Logical reasoning PrepTest 130 · Section 1 · Question 18

Incorrect. Very close! However, it's not the total number of accidents but rather the accident rate that is relevant. If the major airlines have the same number of accidents as the low-fare airlines, but they've flown 100x as many flights, then their safety record is even better than those airlines!

Incorrect. While the argument does note that the low-fare airlines have short safety records, it establishes that the major airlines have long-standing records, so it's incorrect to say that "each" record is too brief to draw a conclusion from.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Low-fare airlines: Safe but short record
Major airlines: Long records
Conclusion: Major airlines are safer than low-fare airlines

Answer Anticipation:
From the premises to the conclusion, this argument is permeated with comparisons between low-fare airlines and major airlines. In general, arguments based on comparisons will be flawed because they neglect some relevant comparison between the groups, or they fail to establish the relevant comparison that would support the conclusion.

Here, the conclusion is about safety, and the argument raises information about the safety records of the types of airlines, so it doesn't fail to establish the relevant criteria. It's therefore likely that the flaw in the argument is that it doesn't compare the two airlines over the relevant metrics. But it does bring up the safety records of the two airlines! So what gives?

This is where careful reading is necessary. While it establishes that the records of low-fare airlines show "few, if any, accidents," the argument only states that the major airlines have "long-standing records reliably indicating" their safety. Note that it doesn't say that the records indicate that the records are safe—just that the records are reliable! The argument fails to actually establish the relevant piece of information about major airlines in order to allow the comparison in the conclusion to be drawn.

Answer Explanation:
This answer highlights the missing piece of information to complete the comparison between the low-fare and major airlines. Low-fare airlines are noted as having records showing few, if any, accidents, but the major airlines are only stated to have long-standing records. Without knowing what those long-standing records show—mainly, are these airlines safe?—the argument can't reach its conclusion.

Key Takeaway:
Arguments that are based around comparisons generally will fail to establish relevant criteria, or will fail to compare the elements over all relevant metrics. Correct answers tend to establish these criteria, or raise a relevant point of comparison unmentioned in the stimulus.

Additionally, many of these arguments will raise information about one of the elements in the comparison and then go silent on the comparable information on the other element. When that happens, the correct answer almost always raises that piece of information about the second element. These can be harder to spot because, as noted in the first takeaway, many correct answers raise comparisons themselves, so an answer that only addresses one element can seem to be missing a key part. But in bringing up a piece of information that was established in the stimulus, this type of answer can allow a comparison to be drawn while only mentioning one element. In short—if a piece of information is established about one element in a comparison but the comparable information isn't mentioned about the other, the correct answer will often bring up that information for the second element in the comparison.

Incorrect. The argument relies on records being complete, but it doesn't rely on safe airlines having more complete records. In fact, in using the records to justify a conclusion about safety, the argument is implicitly assuming that these records are fairly comprehensive and complete.

Incorrect. The argument allows for there to be some accidents here and again as long as the overall safety record still shows a high level of safety.