LSAT 124 | Section 2 | Logical Reasoning: Q17

LR Question 17 Explanation

QUESTION TEXT: Reporter: A team of scientists has recently devised a new test…

QUESTION TYPE: Necessary Assumption

CONCLUSION: Autistic children can benefit from treatment earlier in life.

REASONING: A new test exists, which for the first time can accurately diagnose autism in children as young as 18 months old.

ANALYSIS: The argument is trying to move from the accuracy of a diagnostic test to a conclusion about treatment. But it skips over a key step: just because a test correctly identifies most autistic children doesn’t mean it’s reliable enough to base treatment decisions on. The test gave some false positives, and the argument doesn’t address what that means for those children. To solve this, look for an assumption that connects the test results to the idea that it’s appropriate or beneficial to begin treatment based on those results. Without that, the conclusion doesn’t hold.

___________

1. No accurate test would have been a necessary assumption, but it’s quite possible (inaccurate) tests existed.
2. CORRECT. Yes. If this weren’t true, the conclusion is worthless, because the test does give false positives.
3. Not necessary, the test only claims to diagnose children 18 months old.
4. This may sound cruel, but the conclusion wasn’t concerned with the non-autistic, falsely identified children. They could be scarred for life and the conclusion about autistic children could still be correct.
5. There could have been reliable evidence, yet still no accurate means of diagnosis.

Recap: The question begins with “Reporter: A team of scientists has recently devised a new test”. It is a Necessary Assumption question. Learn how to master LSAT Necessary questions on the LSAT Logical Reasoning question types page.