An inference is a conclusion

Let’s start with a quick refresh on LSAT strategy: On Logical Reasoning, the procedural part starts with checking the prompt before reading the passage. It looks like this:

1. Check the prompt for how the right answer will relate to the argument. You know the answer will generally either describe the support and/or conclusion in the passage, or it will be support or a conclusion that fits into the passage.
2. Read the passage and tag each statement as either conclusion, support, or background. You know conclusions get support from other statements, and background doesn’t give or get support. It’s just there for context or clarity.
3. Carefully map the wording of the answer choices to the wording of the passage. You know everything stated in every right answer will align to statements made in the passage, so anything that doesn’t can be confidently eliminated.

Got it? Let’s do this!

*PrepTest 140 is available for FREE on LawHub even if you don’t have a subscription or access through another prep app.

PROMPT: How will the right answer relate to the argument?

“The argument proceeds by” can be a pretty confusing prompt the first time new test-takers see it. But it’s just a weird way of telling you the right answer will accurately describe the argument.

A quick peak at the list of answer choices shows us they all start with “Inferring…” That’s a key piece of the puzzle here, since they expect you to know what gets inferred is a conclusion. And for extra credit, what we infer from is support for the conclusion. So we’ll make sure the inference described in the answer aligns to the author’s conclusion in the passage, and that the rest aligns to the support. Now we can read the passage and tag which statements are which.

PASSAGE: Tag the conclusion/s and support

[BACKGROUND]: The first sentence up to the colon is just introducing the key piece of support.

[SUPPORT]: “The more successful the crops, the higher the birth weights.” You want to recognize this is a very common flavor of support/evidence. Do you know what we call it when two things go together or correspond like the crops and birth weights in this passage? You got it, it’s a correlation.

If you didn’t spot that this time no worries. By test day you want to catch it every time a passage cites a correlation, which will typically be used as support.

[CONCLUSION]: “The health of a newborn depends to a large extent on the amount of food available…”

The conclusion is signaled by “This indicates that…”. And here again we see a very common pattern. You want to recognize that “depends” is being used to say that the amount of food available causes better or worse health for newborns.

By test day, you really gotta recognize every time a passage cites cause-and-effect. It happens multiple times in every LR section, and pretty much every time the right answer will talk about the same cause-and-effect relationship the passage does.

ANSWERS: Carefully map the wording of the answers to the passage

(A) inferring from a claimed correlation between two phenomena that two other phenomena are causally connected to one another.

Boom! This pretty much exactly matches the tags we applied to the passage above. You may only need to double check that “two other phenomena” makes sense. And it does! The correlation is between birth weights and the success of crops, but the conclusion is about newborn health and the availability of food. Those are close, but not the same.

(B) inferring from the claim that two phenomena have fluctuated together that…must be the sole cause…

This gets close, but be careful. Fluctuated means a number went up AND down. The passage only says “The more…, the higher…” It doesn’t actually say anything fluctuated. The word “sole” is maybe more obviously problematic, since the conclusion definitely does NOT say it’s the only cause.

(C) inferring from records concerning a past correlation…that that correlation still exists.

I like the first part since the first sentence of the passage mentions the past. But the conclusion isn’t about “that correlation”. Also there’s nothing in the conclusion that sounds like “still exists”. It may not seem critical but that wording has to map to similar wording in the passage, otherwise this can’t be the right answer.

(D) …existence of a common cause…and then presenting a hypothesis about that common cause.

A common cause would mean something has multiple effects, but that doesn’t align with the passage. It’s just one thing causing one other thing.

(E) inferring the existence of one causal connection from that of another…

Love the first part. Remember “Inferring” always wants to line up to the conclusion, which did make a causal connection. But there was only one causal connection, so “another” doesn’t map to anything stated in the passage.

(A) is the correct answer.

The big takeaway: An inference is always a conclusion.

I hope this mapping thing is starting to feel comfortable. We also got a peek at how powerful pattern recognition (a/k/a the fun part of LSAT strategy) can be, but you can’t have all the fun without also ruthlessly sticking to the procedural part. And that means applying careful mapping on every question.

Common patterns in this question:

• There are a few flavors of prompts whose answers describe the passage. These “proceeds by” prompts are slightly less common than the ones that ask for “the role played by” a given statement in the passage. The most common are the ones that ask for the “flaw” in the argument or why it’s “vulnerable to criticism”, which you should expect to see three to five times in every section.
• Cause-and-effect, specifically the bad assumptions that correlation = causation and that a cause is the only cause. Every LR section will have multiple passages that use cause-and-effect. Cause-and-effect is phrased a LOT of different ways (e.g. X leads to Y, X produces Y, Y was set off by X, etc…). You may need a little time for it to become really familiar, but start training yourself now to catch it every time.

How’d that go? This a 4-star question, the highest difficulty level according to LSAC. So give yourself a pat on the back if you got it, and shake it off if you didn’t. Most of you don’t actually need to get this one right to reach your target score.

The plan will work if you do.