Test the connection between evidence and conclusion, using relevant alternatives rather than general skepticism.
GRE General Test45 min study guide10 indexed sections
BY THE END, YOU CAN
Separate premises from a conclusion.
Choose evidence that strengthens or weakens the actual inference.
Evaluate alternative causes and sampling problems.
Explain why a true but irrelevant statement does not change an argument.
BEFORE YOU START
Understand correlation versus causation.
Recognize populations, samples and comparison groups.
Original educational lesson. Work through the examples before revealing the practice answers. This original lesson supports current GRE General Test study; it does not reproduce official questions, certify a writing score or predict test content.
LEARN THROUGH ORIGINAL PRACTICE
Original GRE-style worked examples and practice
All teaching passages, writing prompts, examples and exercises in this lesson are original. No official ETS questions, prompts or explanations are reproduced. Current structure and observed public sample metadata are separate from this original teaching; no official score or question probability is implied.
01 / UNDERSTAND & APPLY
Identify the claim before testing its support
An argument offers reasons for accepting a conclusion. First state the conclusion with its degree of certainty: “may contribute” differs from “is the sole cause.” Next identify the evidence offered. The vulnerable point is often the connection between them: the data are accepted, but the inference goes further than the data alone justify.
This lesson concerns evaluating arguments within Verbal Reasoning. It does not present the retired Analyze an Argument writing task as a current GRE task. All examples, passages and exercises are original educational material.
ORIGINAL WORKED EXAMPLE
Locate the inference
Original argument: After the town added bicycle lanes, bicycle counts at the central bridge increased. The lanes therefore caused the increase. Identify evidence and conclusion.
Evidence: counts increased after lane installation.
Conclusion: lane installation caused the increase.
The bridge counts and temporal order can be true even if another change contributed.
Evaluation should target the causal connection, not merely repeat the observed increase.
Answer The evidence is a before/after association; the conclusion attributes the change to the lanes.
02 / UNDERSTAND & APPLY
Change support without demanding proof
A strengthening fact makes the conclusion more credible relative to the premises; it need not prove it. A weakening fact reduces that support; it need not establish that the conclusion is false. A conclusion can remain plausible after a good objection, especially if the original claim was modest.
Take proposed new information as true within the exercise, then ask how it bears on the gap. Do not reject an option because the new fact was absent from the original passage: supplying relevant new information is the point of this task. Irrelevant facts do not help merely because they concern the same topic.
ORIGINAL WORKED EXAMPLE
A competing explanation
Using the original bicycle-lane argument, select one strongest weakening fact: A The bridge was painted blue; B During the same period, a nearby bridge closed and diverted cyclists to the central bridge; C Some residents like cycling; D The lanes were publicly announced; E The town has a long history.
The conclusion concerns why counts at this bridge increased.
A bridge closure supplies a direct alternative cause: redistribution of existing cyclists.
B allows higher counts without an increase caused by the new lanes.
A, C, D and E do not specifically explain the measured change.
Answer B.
03 / UNDERSTAND & APPLY
Distinguish three common causal gaps
A third factor can influence both the supposed cause and the outcome. Reverse causation occurs when the outcome helps produce what was treated as the cause. Selection effects occur when the groups differ before treatment: people choosing a program may already be more motivated.
A before/after comparison can also be distorted by a concurrent change or seasonal pattern. The best alternative explanation fits the observed timing, groups and outcome. “Anything could happen” is not an argument; identify a specific pathway that the evidence fails to exclude.
ORIGINAL WORKED EXAMPLE
Selection into a program
Original argument: Employees who volunteered for a training course received more promotions than nonparticipants. The course must improve promotion prospects. Select one strongest weakening fact: A Participants had higher performance ratings before the course; B The course had a printed handbook; C Promotions are announced in June; D Most employees own computers; E The course room had windows.
The course was voluntary, so groups may differ at baseline.
A identifies a prior difference plausibly related to promotion.
This weakens attribution of the later difference to training.
It does not prove the course has no benefit; it shows the comparison cannot isolate it.
Answer A.
04 / UNDERSTAND & APPLY
Check what a measure actually measures
Measurement validity asks whether the recorded variable matches the conclusion’s concept. Downloads are not necessarily readers; complaints are not necessarily all defects; detected cases are not necessarily all cases. Changes in detection, recording or denominators can change the measure without the underlying phenomenon changing in the same way.
Sampling quality concerns who was observed and who was missed. A large sample can still be biased if it systematically excludes a relevant group. Precision within a biased sample does not automatically justify generalization to the target population.
ORIGINAL WORKED EXAMPLE
Counts versus underlying incidence
Original argument: Recorded equipment faults doubled after a new reporting app launched. The equipment must have become less reliable. Select one strongest weakening fact: A The app made previously unreported minor faults easy to record; B Equipment is expensive; C Staff prefer short forms; D The app icon is green; E Reliability matters.
The evidence concerns recorded faults, while the conclusion concerns underlying reliability.
A changes the probability that an existing fault is recorded.
The same equipment performance could produce more records under more complete reporting.
C might sound relevant, but A directly identifies the measurement mechanism.
Answer A.
05 / UNDERSTAND & APPLY
What makes a comparison more informative?
A relevant comparison can reduce alternative explanations when groups are alike in important respects, outcomes are measured consistently, and timing aligns with the proposed effect. Random assignment can help balance preexisting differences, but it does not automatically solve attrition, noncompliance or poor measurement.
For a verbal question, you rarely need to design an entire study. Identify the proposed fact that most directly closes the stated gap. Evidence that eliminates one alternative strengthens a causal interpretation without proving every alternative false.
ORIGINAL WORKED EXAMPLE
A targeted strengthening fact
Original argument: A revised packaging method reduced breakage during transport. Evidence: shipments using the new method had fewer broken items. Select one strongest supporting fact: A The old method was unpopular; B Comparable items were randomly assigned to the two methods and shipped on the same routes during the same period; C The new packages look attractive; D Some breakage is inevitable; E Drivers noticed the labels.
The key concern is whether shipment conditions or item fragility differ.
B reduces these alternative explanations through comparable items, random assignment and shared conditions.
A and C concern preference or appearance rather than breakage; D does not identify an effect; E has no specified causal relevance.
Even B supports rather than guarantees the conclusion.
Answer B.
06 / UNDERSTAND & APPLY
Map evidence, bridge and alternative
The diagram shows two pathways to a higher recorded count. The argument favors one pathway, but a measurement change can produce the same observation. Weakening evidence is powerful when it supports that rival pathway while leaving the observed count intact.
This is a conceptual diagram, not a quantified model. Arrow direction expresses a proposed explanation. The presence of an arrow does not establish that the relationship occurs in a real case.
Full-size scientific diagram. Swipe or scroll horizontally; keyboard users can focus the diagram and use arrow keys.
Conceptual argument map: proposed causal paths, not measured effects or proof that either path occurred.
07 / UNDERSTAND & APPLY
Original practice: target the gap
Choose exactly one strongest answer unless otherwise specified.
ORIGINAL PRACTICE · 1
Original argument: Students using a study app earned higher grades, so the app caused improvement. Best weakening fact: A App users already had higher grades before adopting it; B The app uses blue text; C Some users own headphones.
Reveal answer & reasoning
A.
A identifies preexisting achievement differences that can explain the observed association. The other facts do not bear on the causal inference.
ORIGINAL PRACTICE · 2
Original argument: Fewer complaints show that service improved. Best weakening fact: A The complaint portal was unavailable for half the month; B Staff wore new uniforms; C The building was repainted.
Reveal answer & reasoning
A.
The evidence depends on complaints being observable. Reduced access can lower recorded complaints independently of service quality.
ORIGINAL PRACTICE · 3
Original argument: A museum’s online poll shows most residents favor longer evening hours. The poll was advertised only in the evening-visitors newsletter. Identify the principal concern.
Reveal answer & reasoning
The respondents may disproportionately represent people already interested in evening visits.
The sampling route can bias preferences even if many people respond. The criticism concerns representativeness, not whether each response is honest.
ORIGINAL PRACTICE · 4
Original argument: A town’s water use declined after a price increase, so the increase caused the decline. Best weakening fact: A The same period brought unusually heavy rain that reduced garden watering; B Bills were printed monthly; C Water meters are metal.
Reveal answer & reasoning
A.
Rain supplies a time-matched alternative explanation for reduced use. The other facts do not explain the change.
08 / UNDERSTAND & APPLY
Original practice: relevance and degree
Evaluate whether the new evidence affects the stated inference, not merely whether it sounds favorable.
ORIGINAL PRACTICE · 1
Original argument: Shade cloth lowered plant water loss. Select one strengthening fact: A Matched plants under identical conditions differed only in use of the cloth; B The cloth was cheap; C Gardeners liked its color.
Reveal answer & reasoning
A.
A reduces differences in plant type and growing conditions as alternative causes. Price and appearance do not establish water-loss effects.
ORIGINAL PRACTICE · 2
Original argument: A translation’s unusual phrase reflects direct influence from an earlier work. Select one strengthening fact: A A dated notebook shows the translator copied and discussed that phrase before composing the translation; B Both books are long; C The phrase is grammatically possible.
Reveal answer & reasoning
A.
The notebook supplies specific access and attention before composition, making influence more plausible. It does not necessarily prove the precise mental process.
ORIGINAL PRACTICE · 3
Original argument: Because attendance rose after free entry began, free entry was the sole cause. New fact: a popular temporary exhibition opened simultaneously. Does it weaken the conclusion, and does it prove free entry had no effect?
Reveal answer & reasoning
It weakens the sole-cause claim but does not prove that free entry had no effect.
A plausible concurrent contributor challenges exclusivity. Multiple causes can operate together.
ORIGINAL PRACTICE · 4
Original argument: The new map is more accurate because it includes more place names. What information would be most useful to evaluate the inference?
Reveal answer & reasoning
Whether the added names and locations are correct, and whether accuracy of other mapped features is comparable.
More entries increase detail, not necessarily correctness. The useful evidence must connect quantity of information to accuracy rather than merely confirm a larger label count.
09 / UNDERSTAND & APPLY
Developed original passage: integrate the full argument
The following passage and question are original educational material. Read the whole passage before answering; the five options deliberately differ in scope, attribution or argumentative role.
A regional transit office tested a new sign system at three busy stations. During the month after installation, staff recorded fewer requests for directions than during the previous month. The office concluded that the signs had made navigation easier and proposed installing them throughout the network. The proposal noted that the trial stations handled a large number of passengers, so even a modest reduction in confusion could save substantial staff time.
The recorded requests are relevant to navigation, but their interpretation depends on how passengers could obtain help in the two periods. During the trial, the stations also introduced an information desk operated by temporary volunteers. Questions answered at that desk were not entered in the staff reporting system. Passenger volumes were similar in the two months, and no major service changes occurred. The trial therefore leaves an important question unresolved: did passengers need less assistance, or did the new desk simply move some requests outside the measured channel? A decision about network-wide signs should distinguish these possibilities.
ORIGINAL WORKED EXAMPLE
A complete-passage worked analysis
Select exactly one finding that would most strengthen the claim that the signs reduced confusion: A Volunteers wore bright uniforms. B Station managers liked the appearance of the signs. C The combined number of navigation requests to staff and volunteers fell substantially, using consistent definitions and comparable passenger volumes. D The sign supplier offered a discount for large orders. E The three stations are older than most stations in the network.
The passage identifies a measurement gap: staff-only records exclude the new help desk.
C closes that gap by combining both channels and maintaining comparable definitions and volumes.
A lower combined request count supports reduced assistance needs more directly than a change in channel alone.
A and B concern visibility or preference without linking to total confusion; D concerns cost, not effect; E gives age without an explanatory connection.
C strengthens the navigation inference, but other questions about unrecorded help or wider network transfer can remain.
Answer C.
10 / UNDERSTAND & APPLY
Explain the mechanism of relevance
A good answer explanation names the gap and shows how the new fact changes it. “This weakens the argument” is a label, not reasoning. Complete the sentence: “Even if the evidence is true, this fact makes it possible that…” or “This fact makes the comparison more informative because…”.
During review, separate the argument’s truth from the adequacy of its support. You may personally believe the conclusion, but the question can still ask which evidence weakens its stated justification. Conversely, a strengthening fact need not remove all uncertainty.
KEEP THE BIG IDEAS
Quick revision
Evaluate the connection between evidence and the precise conclusion.
Strengthen and weaken are changes in support, not demands for proof or disproof.
Look for confounding, reverse causation, selection and measurement changes.
A relevant alternative explanation accounts for the actual observation.
The teaching notes, passages, worked explanations and practice are original. Official references identify the assessment framework and skill scope; they do not endorse this lesson or license official question reproduction.
GRE analytics distinguish current test structure from a small independently classified public sample selection. Writing instruction has no observed prompt-frequency denominator. These are not historical administered-exam frequencies.