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LSAT weaken questions ask which new fact would make the conclusion less likely, not false. Recognize them from if true, most weakens or most calls into question. Solve them by attacking the link between evidence and conclusion, never by disputing whether a premise is accurate.
Recognition is the cheapest point on the section. Every weaken question announces itself in the stem, and the stems recycle a small number of formulations. Learn them and you stop spending seconds deciding what you are being asked.
Stem wordingWhat it tells youWhich one of the following, if true, most weakens the argument?The standard stem.Which one of the following, if true, most seriously calls into question the conclusion above?Calls into question, same task.Which one of the following, if true, would most undermine the reasoning above?Undermine the reasoning, so aim at the inference.Which one of the following, if true, casts the most doubt on the explanation offered?Common on causal arguments; the target is the proposed cause.
Read the stem before the stimulus. Knowing you are hunting vulnerable link changes what you notice on the first read, and reading the stimulus cold means reading it twice.
Three steps, in this order. The order is the method, because the most common way to lose this question type is to read the answer choices before you have decided what you are looking for.
StepWhat it means in practiceIdentify what kind of argument you are attackingCausal claims, sample-based generalizations, and plans-to-achieve-a-goal each have a signature weakness. Causal claims fall to alternative causes and reversed causation. Generalizations fall to unrepresentative samples. Plans fall to a side effect that defeats the goal.Attack the gap, not the factsPremises are given as true on this test. A choice that says the study was poorly conducted is usually a wrong answer dressed as a strong one. The right answer accepts the evidence and shows it does not carry the conclusion.Ask what the argument had to assume, then break itEvery weaken answer is the negation of something the argument quietly needed. If you can state the assumption, you can usually predict the attack before reading a choice.
The stimulus and answer choices below were written for this page. They are not taken, adapted or paraphrased from any real LSAT question, because reproducing licensed test content is not something we do. The style is the target; the content is ours.
Stimulus.
Employees at Halvorsen Logistics who chose to attend the company's optional resilience workshop recorded 30 percent fewer stress-related absences over the following year than employees who did not attend. The workshop is therefore an effective way to reduce stress-related absence.
Question. Which one of the following, if true, most weakens the argument?
(A) Employees who chose to attend the workshop had recorded substantially fewer stress-related absences in the year before it was offered as well
(B) A small number of employees who attended the workshop recorded more absences in the following year than in the preceding one
(C) The workshop cost considerably more per employee than Halvorsen had budgeted
(D) Some employees who did not attend the workshop used other stress-reduction resources offered by the company
(E) Stress-related absence rose across the logistics industry as a whole during the year in question
The answer is (A).
The argument compares two groups that sorted themselves. Choice A shows the gap between them predates the workshop, which means the workshop is not what explains it. That is self-selection, the standard failure of any voluntary-program study, and it leaves the evidence intact while removing its power to support the conclusion.
Reviewing the four wrong answers is worth more than confirming the right one. Each was engineered to catch a specific misreading, and naming that misreading is what stops it recurring.
ChoiceWhy it failsBA few individual exceptions are compatible with a real average effect. Weakening requires something that bears on the group comparison.CCost speaks to whether the workshop is worth running, not to whether it works. Effectiveness and value are different conclusions.DIf anything this strengthens the argument, since it means the comparison group was not simply going untreated and the gap survived anyway.EAlso strengthens. A workshop group that improved while the industry worsened looks more effective, not less.
Across weaken questions, the wrong answers fall into recurring shapes. Once you can name the shape you can eliminate on sight instead of arguing with each choice on its merits.
TrapHow it worksThe premise attackDisputes the accuracy of the data. On this test premises are true, so this is out of bounds.The irrelevant cost or feasibility answerArgues the plan is expensive or inconvenient when the conclusion was about whether it works.The backwards choiceStrengthens while sounding negative. Check direction before you check force.The single counterexampleOne exception rarely dents a claim about a group average, however vivid it sounds.
One question people always ask about weaken questions is how many appear per test. There is no honest answer to give. LSAC does not publish how many questions of each type appear on a given test, and no honest page can give you a percentage without inventing it.
What is published is the scored structure: the LSAT is two scored Logical Reasoning sections and one scored Reading Comprehension section, four 35-minute sections in total including one unscored variable section, with a 10-minute intermission after section two, per LSAC's own test specifications (https://www.lsac.org/lsat/register-lsat/accommodations/specifications-lsat-and-lsat-argumentative-writing). Two of the three scored sections are Logical Reasoning, so LR carries roughly two thirds of your scored questions.
That ratio is worth planning around. A per-type count is not, because nobody outside LSAC has one.
That matters practically, because study plans built on invented percentages allocate your weeks wrong. If you read that weaken questions are eleven percent of the test, ask where the number came from. It came from somebody counting a handful of released tests and rounding, which is not the same thing as a published specification.
Plan on the structure instead. Two of your three scored sections are Logical Reasoning, weaken questions appear in both, and no single LR type is rare enough to skip or common enough to carry your score by itself.
Drilling weaken questions in a block is efficient for learning the pattern and misleading about whether you have learned it. Blocked practice lets you know the question type before you read the stimulus, which is exactly the cue the real test removes.
The size of that gap is measured. In a classroom study of 787 students across 54 classrooms, interleaved practice produced 61 percent correct against 38 percent for blocked practice at a 33-day delay, an effect of d = 0.83, per Rohrer, Dedrick and Hartwig (2019), Journal of Educational Psychology (https://gwern.net/doc/psychology/spaced-repetition/2019-rohrer.pdf). Blocked practice felt better and tested worse.
The same reversal shows up in how students judge their own learning. Kornell and Bjork (2008), Psychological Science (https://gwern.net/doc/psychology/spaced-repetition/2008-kornell.pdf) found 78 percent of students judged massed study as good as or better than spaced study while 78 percent actually performed better spaced. Your sense that a drill block is working is not evidence that it is.
So use blocks to build the recognition, then stop. Once you can name a weaken question from the stem without thinking, the questions belong back in mixed sets where you have to identify the type yourself, because identifying it is half the skill.
Review is where the points are, and review is not reading the explanation for the answer you missed. The intervention research is blunt about this: across 28 studies and more than 16,000 participants, test prep as a category produced an overall effect of g = .26, and practice tests on their own produced g = .19 at p = .233, which is not statistically significant, per Hao and colleagues (2025), Review of Educational Research (https://journals.sagepub.com/doi/10.3102/00346543251360775). Taking questions is not the active ingredient.
What did work in that same Hao and colleagues analysis was structured practice on the reasoning: workbooks at g = .40 and explicitly teaching test-taking skills at g = .35. And there was no dose response at all, with neither contact hours at p = .489 nor program length in weeks at p = .314 predicting outcomes.
More hours is not the lever. Better review is.
Concretely, for every weaken question you get wrong, write three lines before you look at any explanation: what you thought the vulnerable link was, what it actually was, and the exact word in the stimulus that would have told you. The third line is the one that transfers.
Then leave the question alone for at least a day before you revisit it. Testing yourself beats restudying at g = 0.50 across 61 studies, the advantage rises to g = 0.69 when the delay is a day or more against g = 0.41 under a day, and feedback roughly doubles the effect at g = 0.73 with against g = 0.39 without, per Rowland (2014), Psychological Bulletin (https://pubmed.ncbi.nlm.nih.gov/25150680/).
Every LSAC figure on this page was taken from LSAC's own pages and last checked on July 26, 2026. Prices, dates and policies move without notice, so the source link sits next to each number rather than in a bibliography at the bottom.
Where LSAC has not published something, this page says so in those words rather than filling the hole with a plausible number. That is the difference between a gap and a guess, and only one of them is safe to plan around.
If true paired with weakens, undermines, calls into question, or casts doubt. The if true instruction is what separates these from flaw questions.
Classify the argument as causal, sample-based, or plan-based, name the assumption that type depends on, and pick the choice that breaks it while accepting the premises.
LSAC does not publish per-type counts. The published structure is two scored Logical Reasoning sections out of three, per LSAC's test specifications, and weaken questions appear across both.
The stem says if true, so you treat the choice as fact. Within the choice, though, hedged language like may weakens its force, and a definite statement usually beats a tentative one.
An alternative explanation for the correlation, with reverse causation and self-selection close behind. Recognizing which one is on offer is most of the work.
Written by Ali, Georgetown Law, founder of Lovare Institut.
August 5, 2026
August 5, 2026