Parallel Reasoning
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LSAT Logical Reasoning › Parallel Reasoning
Which of the following most closely parallels the reasoning in the argument above?
Most effective reforms secure early commitments; this reform secured early commitments, so it is probably effective.
Securing early commitments guarantees effectiveness; this reform secured early commitments, so it is ethical.
Every effective reform secures early commitments; this reform did not secure early commitments, so it will not be effective.
Only reforms with early commitments can be effective; this reform is not effective, so it must not have had early commitments.
All top-tier chefs apprentice in demanding kitchens first. Milo apprenticed in such a kitchen, so Milo is a top-tier chef.
Explanation
The original infers membership in a group (effective reforms) from possessing a condition all group members have (early commitments), which is the converse error. Choice E mirrors that structure by inferring top-tier status from a trait all top-tier chefs share. The other choices alter quantifiers, draw valid contrapositives, or shift the conclusion to a different attribute.
Which of the following most closely parallels the flawed reasoning in the argument above?
A neighborhood group asked only midday park visitors about safety; responses were positive; therefore, the park is safest at night.
A theater polled season ticket holders and found high satisfaction with seat location; therefore, seat location is not a factor for casual attendees.
A tech firm asked all employees about the cafeteria and found most wanted longer hours; therefore, employees generally want longer hours.
The library collected comment cards at the downtown branch, which serves the widest cross-section of patrons; most praised late hours; thus, patrons generally prefer later hours.
An online retailer measured satisfaction with delivery speed by sending a survey only to customers who paid for express shipping; responses showed high satisfaction; thus, customers overall are satisfied with delivery speed. Express orders, of course, arrive fastest.
Explanation
Both arguments generalize from a sample selected precisely for having better conditions (first-class/express) to conclude overall satisfaction, with a note highlighting the favorable condition. A and E describe more representative sampling. C draws a conclusion about a different time than the surveyed group, and D draws a conclusion about a different population.
Which of the following most closely parallels the reasoning employed in the argument?
If the new streetlights deter burglars, we will eventually see fewer burglaries. Burglaries are fewer now, so the lights deter burglars.
Because crime fell right after the lights were installed, the lights caused the decline.
Since crime fell citywide, it must have been caused by something the city did.
Crime did not fall in the suburbs, so the city must not have changed its policing strategies.
If the new streetlights were responsible for the citywide drop in crime, suburbs that also installed them would see similar drops. Crime did not fall there, so the lights were not the cause.
Explanation
The passage uses a conditional prediction and, when the predicted effect is absent in a comparable case, denies the proposed cause. Choice A mirrors that conditional structure and inference pattern. The other options either affirm the consequent (B), make unsupported causal claims (C and E), or state a trivial causality without the conditional test (D).
Which of the following most closely parallels the reasoning in the argument above?
All graduate students attend orientation. Many who attend orientation receive campus tours. Therefore, all graduate students receive campus tours.
Most graduate students attend orientation. Many who attend orientation receive campus tours. Therefore, many graduate students receive campus tours.
All graduate students attend orientation. Many who attend orientation receive campus tours. Therefore, many graduate students receive campus tours.
All graduate students attend orientation. Many graduate students receive campus tours. Therefore, many who attend orientation receive campus tours.
All graduate students attend orientation. Many who attend orientation receive campus tours. Therefore, at least some graduate students receive campus tours.
Explanation
The passage moves from 'All A are B' and 'Many B are C' to 'Many A are C,' which need not follow. Choice A exactly parallels that flawed quantifier inference. The other options either change the quantifiers or weaken/strengthen the conclusion so the structure no longer matches.
At Pinecrest University, the administration notes that in departments where at least 80% of faculty attend the new teaching workshops, student course evaluations improved the following semester. The administration also notes that the history department’s evaluations improved last semester. Therefore, the administration concludes that at least 80% of history faculty must have attended the workshops. Since workshop attendance is voluntary, the administration further concludes that history faculty must have been especially motivated to improve their teaching compared with faculty in other departments.
If a restaurant uses fresher ingredients, customer complaints decrease. Complaints decreased at a restaurant, so it must have used fresher ingredients. Since fresh ingredients cost more, the restaurant must have raised its prices.
Whenever a neighborhood installs brighter streetlights, nighttime crime decreases. Nighttime crime decreased in Oakview, so Oakview must have installed brighter streetlights. Therefore, Oakview residents must have petitioned the city for months to get the lights installed.
Whenever a city increases the number of traffic cameras, the number of speeding tickets issued rises the next month. Last month, speeding tickets rose in Brookdale. So Brookdale must have increased traffic cameras. Since installing cameras is optional, Brookdale’s officials must have been especially concerned about speeding compared with officials in other cities.
Whenever a museum extends its hours, attendance rises the next week. Attendance at the museum rose last week, so it must have extended its hours. Since extending hours requires extra staffing, the museum must have had fewer visitors than usual earlier in the month.
If a company offers employees a bonus, employee retention rises the next quarter. A company’s retention rose last quarter, so it must have offered a bonus. But because bonuses are expensive, the company must have been more profitable than its competitors.
Explanation
This argument commits the logical fallacy of affirming the consequent. The original argument establishes that 80% faculty attendance leads to improved evaluations, then observes improved evaluations and concludes that 80% must have attended. This reverses the conditional logic—the fact that A leads to B doesn't mean B proves A occurred. The correct answer (A) mirrors this exact structure: traffic cameras lead to more tickets, tickets increased, therefore cameras must have been added, and since it's optional, officials must be especially concerned. Choice B fails to match because it lacks the crucial second inference about comparative motivation—it only concludes the company was "more profitable," which doesn't parallel the "especially motivated compared with faculty in other departments" reasoning. When tackling parallel reasoning questions, strip away the surface content and focus on the logical skeleton: does the answer choice make the same inferential moves in the same sequence?
A restaurant owner claims that switching to a new supplier improved food quality. Online ratings have increased, so fewer customers must be dissatisfied with the meals. If fewer customers are dissatisfied, then most customers must think the ingredients are fresher. Therefore, the new supplier improved food quality. The owner does not consider that the restaurant also launched a discount campaign that might have attracted more forgiving reviewers.
A publisher says a new editor improved a magazine. Since subscriptions rose, fewer readers must dislike the content. If fewer readers dislike it, most readers must find it more engaging. So the new editor improved the magazine, ignoring that the magazine was bundled with another popular one.
A homeowner says a new sprinkler system improved the lawn. Since the grass is greener, fewer patches must be dying. If fewer patches die, most of the lawn must be getting enough water. So the sprinkler system improved the lawn, even though the weather has been cooler and wetter.
A doctor claims a new medication is effective. Because symptoms decreased, the medication must be responsible. So the medication is effective. This ignores that many patients also changed diets.
A principal says a new attendance policy worked. Since absences fell, fewer students must be skipping class. If fewer students skip, most students must value school more. Therefore the new policy worked, overlooking that a flu outbreak ended this semester.
A mechanic argues that a new oil brand protects engines. Since fewer cars return with problems, the oil must be better. And if the oil is better, the shop will gain customers. Therefore the oil brand protects engines, even though the shop also replaced worn tools.
Explanation
This parallel reasoning question requires matching the logical structure of the restaurant owner's argument. The original follows this pattern: positive outcome (increased ratings) leads to fewer instances of a problem (dissatisfied customers), which means most people have a positive experience (think ingredients are fresher), concluding the new policy worked—while ignoring an alternative explanation (discount campaign). Choice A matches this structure perfectly: increased subscriptions means fewer readers dislike content, which means most find it engaging, so the new editor improved the magazine—ignoring the bundling with another popular magazine. Both arguments use the same "fewer negative, therefore most positive" reasoning chain while overlooking confounding factors. Choice D might appear similar since it involves a policy and overlooked factor, but it lacks the specific intermediate step of inferring that "most" have a positive experience. In parallel reasoning questions, focus on the argument's logical architecture rather than thematic similarities.
A restaurant consultant argues that whenever a restaurant simplifies its menu, kitchen errors decrease, and when kitchen errors decrease, online ratings rise. The consultant notes that a restaurant’s online ratings rose last month. Therefore, the consultant concludes that the restaurant must have simplified its menu. Since no franchise rule forced a menu change, the consultant concludes that the owner must have been more willing to make tough decisions than most restaurant owners.
If a restaurant simplifies its menu, online ratings rise. Ratings rose, so the restaurant must have simplified its menu. Since changes were optional, the owner must have hired a consultant.
If a restaurant simplifies its menu, errors decrease, and if errors decrease, ratings rise. Errors decreased, so the restaurant must have simplified its menu. Since it was optional, the owner was decisive.
Whenever online ratings rise, kitchen errors must have decreased. Ratings rose, so errors decreased. Therefore, the restaurant simplified its menu.
Whenever a restaurant simplifies its menu, errors decrease, and when errors decrease, ratings rise. The restaurant simplified its menu, so ratings rose. Therefore, the owner made tough decisions.
Whenever a hotel streamlines check-in, front-desk mistakes decrease, and when mistakes decrease, guest ratings rise. Ratings rose, so the hotel must have streamlined check-in. Since no chain policy required it, the manager must have been more willing to make tough decisions than most.
Explanation
The restaurant consultant's argument follows a two-step causal chain: menu simplification reduces kitchen errors, which increases online ratings. Observing increased ratings, the consultant concludes the menu was simplified, then infers the owner was more willing to make tough decisions since no franchise rule required it. Choice A perfectly mirrors this structure: streamlined check-in reduces front-desk mistakes, which increases guest ratings. Observing increased ratings, it concludes check-in was streamlined, then infers the manager was more willing to make tough decisions since no chain policy required it. The parallel includes the two-step operational causation, the logical fallacy of affirming through the chain, and the specific comparative judgment about willingness to make difficult decisions. Choice D breaks the parallel by observing the intermediate step (errors decreased) rather than working backward from the final outcome, missing the complete reasoning structure that defines this argument pattern.
A nonprofit director argues that a new fundraising email template increased donor engagement. More recipients clicked the donation link, so fewer recipients must be uninterested in the cause. If fewer recipients are uninterested, then most recipients must feel more connected to the nonprofit. Therefore, the new template increased engagement. The director overlooks that the email list was recently cleaned to remove inactive addresses, which could raise click rates without changing engagement.
A marketer says a new subject line increased engagement. Since more people opened the email, the message must be better. Therefore engagement increased, though the sender name changed.
A charity director says a new fundraising email increased engagement. Since more recipients clicked the donation link, fewer must be uninterested. If fewer are uninterested, most must feel more connected. So the template increased engagement, ignoring that inactive addresses were removed from the list.
A director says a new website increased engagement. Since fewer people unsubscribe, most must be satisfied. Therefore engagement increased, though unsubscribe links were hidden.
A campaign manager says a new slogan increased support. Since donations rose, most voters must like the slogan. Therefore support increased, even though a rival dropped out.
A fundraiser says a new brochure increased engagement. Since more people donate, fewer must be skeptical. If fewer are skeptical, most must trust the nonprofit. Therefore engagement increased, although a celebrity endorsed it.
Explanation
This parallel reasoning question requires matching the nonprofit director's logical structure. The original argument follows this pattern: positive outcome (more recipients clicked donation link) means fewer instances of problems (uninterested recipients), which indicates most people have positive connection (feel more connected), concluding the new template worked—while ignoring an alternative explanation (cleaned email list removing inactive addresses). Choice A perfectly parallels this structure: more clicked donation link means fewer uninterested recipients, which means most feel more connected, so the template increased engagement—ignoring that inactive addresses were removed from the list. Both arguments use identical reasoning chains from improved email metrics to conclusions about donor engagement while overlooking list management changes that could independently boost response rates. Choice D might appear similar with its engagement theme, but it involves unsubscription and hidden links rather than the specific "interest leading to connection" reasoning pattern. In parallel reasoning questions, the logical architecture takes precedence over fundraising context similarities.
A museum director argues that the new exhibit layout increased visitor satisfaction. Visitor complaints have dropped, so fewer visitors must be confused about where to go. If fewer visitors are confused, then most visitors must find the museum easier to navigate. Therefore, the new layout increased satisfaction. The director overlooks that the museum also reduced ticket prices, which may have influenced visitors expectations and willingness to complain.
A chef claims a new menu is better. Since more diners order desserts, the menu must be appealing. Therefore the new menu is better, even though the restaurant extended its hours.
A curator says a new lighting system improved art appreciation. Because visitors spend longer in galleries, the lighting must be more flattering. And if it is more flattering, visitors will buy more souvenirs. Therefore the lighting improved appreciation, although the gift shop expanded.
A transit official says a new bus schedule improved service. Since complaints decreased, fewer riders must be missing buses. If fewer riders miss buses, most riders must find the system easier to use. So the new schedule improved service, ignoring that fares were temporarily lowered.
A coach says a new playbook improved teamwork. Since fewer arguments occur, most players must respect each other more. So the playbook improved teamwork, even though two rival players were traded away.
A landlord argues that new hallway signs reduced noise. Since fewer tenants complain, the signs must have made people quieter. Therefore the signs reduced noise, though several noisy tenants moved out.
Explanation
This parallel reasoning question asks us to find an argument matching the museum director's logical structure. The original argument follows this pattern: positive outcome (fewer complaints) indicates fewer people having problems (confusion), which means most people have positive experiences (find navigation easier), concluding the new system worked—while ignoring an alternative explanation (reduced ticket prices). Choice A perfectly parallels this structure: fewer complaints means fewer riders miss buses, which means most find the system easier to use, so the schedule improved service—ignoring lowered fares. Both arguments use the same logical chain from reduced complaints to inferred satisfaction while overlooking external factors that could affect complaint rates. Choice D might seem appealing because it involves a conclusion about effectiveness despite an alternative factor, but it lacks the crucial intermediate reasoning about "most" people having positive experiences. When solving parallel reasoning questions, trace the logical steps rather than focusing on superficial content similarities.
A bookstore owner argues that the new store layout increased customer satisfaction. Returns decreased, so fewer customers must be buying the wrong books by mistake. If fewer customers buy the wrong books, then most customers must find the store easier to browse. Therefore, the new layout increased satisfaction. The owner ignores that the store also changed its return policy to be stricter, which could reduce returns without improving browsing.
A shop owner says a new sign improved sales. Since sales rose, fewer customers must be confused. Therefore the sign improved sales, even though prices dropped.
A manager claims a new refund policy improved profits. Since profits rose, fewer refunds must be issued. Therefore profits improved, though advertising increased.
A librarian says a new shelving system improved satisfaction. Since more books are borrowed, most patrons must like the system. Therefore satisfaction improved, though the library expanded hours.
A clothing retailer says a new floor plan increased customer satisfaction. Since returns fell, fewer customers must be choosing the wrong items by mistake. If fewer choose wrongly, most must find the store easier to browse. So the floor plan increased satisfaction, ignoring that the return policy became stricter.
A curator says a new exhibit order improved understanding. Since fewer visitors ask questions, fewer must be confused. If fewer are confused, most must understand. Therefore the order improved understanding, although guides were added.
Explanation
This parallel reasoning question asks us to identify an argument matching the bookstore owner's logical structure. The original follows this pattern: positive outcome (decreased returns) means fewer instances of customer errors (buying wrong books), which indicates most customers have improved experiences (find browsing easier), concluding the new layout worked—while ignoring an alternative explanation (stricter return policy). Choice A mirrors this structure exactly: fewer returns means fewer customers choose wrong items by mistake, which means most find the store easier to browse, so the floor plan increased satisfaction—ignoring a stricter return policy. Both arguments use the same logical progression from reduced returns to conclusions about customer experience while overlooking policy changes that could affect return rates independently of layout improvements. Choice E might seem appealing because it involves customer understanding, but it focuses on confusion and guides rather than the specific "wrong purchases leading to browsing ease" reasoning pattern. Effective parallel reasoning requires matching the argument's precise logical architecture.