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How to Succeed on the MCAT Critical Analysis and Reasoning Section

Free CARS Strategy Guide (an alternative to Jack Westin or examkrackers )

The MCAT’s Critical Analysis and Reasoning Section (CARS) is hard. That much is obvious. It’s hard enough that Jack Westin charges thousands of dollars to learn his method. From all reports, Jack Westin is excellent, and I’m not one to begrudge a man his money. But, I think there’s a cheaper, more effective way of doing it.

In this post, I’ll explain how I approach MCAT CARS. It’s the same way I approached the LSAT Reading Comprehension section, which I scored in the 99th percentile on. This post is based on a passage from the MCAT Sample Test, the passage on heart disease. If you haven’t taken that yet, you should before reading this guide.

Now, without any further ado, let’s begin.

Overall MCAT CARS strategy

-Skim, then form one sentence summary of each paragraph, as well as how they all fit together

-Don’t get too much details! If you need to, just read the first and last sentence of each paragraph

-If any sentence takes too much time, skip it! You might not need to understand it at all.

-Then go to questions to see what more you need to know

-Let’s start with looking at the passage, then writing summaries. On the real test, I would advise you to avoid writing summaries if you can, and just keep mental track of it.

 

In the second half of the twentieth century, as the threat of communicable diseases receded, public medicine turned its attention to preventing and treating health problems that were not caused by germs. The death rates for chronic heart disease, in particular, seemed to be soaring after World War II. Some observers cautioned that the apparent increase might be the result of diagnostic advances, which had improved doctors’ ability to detect heart ailments. However, this possibility failed to deter the press and advocacy groups like the American Heart Association from declaring the arrival of a frightening epidemic.

Summary: Increase in incidence in heart disease in second half of twentieth century, maybe a signs of an epidemic?

 

One theory blamed the problem on the American diet, and specifically on cholesterol—both the kind that you ingest when you eat animal products and the kind that your body produces when you eat saturated fats. After all, cholesterol is one component of the plaque that clogs arteries and causes heart attacks. But isolating the true causes of coronary disease proved elusive. In addition to diet, multiple factors were potential contributors, including genetics and personal habits such as smoking. Numerous studies on diet proved so inconclusive that, in 1969, the National Institutes of Health found no hard evidence that what people ate had a significant impact on heart disease.

Summary: If epidemic, could be because diet, but hard to tell

 

Nevertheless, in the 1970s, the Select Committee on Nutrition and Human Needs decided to fight the apparent epidemic by making nutritional recommendations. Settling on the unproven theory that cholesterol was behind heart disease, the committee issued its guidelines in 1977. The guidelines urged people to reduce the fat that they consumed, principally by eating less meat and consuming fewer dairy products. The committee also advised raising carbohydrate intake and cutting one’s intake of cholesterol by a quarter.

Summary: Even though hard to tell, Committee still told people to reduce fat consumed.

 

Some of the country’s leading researchers spoke out against the guidelines and against population-wide dietary recommendations in general. Edward Ahrens, an expert in the chemistry of fatty substances at Rockefeller University, characterized the guidelines as “simplistic and a promoter of false hopes.” Ahrens complained that the guidelines treated the population as “a homogeneous group of [laboratory] rats while ignoring the wide variation” in individual diet and blood chemistry.

Summary: some people, like Ahrens, got mad at the committee.

 

The latest nutritional thinking has actually focused on carbohydrates as a potential cause of heart disease. Several studies have concluded that easily digestible carbohydrates, in particular—such as potatoes, white rice, bread from processed flour, and refined sugar—make it difficult to burn fat and also increase inflammations that can cause heart attacks.

Summary: Maybe it’s carbohydrates instead.

 

Supporters of the guidelines have increasingly struggled to justify them, sometimes resorting to political arguments. Without clear dietary guidelines, they claim, the food industry and other special interests could lobby political leaders and influence policy in unhealthy ways. But this argument makes sense only if you assume that the government’s guidelines will be any healthier. Supporters also argue that the government’s success in persuading people to stop smoking, equally paternalistic, justifies its efforts to change American eating habits. But the major scientific dissenters from government dietary policy are not especially concerned with governmental paternalism, though that is a legitimate issue. They dissent because they find the government’s evidence inadequate and its recommendations potentially harmful.

Summary: Supporters are still all for Committee, other scientists are mad.

 

The best thing that the U.S. government can do to promote health is to encourage people to develop their own individually-tailored diet and exercise programs, in consultation with health-care professionals. Otherwise, public health medicine risks violating the central principle of medical ethics: First, do no harm.

Summary: Long story short, we should just tell people to do their own thing.

 

Overall Passage Summary: To explain heart disease increase, maybe cholesterol, but establishment should stop being so confident that’s it’s cholesterol.

 

How to answer the CARS questions

-Once we summarize the passage, we can go onto the questions

-They tell us what additional information or reasoning we need from the passage. There’s no point in trying to figure that out before we go to the questions

-There are 4 main types of questions: Summarize, Detail, Critical Reasoning, and Inference. We’ll go through them one-by-one.

Summarize questions

– Summarize questions are what you should pick up in your summarizing (obviously)

-If you see a word like “essential”, “main idea”, or the like, it’s a summarize question. Let’s look at one of them.

 

Edward Ahrens’s criticism, as it is presented in the passage, essentially points to:

I. complexity.

II. flexibility.

III. diversity.

 

To start with, let’s find Ahrens’s criticism (obviously enough). I think I remember it from summarizing before…

Edward Ahrens, an expert in the chemistry of fatty substances at Rockefeller University, characterized the guidelines as “simplistic and a promoter of false hopes.” Ahrens complained that the guidelines treated the population as “a homogeneous group of [laboratory] rats while ignoring the wide variation” in individual diet and blood chemistry.

Right, he’s one of the criticizers of the cholesterol guidelines. When I read carefully, it’s clear that he’s mad that they are ignoring “variation in people” (i.e. diversity). I’d pick III only, but they won’t let me. Complexity is not bad as well, because he criticizes the guidelines as “simplistic”. Fits in well with our previous ideas, but also supported by evidence in the passage.

Once I know where to read, I read that section (and only that section) carefully. Then I use the answers in conjunction with my reasoning to form a proper summary.

 

Detail questions

-This is when we need to be really good at using key words from the question, as well as our summarizing from before, to tell us what exactly we need to read

-We can tell detail questions because they ask us directly what the passage or the author says, without requiring further interpretation

-Let’s take a look at a detail question

 

The author suggests that concluding that diet is responsible for heart disease would be:

A.mistaking cause for effect.

B.mistaking correlation for causation.

C.failing to consider a common cause.

D.failing to consider additional causes.

Key terms: “diet responsible for heart disease”

We know that we discuss diet in the passage that we summarized as “Summary: If epidemic, could be because diet, but hard to tell”. That might be enough information, but let’s be safe, and go back to that part of the passage for more information.

 

One theory blamed the problem on the American diet, and specifically on cholesterol—both the kind that you ingest when you eat animal products and the kind that your body produces when you eat saturated fats. After all, cholesterol is one component of the plaque that clogs arteries and causes heart attacks. [But isolating the true causes of coronary disease proved elusive. In addition to diet, multiple factors were potential contributors, including genetics and personal habits such as smoking.] Numerous studies on diet proved so inconclusive that, in 1969, the National Institutes of Health found no hard evidence that what people ate had a significant impact on heart disease.

Now that I’m back at that part of the passage, I have the information I need. I carefully read the necessary piece, and only that piece (it’s the part in brackets). This also makes sense: diet definitely seems to be part of it (so A,B,C are too aggressive in ruling out diet completely), but it’s not the whole explanation.

Critical Reasoning questions

-This type of questions asks about the logic of the passage: how facts lead to reasoning leads to conclusions

-You can tell a Critical Reasoning question if there’s any mention of strengthening or weakening an argument or conclusion, or if there’s mention of assumptions.

 

Which of the following, if assumed to be true, would provide the best evidence to support the author’s conclusion about how government should promote health?

A.Making the presentation of nutritional information on food packaging mandatory was a step in the right direction.

B.America’s obesity rate was far lower back when nutrition was largely a parental responsibility.

C.Most public health officials support some government involvement in nutrition policy.

D.Government efforts to reduce smoking rates in the U.S. have been quite effective.

 

First step: go to the part of the passage where the relevant portion is discussed. Now, what is the author’s conclusion? It’s this:

The best thing that the U.S. government can do to promote health is to encourage people to develop their own individually-tailored diet and exercise programs, in consultation with health-care professionals. Otherwise, public health medicine risks violating the central principle of medical ethics: First, do no harm.”

The conclusion is that people should do their own thing, and doing your own thing makes people healthy. So, to support that, let’s make sure that making people do their own thing is actually a good idea. A and C actually have literally zero to do with that (A is an opinion, and C doesn’t matter).

D goes against it, and suggests that it’s a good thing when government intervenes. Let’s avoid that, because the author is totally against the government.

That leaves us with B. It’s not perfect, because it talks about parents (instead of individuals), but it’s a lot better than our other options. This is true of a lot of CARS questions: the correct answer isn’t perfect, but it’s better.

 

Inference questions

-Inference questions are like detail questions, but normally require some aspect of Critical Reasoning afterwards

-You can tell an inference question if it looks like a detail question with something more

 

Which of the following criticisms of a proposed space shuttle flight is most like that of the “major scientific dissenters” (paragraph 6), as the author presents their views?

A.The composition of the shuttle crew violates equal rights legislation.

B.The shuttle flight is motivated mostly by political objectives.

C.The shuttle assembly has serious design flaws.

D.The shuttle flight costs too many taxpayer dollars.

 

We know exactly where to go here. It’s to paragraph 6. Let’s figure out exactly why the dissenters are mad.

 

Supporters of the guidelines have increasingly struggled to justify them, sometimes resorting to political arguments. Without clear dietary guidelines, they claim, the food industry and other special interests could lobby political leaders and influence policy in unhealthy ways. But this argument makes sense only if you assume that the government’s guidelines will be any healthier. Supporters also argue that the government’s success in persuading people to stop smoking, equally paternalistic, justifies its efforts to change American eating habits. [But the major scientific dissenters from government dietary policy are not especially concerned with governmental paternalism, though that is a legitimate issue. They dissent because they find the government’s evidence inadequate and its recommendations potentially harmful.]

 

Through careful reading, we zone in on the part that explains exactly why they’re mad. To this extent, this is just a detail question. They’re mad because there’s not great evidence, and this means that the recommendation could result in bad stuff happening.

Now it’s time for Critical Reasoning, based on the information we have so far. Comparing our analysis to the actual answer choices, I don’t love any of the answers. However, let’s see what we can rule out. What’s most similar to bad evidence possibly hurting people?

Well, it’s not concerns about money, legislation, or political motivation. None of those involve possibly hurting people. If they mess up a space shuttle’s designs, though, it’s possible it could blow up. That would definitely hurt people. So C. Still not a great answer, but not a bad one either.

Conclusion

That’s it for my abbreviated CARS strategy guide. If you’re interested in a full strategy guide, with a bunch more examples, click here.

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