LSAT Weaken Practice Question: Measurement Change
An original weaken question from our free Question of the Day rotation, built around a trap the LSAT reuses constantly: measurement change. Try it first, then read the explanation — it teaches the move, not just the answer.
Your job:Make the conclusion less believable.
Last autumn, Hollis Orchards began shipping its apples in a newly designed padded crate. This year, the percentage of its apples rejected by grocery buyers for bruising fell from nine percent to four percent. The orchard's operations manager concluded that the new crates protect apples in transit better than the old crates did.
Which one of the following, if true, most weakens the manager's argument?
Show the answer & full explanation
The correct answer is E
The JBDM line
Just because the rejection rate fell after the new crates arrived doesn't mean the crates caused the drop.
The maybes
- MaybeMaybe the buyers changed how strictly they grade.
- MaybeMaybe this year's apples were firmer or the harvest gentler.
- MaybeMaybe shipping routes got shorter or smoother.
Why E is right
If the biggest buyers loosened their bruising standard, rejections would fall even if the apples arrived exactly as bruised as before. The improvement may live entirely in the measuring stick, not the crates — a direct alternative explanation for the drop.
Why the others are wrong
- ACost speaks to whether the crates are worth it, not whether they work.
- BThe unchanged travel distance is neutral background.
- CCareful — a neighbor with old crates and no improvement is a control group that helps the manager's case.
- DPicking bruises existed under both crate designs, so it can't explain the change.
Sammy's note
When a rate improves, ask whether the thing being measured changed — or the measuring stick did.
What's a JBDM line?
Just Because Doesn't Mean (JBDM) is the Burton Method's foundational framework for attacking LSAT arguments: identify the premise, identify the conclusion, then say "just because [premise] doesn't mean [conclusion]" and generate "maybes" — alternative explanations that expose the gap between them. That gap is what weaken, flaw, strengthen, and assumption questions all test, so every explanation on this page starts with the JBDM line. It's a micro-lesson in the system, not just an answer key.
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