In a year-long study, one group of students learning a foreign languag

Question

In a year-long study, one group of students learning a foreign language was taught using an immersive method (only the target language was used in class), whereas an otherwise similar group of the same size was taught using a traditional method (mix of native and target languages). Both groups were assessed for fluency only at the end of the academic year. Seventy-five percent of the immersive group achieved fluency in speaking and writing, but only sixty percent of the traditional group achieved fluency when assessed at the end of the year. The researchers concluded that the immersive method must have activated natural language acquisition abilities in some students in the immersive group.

In order to evaluate the strength of the researchers' reasoning, it would be most helpful to know which of the following?

(A) Whether there were statistically significant personality differences between the students who achieved fluency and those who did not 
(B) The proportion of participants who had previously attempted to learn this foreign language before joining the study 
(C) How long it takes on average for students to achieve fluency in the target language 
(D) Whether students were informed about which specific language they would be learning prior to the study 
(E) The margin of error in the fluency assessment tool used to evaluate the students at the end of the year

MrinmoyNegel · Answer

Can someone explain why the answer isn't B?

Brian_1 · Answer

In my view, its a attempting to distort your reasoning. While logically yes, a person who attempts to learn a language might learn it quickly later on in a separate instance, it might not be the case too !

Attempting to learn and actually attaining fluency are disparate. If the answer is B, you are assuming that all folks who are attempting to learn a language, find it easier to learn it later on - which is a bit disingenuous imo.

cburchfield · Answer

I'm not sure I understand why the margin of error in the testing tool is important over the general makeup of the two classes. The scores were vastly different, and therefore the margin of error shouldn't be taken into account.

Carlosgmdn · Answer

Hi everyone, I’m new to the forum, but I hope I can be helpful!

Here’s how I approached this question:

The main conclusion of the argument is:
 
The researchers concluded that the immersive method must have activated natural language acquisition abilities in some students in the immersive group.
 
The question asks:

In order to evaluate the strength of the researchers' reasoning, it would be most helpful to know which of the following?

Although several factors could influence how effective one method is compared to another — for example, some students may have already been proficient in the language (B), may have known which language they were going to study in advance (D), or may have had certain personality traits (A) — the question specifically asks what would help us evaluate the strength of the reasoning behind the researchers’ conclusion.

To assess reasoning strength, we need to consider whether  there’s any flaw in the evidence or logic used to support the conclusion . That’s why option E is the most relevant:  if the assessment tool used to measure fluency had a large margin of error, then the observed difference between the two groups (75% vs. 60%) might not be meaningful. This would directly weaken the researchers’ reasoning.

As for option C, I believe it’s out of scope because the average time it takes to achieve fluency doesn’t impact whether this specific comparison supports the researchers’ conclusion.

surya.nair · Answer

If the 75% in immersive group and 60% in the other group have a particular personality trait, then it means that it's the personality that helped the learning process.
Won't that make A the right answer?

egmat · Answer

surya.nair  You're absolutely right that personality could influence language learning success. However, choice (A) asks about personality differences between  successful and unsuccessful students  - this means comparing the 75% who succeeded to the 25% who didn't within the immersive group, and the 60% who succeeded to the 40% who didn't within the traditional group.

Why This Doesn't Help Evaluate the Argument:

The researchers' conclusion is about the  difference between groups  (75% vs 60% success rates). For personality to explain this difference, we'd need to know that the  immersive group had more students with success-promoting personalities than the traditional group . But choice (A) only tells us about personality patterns  within  each group, not  between  groups.

Think of it this way: Even if outgoing students do better in both groups, that doesn't explain why the immersive group had a 15% higher success rate - unless the immersive group happened to have more outgoing students to begin with (which (A) doesn't tell us).

Why (B) is Correct:

Choice (B) asks about prior language learning attempts - this  could vary between groups . If the immersive group had more students with prior experience, that would provide an alternative explanation for their higher success rate, weakening the researchers' conclusion that it was the method itself.

I am sharing with you a framework for Evaluation questions:

When GMAT asks what would help evaluate an argument, look for information that:
 
 Provides alternative explanations for the observed difference 
 Tests whether groups were comparable at the start 
 Addresses confounding variables between groups (not within groups)

Remember:  Within-group patterns ≠ Between-group explanations

arushi118 · Answer

But I think that even if the assessment tool had a large margin of error, that error should be the same for both methods - So how will this help us evaluate?

In a year-long study, one group of students learning a foreign languag

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In a year-long study, one group of students learning a foreign languag

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