Published by Think Clearly Prep · Updated .
Find the gap before judging choices
Start with the conclusion, then identify the evidence offered for it. The gap is what would need to be true for that evidence to justify the conclusion. A choice that sounds important in ordinary life may do nothing to this particular inference.
Example: A shop extended its hours, and monthly sales increased. The owner concludes that longer hours caused the increase. The gap concerns whether the schedule change, rather than something else, explains the higher sales.
Compare three new facts
The first fact does not prove longer hours contributed nothing. The second does not rule out every possible confounder. The relevant difference is the direction in which each fact changes the support.
- “A nearby competing shop closed during the same month.” This weakens the causal inference by supplying an alternative explanation.
- “Comparable shops with unchanged hours had stable sales, and the extra sales occurred during the newly added hours.” This strengthens the proposed explanation, although it does not prove it.
- “The owner prefers working in the evening.” This is largely irrelevant to whether extended hours caused the sales increase.
Watch the denominator
A service reports 20 complaints this year and 10 last year, then concludes that its quality deteriorated. If customers rose from 100 to 1,000, the complaint rate fell from 10% to 2%. That information weakens an inference drawn from raw counts alone.
A falling complaint rate does not establish that every aspect of quality improved. Customers may differ in willingness to complain. On an argument question, use the new fact to evaluate the specific reasoning instead of replacing it with a stronger unsupported claim.
Survey conclusions need a relevant sample
Suppose a city surveys people at a cycling club and finds that most favor building a bike lane. It concludes that most residents favor the project. Evidence that club members are more likely than other residents to favor bike lanes weakens the generalization. Evidence that a representative citywide sample produced a similar result would strengthen it.
Read the population named in the conclusion. A survey could be perfectly adequate for describing club members and inadequate for describing all residents. The same evidence changes significance when the conclusion’s scope changes.
Practice: choose the direction of effect
Argument: A school introduced a new attendance reminder, and absences declined. Therefore the reminder reduced absences. New fact: During the comparison period, the school also ended a transport disruption that had kept students home.
This weakens the argument by offering an alternative cause. It does not establish that reminders are useless. A different fact—attendance improved only among otherwise similar students receiving the reminder—would provide stronger support for the reminder explanation.
Avoid common traps
- Do not attack a premise when the stem asks you to accept the choices as new information. Work with the stimulus and the question’s instructions.
- Do not choose an emotional or impressive statement that leaves the evidence–conclusion link unchanged.
- Check whether the choice affects the same population, outcome, and time period.
- Distinguish a fact that weakens the conclusion’s support from one that merely makes the conclusion less desirable.