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Learn to identify the answer choice that most effectively supports a conclusion's logical foundation on the GRE.
The ability to evaluate and strengthen arguments has been a cornerstone of Western intellectual tradition since antiquity. The ancient Greeks recognized that persuasion required more than mere assertion—it demanded a structured chain of reasoning from evidence to conclusion. When the Graduate Record Examination (GRE) was first developed, its designers drew upon centuries of work in formal logic and informal reasoning to construct questions that assess a test-taker's capacity for critical analysis. Among the most frequently tested question types in the Verbal Reasoning section is the Strengthen the Argument question, which asks you to find the piece of information that would most bolster a given conclusion.
Understanding how to strengthen an argument is not merely a test-taking skill—it is a fundamental competency in academic research, professional decision-making, and civic discourse. The core question this lesson addresses is deceptively simple: Given a conclusion and its supporting evidence, which additional piece of information would make the conclusion more likely to be true? Answering this question demands that you first dissect an argument into its component parts, identify unstated assumptions, and then evaluate which new information shores up the logical bridge between evidence and conclusion.
Before you can strengthen an argument, you must be able to dissect one. Every GRE argument contains three essential components: the premises (the stated evidence or facts), the conclusion (the claim being advanced), and the assumption (the unstated logical link that must be true for the conclusion to follow from the premises). Strengthen questions target the assumption: they ask you to find the answer choice that supports or validates this hidden link. The following principles form the foundation of your approach.
As the diagram makes clear, the key to any strengthen question lies in the assumption—the unstated logical connection between the evidence presented and the claim drawn from it. The correct answer does not restate the premise or rephrase the conclusion; instead, it provides new information that makes the assumption more plausible. In the example shown, the premise establishes a temporal correlation (sales rose after the ad campaign), and the conclusion asserts causation (the ad campaign caused the rise). The gap—the assumption—is that nothing else could explain the increase. A correct strengthener eliminates one such alternative explanation: if no competitor ran a similar promotion, one potential confounding variable is removed, and the causal claim becomes more credible.
Although GRE strengthen questions do not involve mathematical formulas in the traditional sense, they do follow a rigorous logical structure that can be formalized. Understanding this structure at a deeper level will allow you to diagnose arguments more quickly and accurately. Most GRE arguments rely on inductive reasoning—they draw probable (not certain) conclusions from specific evidence. This means there is always an inferential gap that a strengthener can fill.
GRE arguments typically follow a handful of recurring logical patterns. Recognizing these patterns allows you to predict the type of strengthener the question demands. The first and most common is the causal argument, in which the author observes a correlation and concludes that one event caused another. To strengthen such an argument, you must rule out alternative causes, confirm that the cause preceded the effect, or show that removing the cause eliminates the effect. The second pattern is the analogy argument, in which the author draws a comparison between two situations and concludes that what is true of one must be true of the other. To strengthen an analogy argument, demonstrate that the two situations share the relevant features. The third pattern is the statistical/sampling argument, where a conclusion about a population is drawn from a sample. Strengtheners here confirm that the sample is representative.
Understanding the taxonomy of answer choices is essential for efficient and accurate performance on strengthen questions. On the GRE, answer choices for strengthen questions generally fall into one of several categories, and learning to classify them will dramatically improve your speed. Not every choice that seems positive toward the conclusion actually strengthens it; some are irrelevant distractors or even subtle weakeners. The following table breaks down the main types of answer choices you will encounter.
| Answer Type | Description | Example (for a causal argument) | Correct? |
|---|---|---|---|
| Eliminates Alternative | Removes a plausible alternative cause or explanation, making the stated cause more likely. | "No other marketing effort was underway during the same period." | ✓ Often correct |
| Confirms Mechanism | Provides evidence that the proposed mechanism actually operates as the argument claims. | "Customers surveyed cited the ad as their primary reason for purchasing." | ✓ Often correct |
| Broadens Evidence Base | Adds corroborating data or a parallel case that supports the conclusion. | "A similar ad campaign in another region also produced a 25% sales increase." | ✓ Sometimes correct |
| Restates Premise | Rephrases information already provided in the stimulus. Adds no new support. | "Sales figures increased significantly following the campaign's debut." | ✗ Trap answer |
| Out of Scope | Introduces information irrelevant to the specific logical gap in the argument. | "The company also expanded into international markets that year." | ✗ Trap answer |
| Weakener in Disguise | Sounds supportive but actually introduces an alternative explanation or undermines the assumption. | "The product received a major price reduction at the same time." | ✗ Trap answer |
Let us work through a complete GRE-style strengthen question using the systematic approach developed in the previous sections. Read the stimulus carefully, then follow each step.
The question asks: Which of the following, if true, most strengthens the argument?
Even well-prepared students can fall into predictable traps on strengthen questions. The GRE is designed to exploit systematic cognitive biases—tendencies to favor choices that feel intuitively satisfying but miss the logical point. The following table compares effective strategies with the common errors that lead to incorrect answers.
| Effective Strategy | Common Pitfall | Why the Pitfall Fails |
|---|---|---|
| Target the assumption, not the conclusion | Choosing an answer that simply agrees with the conclusion | Agreeing with the conclusion is not the same as supporting the reasoning. A strengthener must address the logical gap, not just sound positive. |
| Pre-phrase before reading choices | Reading all choices first and being swayed by emotionally appealing language | Without a prediction, you become susceptible to choices that use the same vocabulary as the stimulus but fail to address the gap. |
| Apply the denial test to close calls | Picking the first answer that "sounds right" | The denial test provides an objective criterion: the choice whose negation most damages the argument is the strongest strengthener. |
| Distinguish between necessary and sufficient strengtheners | Demanding that the answer "prove" the conclusion | A strengthener only needs to make the conclusion more likely—not certain. Even incremental support is sufficient if it best addresses the gap. |
| Stay within the argument's scope | Selecting an answer that introduces new, tangential information | Even interesting or true information that does not connect to the specific assumption cannot strengthen the specific argument at hand. |
Strengthen questions do not exist in isolation; they are part of a family of argument-based question types on the GRE, and mastering one builds transferable skills for the others. The analytical framework you use for strengthen questions—identify conclusion, isolate premises, uncover assumption—is identical for weaken, assumption, and evaluate questions. The only difference lies in what you do with the assumption once you find it. Understanding these relationships will make you a more versatile and efficient test-taker.
| Question Type | What It Asks | Relationship to the Assumption | Key Difference from Strengthen |
|---|---|---|---|
| Strengthen | Find information that makes the conclusion more likely | Supports or validates the assumption | This is the baseline |
| Weaken | Find information that makes the conclusion less likely | Attacks or undermines the assumption | Mirror image: same skill, opposite direction. If you can strengthen, you can weaken. |
| Identify Assumption | State what must be true for the conclusion to hold | Is the assumption itself | The answer to an assumption question is what you use to predict the answer to a strengthen question. |
| Evaluate | Identify a question whose answer would help determine the argument's strength | Tests whether the assumption holds | Instead of providing the supporting fact, you identify what question would need to be answered. |
| Inference / Must Be True | Determine what logically follows from the stated information | No assumption to find—premises are treated as complete | Different skill entirely: deductive rather than evaluative. No gap to fill. |
The skill you develop in strengthen questions also transfers directly to the Analytical Writing section of the GRE, specifically the "Analyze an Argument" essay task. In that task, you must dissect an argument's logical structure, identify its assumptions, and explain how additional evidence could strengthen or weaken the author's reasoning. The vocabulary and framework you learn here—premises, conclusions, assumptions, confounding variables, causal vs. correlational reasoning—directly equips you for that essay.
GRE Strengthen the Argument questions require you to find the answer choice that makes a conclusion more likely to be true. Every argument has three components: premises (stated evidence), a conclusion (the author's claim), and an assumption (the unstated logical bridge). The correct answer always targets and supports the assumption, not the premise or the conclusion itself. The three most common argument patterns are causal (correlation presented as causation), analogy (comparison between two situations), and statistical (sample-to-population generalizations).
Your systematic approach should follow five steps: (1) identify the conclusion using signal words like "therefore" and "thus"; (2) isolate the premises; (3) uncover the assumption by asking what must be true for the conclusion to follow; (4) pre-phrase a prediction before reading the answer choices; and (5) evaluate choices using the denial test—negate each option and check whether the argument collapses. Watch for trap answers that restate the premise, introduce irrelevant information, or subtly weaken the argument. These skills transfer directly to weaken, assumption, and evaluate question types, as well as to the Analytical Writing section.