Rank 12 by frequency | 38 questions in corpus (1.5% of all questions)
Strengthen questions ask you to find a statement that, if true, would most support an argument, claim, or theory that appears inside the passage. Unlike its Logical Reasoning cousin, which operates on a short standalone argument, RC Strengthen operates on an argument embedded in a longer text — you first have to locate the targeted position inside the passage, then evaluate which hypothetical new fact most bolsters it.
A Strengthen stem hands you a hypothetical: if the following were true, which would most support the passage's argument? You are not evaluating what the passage already says — you are evaluating five brand-new pieces of information from outside the passage and asking which one, if added, most increases confidence in the targeted claim.
The skill being tested is gap identification: seeing what the argument needs, what vulnerability it has, and what kind of outside evidence would patch it. You also need direction sensitivity — distinguishing between evidence that supports a claim and evidence that merely sits near the topic, or worse, undermines it. Because these are always hypotheticals, the correct answer doesn't need to prove the conclusion. It just has to move the needle in the supporting direction more than any other choice.
RC Strengthen is the mirror image of RC Weaken — same hypothetical framing, opposite direction. It also closely resembles LR Strengthen, with one key difference: in LR you are handed a compact, self-contained argument; in RC you first have to locate the targeted argument inside a long passage, often a sub-argument in one paragraph rather than the passage's overall thesis.
Before you can find the right strengthener, you need a mental catalog of the kinds of things that can strengthen an argument. The correct answer on any given question will usually fall into one of three families.
Affirm an assumption. Every argument rests on unstated premises. An answer that confirms one of those unstated premises closes a logical gap and makes the conclusion more secure. If an argument assumes that a drug's effects in mice carry over to humans, a study showing that analogous drugs have had the same effect in humans strengthens the argument.
Rule out an alternative explanation. Many passage arguments propose a causal or interpretive claim (X caused Y, this pattern is best explained by Z). If a rival explanation is still live, the argument is weaker. An answer that eliminates a competing explanation — by showing the alternative cause wasn't present, or that the competing theory would predict different evidence — strengthens the original claim by process of elimination.
Provide additional evidence. Sometimes the argument is built on limited data, a single case, or a single mechanism. An answer that extends the evidence base — another observation consistent with the prediction, a similar case where the same mechanism produced the same result, or direct evidence confirming how the proposed mechanism works — reinforces the conclusion by making the support broader.
Strengthen stems come in four recognizable flavors. They test the same underlying skill; the wording choice usually reflects whether the passage's targeted claim is a general position, a scientific hypothesis, or a specific causal prediction.
Variation A — "Most strengthen / most support" (25 questions, 66%). The dominant phrasing. "Which one of the following, if true, would most support [X]?" or "Which one of the following, if true, would most strengthen the author's argument?" Direct strengthen language; "support" and "strengthen" are the operative words.
Variation B — "Bolster / reinforce" (1 question, 3%). Uses stronger support language. "Which one of the following, if true, would cast doubt on passage B but bolster the argument in passage A?" A rare variant, often appearing in comparative passages where strengthening one passage's argument simultaneously weakens the other's.
Variation C — "Provide evidence for" (2 questions, 5%). Frames the task as finding evidence rather than logical support. "Which one of the following, if true, would best serve as supporting evidence for [X]?" The answer should read as a findable fact (a study result, an observation) rather than an abstract logical prop.
Variation D — Other / mixed (10 questions, 26%). Assorted phrasings: "would lend the most credence to [X]," "would most help to strengthen the author's main claim," "The author would consider the explanation more favorably if it were shown that..." All functionally equivalent to Variation A.
A four-step process works for every variation. The critical discipline is not to read the answer choices first — Strengthen choices are designed to look plausible in isolation, and the only way to separate them cleanly is to know the argument's gap before you look at them.
Step 1 — Find the target argument. The stem usually names a specific position ("the passage's position concerning the apparently healthful effects of moderate wine consumption") or a specific person ("the author's analysis of the Great Migration"). Go back to the passage and locate the exact paragraph or subsection that makes that argument. This is rarely the passage's overall main point — it is almost always a narrower claim.
Step 2 — Identify the argument's structure. What is being concluded? What evidence is being offered? Is it a causal claim, a historical interpretation, a prediction, or a comparative evaluation? The structure determines what kind of strengthener will work.
Step 3 — Predict the gap. Ask what the argument is assuming, what alternative explanations remain live, or where its evidence is thin. This is the vulnerability an ideal strengthener would patch. Form a rough idea — "an answer that rules out the alternative cause," or "an answer that confirms the mechanism."
Step 4 — Evaluate each choice for direction and degree. First ask: does it strengthen, weaken, or do nothing? Eliminate everything that isn't a strengthener. Among the remaining strengtheners, the correct answer is the one that strengthens most — the one that addresses the most critical gap or provides the most directly relevant support.
Correct answers average about 20.4 words and read as self-contained factual claims — a study result, an observed pattern, a historical fact. They are always external to the passage: if you recognize the content as something the passage already said, it is not the answer.
The correct answer fills the most critical logical gap in the targeted argument. Common patterns include confirming the proposed mechanism (showing how X produces Y), eliminating a competing explanation (ruling out an alternative cause), extending the evidence base (an additional observation consistent with the prediction), supporting a key assumption (evidence for an unstated premise), and the analogous case (a similar situation where the same mechanism produced the predicted result).
The bar is most strengthens, not proves. An answer that provides modest support in exactly the right direction beats an answer that provides strong support in a loosely adjacent direction.
Wrong answers on Strengthen questions follow predictable patterns. Seeing them as patterns makes them easier to cut.
Trap 1 — Irrelevant but topical. The answer shares vocabulary with the passage and sounds "about" the right subject, but it doesn't actually bear on the targeted claim. The passage talked about wine and health; the answer is a true fact about wine that doesn't support the specific health claim. Defense: don't reward topical overlap — ask whether the fact actually moves the argument's conclusion.
Trap 2 — Actually weakens. The answer provides evidence that cuts against the argument rather than for it. Test-takers in a hurry see the topic match and pick it without checking direction. Defense: after identifying your candidate, explicitly ask "does this make the conclusion more or less likely?"
Trap 3 — Strengthens the wrong claim. The answer strongly supports some argument in the passage, just not the one the stem asked about. This is especially common in passages with multiple embedded arguments. Defense: keep the specific target statement in view while evaluating each choice.
Trap 4 — Half-strengthener. The answer starts as a clear strengthener but includes a clause that partly undercuts the support, or it only strengthens under assumptions the passage doesn't make. Defense: read each choice all the way through, not just the opening.
Strengthen has a base difficulty of 3. It stays at 3 when the argument has a clear gap and the correct strengthener directly fills it. It escalates when LSAC manipulates two features.
Difficulty 4 — hidden or compound gap. The argument is complex, its vulnerability isn't obvious, and several answers look like they strengthen. The correct one is best only after you articulate precisely what the argument assumes. At this level the phrase "most strengthen" is doing real work — you are ranking multiple supporters.
Difficulty 5 — indirect mechanism or comparative-passage crossfire. The correct strengthener works through an indirect logical path (e.g., ruling out an alternative whose presence the passage never explicitly acknowledged), or the question is on a comparative passage where the right answer must strengthen one passage while weakening the other — a two-way test that most trap answers fail.
RC Strengthen is heavily skewed toward single passages: 34 questions (89%), vs. 4 (11%) on comparative passages. When Strengthen does appear in a comparative set, the stem often has the two-way structure (strengthen A while casting doubt on B), which is what pushes those into the difficulty-5 bucket.
Any of the following stems signal a Strengthen question. Recognize them instantly and switch into the four-step workflow: locate the target, structure the argument, predict the gap, then rank the choices by direction and degree.