Logical Reasoning

PT155 · S1 · Q17 For several years the Technology Institute

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

For several years the Technology Institute has used a new experimental curriculum in its plumbing program.

Conclusion (this shows that)

The new curriculum has lowered the quality of plumbing instruction.

Evidence

A survey last year found that only 1/3 of the graduates were able to pass the plumber's certification test (which is well below the national average).

Evaluate

We can't really judge the author's Comparative conclusion, which claims that the plumbing instruction is now worse quality than it was before, thanks to the new curriculum.

In order to compare whether the quality has changed / lowered, we would need some data point from before / after.

This argument only provides the "after" data point. With the new curriculum in place, only 33% of graduates pass the certification test. What was that percentage "before" the new curriculum was installed?

If we the grads from this program used to have a 25% passing rate and now have a 33% passing rate, then we'd think the new curriculum is improving the quality.

The argument tries to compare the 33% rate of Tech Institute's grads to the national average, but that has nothing to with assessing whether T.I. currently is better than T.I. was with the old curriculum.

Finally, we have a language shift from "what % of grads pass this test" to "what the quality of plumbing instruction" is. Do we really know that this certification test is a good metric of the quality of plumbing instruction? Maybe it's a stupid test, and quality of plumbing instruction should be judged more by how well these plumbers perform out on the job.

Goal

Look for an answer complaining about our Incomplete Comparison: is a 33% pass rate better / worse than the pass rate we had with the old curriculum?

Or look for an answer talking about the dubious idea that this certification test stands as an adequate measurement of what quality of instruction T.I. provides.

17.

The reasoning in the argument is most vulnerable to criticism on the grounds that the argument

  1. treats a phenomenon as an

    Not Causal

    This answer refers to the famous Causal flaw, in which an author overconfidently concludes one possible causal explanation where others might exist (specifically, this answer is saying, "You're assuming that Y is an effect of X when it really might be that Y causes X, i.e. Reverse Causality"). We didn't have any correlation here that could be vulnerable to alternate explanations of Reverse Causality. We know the chronological sequence. The new curriculum has been used. Later, once people graduated from that course, their pass rate was 33%. The author does think that the new curriculum caused that 33% pass rate, but we would sound crazy trying to argue, "Hey, author --- did you ever consider that maybe that 33% pass rate caused the new curriculum?" because we know that the 33% didn't happen until after the new curriculum was already built and taught.

    25% picked this

  2. uses a lack of evidence

    Trap

    Not Unproven vs. Proven False Bad Evidence Match This refers to another of the ten famous flaws, Unproven vs. Proven False, in which an author explains how someone failed to prove X (either through faulty reasoning or through lack of evidence) and then concludes illicitly that X must be false. This argument doesn't have that sort of evidence. The conclusion does indeed conclude that quality has decreased, but the evidence wasn't the author saying, "No one's been able to prove that quality has increased!" The evidence was, "The pass rate sucks. It's well below the national average."

    8% picked this

  3. Correct

    concludes that something has diminished

    Why this is right

    If a Flaw answer describes a 2-part reasoning move, like confuses X with Y mistakes Y for X concludes Y on the grounds that X infers, from the claim that X, that Y then we want to ask ourselves whether the Evidence part and the Conclusion part match up with their respective targets. Did this argument conclude that "something has diminished in quality"? Sure, the conclusion is saying that quality of plumbing instruction has diminished in quality. Did the evidence establish that the quality of plumbing instruction is "of below-average quality"? Yes, basically. It established that certification test scores are of below average quality (they are well below the national average). To accept this answer, we have to sort of accept the idea that ability to pass this test is some indication of quality of instruction. That might make us hold off on picking this on the first pass, but it's a pretty common sense assumption to think that a plumbing program's main goal with its instruction is to get you certified as a plumber. So the less it succeeds in getting students certified, the lower quality it was.

    Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

    57% picked this

  4. uses a national average as

    Never a Flaw (specify number)

    There are hundreds of trap answers written in this style, in which the complaint is that we didn't name names, we didn't provide exact definitions / numbers / measurements. These questions aren't hinging on specific facts, just the logical force of ideas. Being "below-average" has some logical force, regardless of what specific number that average is.

    2% picked this

  5. confuses a factor’s presence being

    Trap

    Not Necessary vs. Sufficient Out of Scope: required to produce phenom This refers to the #1 famous flaw, Necessary vs. Sufficient, in which the author presents a conditional logic rule and then makes an argument that interprets that rule in an illegal backwards or negated fashion. We can start by asking ourselves, "Was there a conditional logic rule in the premise?" There was not, here, so this answer has no chance. Nothing in the argument talks about something being required to produce a phenomenon.

    9% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free