Rank 12 by frequency | 38 questions in corpus (1.5% of all questions)
Asks the test-taker to identify a statement that, if true, would most support, bolster, or provide evidence for an argument, claim, or theory presented in the passage. This is the mirror image of Weaken — both use "if true" hypothetical framing, but Strengthen looks for what makes the argument more convincing rather than less.
Strengthen has 4 distinct subtypes:
The dominant phrasing. - "Which one of the following, if true, would most support [X]?" - "Which one of the following provides the most support for [person]'s principal conclusion?" - "Which one of the following, if true, would most strengthen the passage's position concerning [X]?" - "Which one of the following, if true, would most strengthen the author's argument?"
What makes it distinct: Direct strengthen language. "Support" and "strengthen" are the operative words.
Uses stronger support language. - "Which one of the following, if true, would cast doubt on passage B but bolster the argument in passage A?"
What makes it distinct: "Bolster" implies more active reinforcement. Rare variant, sometimes appears in comparative passages where strengthening one passage's argument simultaneously weakens the other's.
Frames the task as finding evidence. - "Which one of the following, if true, would best serve as supporting evidence for [X]?" - "Which one of the following is evidence that would contribute to the 'proof' mentioned in [X]?"
What makes it distinct: Focuses on evidence rather than logical support — the answer should be a findable fact rather than an abstract logical prop.
Various phrasings: - "Which one of the following, if true, would most help to strengthen the author's main claim?" - "Which one of the following, if true, would lend the most credence to [X]?" - "Which one of the following studies would provide support for [person]'s claims?" - "The author would consider the explanation more favorably if it were shown that..."
Like Weaken, RC Strengthen questions target a specific argument or claim within the passage — usually not the main point but a sub-argument in one section. Common targets: - A scientific hypothesis or explanation - A historical analysis or interpretation - A causal claim ("X led to Y") - A prediction ("If we do X, then Y will happen") - A comparative evaluation ("Method A is better than Method B")
Every argument has logical gaps that additional evidence could fill: - Missing link: The argument claims X causes Y but doesn't explain the mechanism - Limited evidence: The argument cites some evidence but not enough for certainty - Unstated assumption: The argument assumes something it doesn't prove - Alternative explanation concern: The argument could be explained differently - Scope question: Does the argument apply broadly, as claimed?
The correct answer provides hypothetical evidence that fills the most critical gap: - Must be external to the passage (new information) - Must directly support the targeted claim - Must address a genuine vulnerability in the argument - Must be the most strengthening option among the five choices
Common strengthening patterns: - Confirming the mechanism: If the argument claims X causes Y, evidence showing how X produces Y strengthens it - Eliminating alternatives: Evidence ruling out competing explanations - Extending the evidence base: Additional observations consistent with the prediction - Supporting an assumption: Evidence confirming a key unstated premise - Analogous case: A similar situation where the same mechanism produced the predicted result
Trap Type 1: Irrelevant Information Relates to the topic but doesn't actually support the specific argument. May sound relevant because it uses passage vocabulary.
Trap Type 2: Actually Weakens Provides evidence that undermines rather than supports the argument. Catches test-takers who confuse the direction.
Average 22.5 words. Very similar to Weaken in construction — often nearly identical except for the direction word ("strengthen" vs. "weaken," "support" vs. "undermine").
Average 20.4 words. Hypothetical evidence or findings. Each answer is a self-contained factual claim.
Key pattern: The correct answer often fills the most critical logical gap in the argument — not just any gap, but the one whose resolution most increases confidence in the conclusion.
Source: PT32, Q23 > "Which one of the following, if true, would most strengthen the passage's position concerning the apparently healthful effects of moderate wine consumption?"
Correct Answer (A): "Subjects who consumed large amounts of grape juice exhibited decreased thickness of the innermost walls of their blood vessels."
Source: PT80, Q13 > "Which one of the following, if true, would provide the most support for the authors' analysis of the Great Migration?"
Correct Answer (B): "In general, communities of African Americans in the North consisted largely of individuals who shared a common geographic place of origin in the South."
Source: PT90, Q3 > "Which one of the following would, if true, most strengthen the author's position regarding the risks of deep-well injection of hazardous wastes?"
Correct Answer (D): "The movement of underground water is even more rapid and less predictable than most geologists believe."