LSAT 155 | Section 1 | Logical Reasoning: Q10

LR Question 10 Explanation

QUESTION TEXT: Dentist: Five recently conducted studies all show that…

QUESTION TYPE: Strengthen

CONCLUSION: Fluoridation of water does not have a substantial tendency to prevent tooth decay.

REASONING: In Europe, water is not fluoridated and there is a lower proportion of children with decayed, missing, or filled teeth.

ANALYSIS: The dentist is arguing causation based on correlation, which is normally a no-go. There are too many alternate explanations for the difference, so we need to show more that supports the conclusion than just the correlation. The correct answer will likely provide evidence that fluoride does not have the tendency to prevent tooth decay, or eliminate an explanation for the difference.

___________

1. This does not provide evidence that fluoride doesn’t prevent tooth decay. It is providing an explanation for how people in Europe might be accessing fluoride, which doesn’t help the argument.
2. This doesn’t help the argument. It re-emphasizes that the US has lots of fluoride, but doesn’t show that fluoride does not prevent tooth decay.
3. This does not strengthen the argument. The schools may teach hygiene differently, and being taught hygiene doesn’t mean that the children practice it! This doesn’t really eliminate an explanation for the difference.
4. This provides an alternate explanation for the difference, which weakens the dentist’s argument that fluoride is not helping. It’s possible that fluoride is helping, but the difference in checkup frequency puts American children behind anyway.
5. CORRECT. This eliminates a potential explanation for the difference, making it more likely that fluoride is not helping American children’s teeth.

Recap: The question begins with “Dentist: Five recently conducted studies all show that”. It is a Strengthen question. Learn more about LSAT Strengthen questions in our guide to LSAT Logical Reasoning question types.