Strengthen questions hand you a wobbly argument and five new facts, and ask which fact makes the conclusion most worth believing. The word "most" matters: the right answer doesn't have to prove the conclusion, it just has to help it more than the other four choices do.
The center of gravity here is causal reasoning. A large share of strengthen stimuli conclude that one thing causes another from evidence that the two merely occur together. The classic strengtheners are predictable: rule out an alternative cause, show the effect absent when the cause is absent, show the effect present when the cause is present, or rule out reverse causation.
Because the task is "help the argument," your job starts the same way every gap-family question does, find the conclusion, find the evidence, and name what's missing. The right answer almost always speaks directly to that missing piece.
Stem language that signals this type:
"If true" means plausibility is off the table, never reject an answer because it seems unlikely in real life. The only question is: granted this fact, does the conclusion get more credible?
For causal conclusions, ask what else could explain the evidence. For predictions, ask what could intervene. For generalizations, ask whether the sample is fair. The strengthener you want addresses that specific vulnerability.
On causal arguments, the strongest help usually comes from killing an alternative explanation, "the two groups were identical in every other respect" is worth more than another data point of correlation.
Strengthen answers sit on a spectrum. An answer can help slightly and still lose to one that helps a lot. Don't stop at the first choice that helps; find the one that helps most.
An original question written in the LSAT style, not from a real test.
Ecologist: Meadows where we introduced native wildflower strips last spring had thirty percent more pollinator visits this summer than meadows without strips. Clearly, the wildflower strips caused the increase in pollinator activity.
Which one of the following, if true, most strengthens the ecologist's argument?
Pick an answer to check your reasoning.
An answer that restates the conclusion in new words adds zero support, the argument doesn't get stronger by asserting itself twice.
Some answers genuinely support something, a premise, a side remark, the general topic, but not the conclusion. Keep the exact conclusion in front of you.
Choices that introduce differences the argument doesn't turn on ("the study participants were older") feel substantive but move nothing.
Take the free diagnostic to see exactly where your points are going, or talk it through with a 170+ tutor, free, for 15 minutes.
No. It only has to provide more support than the other four choices. Answers that make the conclusion somewhat more likely can be correct if nothing else helps more.
Causal conclusions have a built-in, testable gap, correlation doesn't establish causation, so the test can write predictable right answers: rule out alternative causes, rule out reverse causation, or show the cause-and-effect pattern holding and failing together.
You must treat every answer choice as fact, however implausible. Eliminations based on "that probably wouldn't happen" are the fastest way to miss these questions.
They're mirror images built on the same gap analysis. Most students drill them together: find the vulnerability, then either patch it (strengthen) or pull it open (weaken).
Pick the new fact that damages the argument most.
Find the unstated premise the argument can't live without.
Bridge general rules and specific cases, in both directions.
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Last updated July 9, 2026 · by the theLSATguru team