The analytical section contains a small, highly predictable family of questions about causes: a claim that one thing produces another, and a task to strengthen, weaken or evaluate it. The reasoning is the same as critical reasoning, but the answer almost always turns on the single distinction the section loves most: two things moving together is not proof that one moves the other.
These questions are fair. They never require specialist knowledge; they require you to notice that a third factor, a reversed order, or a coincidence can explain the evidence just as well as the stated cause.
A causal claim needs three supports. Remove any one and the claim weakens.
The model's missing piece: the test rarely asks you to prove causation. It asks which option makes the causal claim more or less credible. So you look for the option that supplies a mechanism or removes a rival explanation; that is the strengthener. The option that supplies a rival explanation is the weakener.
| Relationship | Example | How to weaken the stated cause |
|---|---|---|
| A causes B (as claimed) | Smoking causes lung damage | Hard to weaken; look for a confound the study missed |
| B causes A (reversed) | Lung damage causes smoking | Show the effect precedes the supposed cause |
| C causes both (common cause) | Stress causes both smoking and illness | Name the third factor that drives both |
| Coincidence | Two unrelated trends | Show the association is spurious or disappears with more data |
Cities that employ more firefighters also record more fire damage. The author concludes that the firefighters cause the damage. Which statement most weakens the conclusion?
The evidence is a correlation and the conclusion is causal. More fires in a city lead both to more firefighters being deployed and to more damage, so the common factor — the frequency and size of fires — explains the association without any firefighter causing anything. The strong weakener is: "larger cities have more fires, and both larger fire crews and greater damage follow from those fires."
Note why the tempting option "some firefighters are poorly trained" is wrong: it attacks a peripheral detail rather than the logical link, and it does not explain the correlation. Weakeners must break the causal argument, not merely introduce doubt.
Ice-cream sales and drowning deaths rise together every summer. What is the flaw in concluding that ice cream causes drowning?
Which observation would most strengthen the claim that a new study app improves exam scores?
"Since" and "therefore" appear in a causal claim. Which is the conclusion?
Without looking back: state the three supports a causal claim needs, and name the relationship that exists when a third factor drives both quantities.
A causal claim needs association, correct time order, and no better explanation. A third factor driving both is called a common cause.
Two quantities that move together are said to . If a hidden factor drives both, that factor is a . If the effect actually produces the supposed cause, the relationship is .
A study reports that employees who take more sick days are promoted less often, and concludes that sick leave damages careers. Give the most plausible alternative explanation and state what evidence would settle the question.
The alternative is a common cause: poor health, or a demanding role, can independently reduce attendance and reduce promotion chances. A second alternative is reversed causation at the level of commitment: employees already planning to leave take more leave and are passed over.
The evidence that would settle it: a controlled design that compares employees with similar health and similar roles, so that sick leave varies for reasons unrelated to those factors, and measures promotion separately. If promotion gaps persist, the causal claim survives; if they disappear, common cause or reversal better explains the data.
You can now separate a causal claim from a mere association. The next lesson moves from evaluating arguments to building them: taking a set of ordering and grouping rules and deducing exactly what must follow, the formal core of the analytical section.