CHAPTER 7: CAUSE AND EFFECT REASONING

• Cause and Effect reasoning asserts or denies that one thing causes another, or that one thing is caused by another

• Causality occurs when one event is said to make another occur. The cause is the event that makes the other occur, the effect is the event that follows from the cause

• Causality is the most tested logical concept in GMAT Critical Reasoning stimuli. Second most tested concept is numbers and percentages

The following terms often introduce a cause and effect relationship:

• caused by

• because of

• responsible for

• reason for

• leads to

• induced by

• promoted by

• determined by

• produced by

• product of

• played a role in

• was a factor in

• is an effect of

There are many alternate phrases that can introduce causality. Those phrases would all have the similar characteristic of suggesting that one event made another occur

Causality in the Conclusion vs Causality in the Premises

• If the causal statement is the conclusion, then the reasoning is flawed. If the causal statement is the premise, then the argument may be flawed, but not because of the causal statement

• Classic mistaken cause and effect reasoning we will refer to throughout the book occurs when a causal assertion is made in the conclusion, or the conclusion presumes a causal relationship

• If a causal claim is made in the premises, however, then no causal reasoning error exists in the argument (of course, the argument may be flawed in other ways). Makers of the GMAT tend to allow premises to go unchallenged

• It is considered acceptable for an author to begin his argument by stating a causal relationship and then continuing from there

Situations that can lead to errors of causality

• There are two scenarios that tend to lead to causal conclusions in Critical Reasoning questions:

  • One event occurs before another

    • When one event occurs before another event, many people fall into the trap of assuming that the first event caused the second event

  • Two (or more) events occur at the same time

    • When two events occur simultaneously, many people assume that one event caused the other.

    • While one event could have caused the other, the two events could be the result of a third event, or the two events could simply be correlated without one causing the other

• [UNRELATED] Positive correlation is a relationship where the two values move together.

• [UNRELATED] Negative correlation is one where the two values move in opposite directions, such as with age and eyesight (the older you get, the worse your eyesight gets)

• Understanding the assumption that is at the heart of a causal conclusion is essential to knowing why certain answers will be correct or incorrect

• When a GMAT speaker concludes that one occurrence caused another, that speaker also assumes that the stated cause is the only possible cause of the effect and that consequently the stated cause will always produce the effect

• In real world, we would tend to look at an argument like the one above and think that while the conclusion is possible, there are also other things that could cause the effect. This is not how GMAT views the relationship. When a GMAT speaker makes an argument like the one above, he or she believes that the only cause is the one stated in the conclusion and that there are no other causes that can create that particular effect

How to attack a Causal Conclusion?

• When you identify a causal relationship in the conclusion of a GMAT problem, immediately prepare to either weaken or strengthen the argument

• Attacking a cause and effect relationship in Weaken questions almost always consists of performing one of the following tasks:

  • Find an alternate cause for the stated effect

    • Because the author believes there is only one cause, identifying another cause weakens the conclusion

  • Show that even when the cause occurs, the effect does not occur

    • This type of answer often appears in the form of a counterexample.

    • Because the author believes that the case always produces the effect, any scenario where the cause occurs and the effect does not weakens the conclusion

  • Show that although the effect occurs, the cause did not occur

    • The type of answer also appears in the form of a counterexample

    • Because the author believes that the effect is always produced by the same cause, any scenario where the effect occurs and the cause does not weakens the conclusion

  • Show that the stated relationship is reversed

    • Showing that the relationship is backwards (claimed effect is actually the cause of the claimed cause) undermines the conclusion

  • Show that a statistical problem exists with the data used to make the causal statement

    • If the data used to make a causal statement are in error, then the validity of the causal claim is in question

CHAPTER REVIEW

• Causality occurs when one event is said to make another occur

• Cause is the event that makes the other occur, the effect is the event that follows from the cause

• Most causal conclusions are flawed because there can be alternate explanations for the stated relationships:

  • some other cause could account for the effect

  • some third event could have caused both the stated cause and effect

  • the situation may in fact be reversed; the events may be related but not causally

  • the entire occurrence could be the result of chance

• Causal statements can be used in the premise or the conclusion of an argument.

  • If the causal statement is the conclusion, then the reasoning is flawed.

  • If the causal statement is the premise, then the argument may be flawed, but not because of the causal statement

• There are two scenarios that tend to lead to causal conclusions in Critical Reasoning questions:

  • One event occurs before another

  • Two (or more) events occur at the same time

• When a GMAT speaker concludes that one occurrence caused another, that speaker also assumes that the stated cause is the only possible cause of the effect and that the stated cause will always produce the effect

• In Weaken questions, attacking a cause and effect relationship almost always consists of performing one of the following tasks:

  • Find an alternative cause for the stated effect

  • Show that even when the cause occurs, the effect does not occur

  • Show that although the effect occurs, the cause did not occur

  • Show that the stated relationship is in fact reversed

  • Show a statistical problem exists with the data used to make the causal statement