing a crime.

3. Sampling Pattern

Premise: Something is true for a subset of a population.
Conclusion: That thing is also true for the whole population.

Assumption:
[*] The sample is representative

Weaken:
[*] Show that the sample is not representative of the whole by showing a difference between the sample and the population.

Strengthen:
[*] Show that the sample is representative of the whole by establishing a similarity between the sample and the population.

Eg:
Contrary to popular belief, high school students overwhelmingly approve of the high school administrative staff. We know this to be true because the student council expressed admiration for the high school principal and her staff in the council's editorial for the school paper.

The author concludes that students approve of the school administration based on the student council's opinion as expressed in the paper. The gap is between the student council and the general student body, and the author draws on a sample population to reach a conclusion about the whole population. To make the link, we must assume that the council is an accurate reflection of the feelings of the general student population.

To weaken this argument, we attack the assumption:

1. We could break the link by proving that the student council's view does not represent the views of the rest of the students.
2. Maybe the student council is made up of sycophants who want to get favorable college recommendations from members of the administration.

To strengthen the argument, we bolster the assumptions:

1. Provide evidence that the student council's view is representative of the entire student body.
2. The student council is comprised of a good cross-section of all the students in the school.

4. Interpretation of Evidence

Premise: A fact or piece of evidence (often a statistic).
Conclusion: An interpretation of that evidence.

Assumption:
[*] There is no other way to interpret the facts.
[*] Be on a lookout for a shift between numbers and percentages or a misunderstanding of a statistical finding.

Weaken:
[*] Offer an alternate interpretation of the evidence.

Strengthen:
[*] Demonstrate that the evidence was correctly interpreted.

Eg:
Ninety percent of the population Prelandia lived in rural areas in 1800. Today, only 20 percent of the population lives in rural areas. Clearly, more people lived in the countryside two centuries ago.

The author believes that since the percentage of people living in rural areas decreased, the actual number of people living in the rural areas must have decreased. Hence, whether the conclusion is true depends on how the past and present populations compare. To make the link, we need to prove that the total population in the past and present are comparable.

To weaken this argument, we need to prove that the total population has changed:

1. If the country's population was 100 people in 1800, 90 of them lived in rural areas. If the population is 1000 people today, then 20 percent would be 200 people.
2. More people actually live in rural areas now, even though the percentage of the population has decreased.

To strengthen the argument, we prove the population is comparable:

1. If the population was 100 people in 1800 and 100 people today, we could say that 90 people lived in rural areas in the past and only 20 people live in rural areas today.
2. Prove that the author's interpretation of the statistical evidence is valid.

5. Analogy Pattern

Premise: True for X.
Conclusion: Also true for Y.

Assumption:
[*] X is similar to Y.

Weaken:
[*] Show that Y is different from X in relevant ways.

Strengthen:
[*] Demonstrate that X and Y are comparable in relevant ways.

Eg:
Contrary to opponent's charges that a single-payer health-care system cannot work in a democratic nation such as the United States, an overhaul of the American health-care system is necessary. Opponents of the single-payer system in the United States should remember that Canada, a nation with a strong democratic tradition, has run a viable single-payer health-care program for many years.

The author concludes that because a single-payer health-care system works in Canada, it will work in the United States as well. The gap is between the United States and Canada, and we must assume that they are similar enough to make the comparison valid.

We can weaken the argument by:

1. Suggesting reasons that the comparison is not valid.
2. We could say that the differences in population and economies of the two nations mean that policies that work in one country won't work in the other.

We can strengthen the argument by:

1. We could add additional reasons why the two nations may be compared.
2. Information about the similarities in the governmental structure of the U.S and Canada would make the conclusion more believable.

This summarizes the different patterns the test makers employ. Although, it may not be possible to apply these patterns to every question you see, having a good understanding will definitely give you an edge when dealing with Critical Reasoning. Please let me know what you think. I will be glad to further discuss these patterns in detail if required.

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