Inference Questions

On an inference question, you’re given a paragraph with a bunch of information, and asked which one of the answer choices can be inferred from the information in the paragraph.

In other words, you’re essentially asked “if all of the above is true, then which one of the following must be true?”

Inference questions are generally the only questions where the paragraph isn’t necessarily an argument per se. An argument has a conclusion based on supporting evidence. Inference questions usually just give you information without arguing any conclusions.

In a sense, you’re the one who is completing the argument by providing a conclusion that can be inferred using the paragraph as supporting evidence.

Your goal as you’re reading the paragraph is simply to understand and digest the information. There could be multiple possible inferences to be made from it, so it can be hard to predict the answer on these questions. But as long as you have a handle on the info, you should hopefully be able to spot the inference in the answer choices.

For example, let’s say I gave you this question:

A written survey about favorite colors was completed by all of Mrs. Polson’s 1st grade class. Two of the six students in the class were Tyler and Stephanie, who both selected red as their favorite color.

Which one of the following can most properly be inferred from the information above?

Here are some possible answer choices that would all have to be right:

At least one third of the students in Mrs. Polson’s class consider red to be their favorite color.

Not all of the students in Mrs. Polson’s class consider green to be their favorite color.

All of the students in Mrs. Polson’s class have some ability to write.

…and so on.

Even though you may not have predicted the exact right answer – since as you can see it could have been any of several things – as long as you properly digested the info in the paragraph, then as you’re reading any one of the above three statements you would hopefully be thinking “yeah, I guess this does have to be true”.

The first one is the most basic one, since two is one third of six (it’s “at least one third” since I don’t know what the other four selected – maybe they all picked red!). And, if they completed a written survey, then they certainly must have some ability to write.

Also, even though I never mentioned the color green in the paragraph, since at least a couple of the students consider red to be their favorite color, it’s implicitly true that not everyone in the class considers green to be their favorite color. I could have replaced “green” with any color that’s not red, and the statement would still have been a valid inference, even though red was the only color mentioned in the paragraph. This is just to illustrate how important it is not to be alarmed by new words or ideas in an answer choice and cross it out right away – use your lawyer mind and think about it analytically first!

Now, even though it’s not always possible to predict the answer on inference questions due to the multiple possible inferences from any one paragraph, there are often strong hints towards what the inference will be. The strongest and most reliable hint you’ll see in an inference question is a causal chain.

A causal chain is a chain of either sufficient or necessary conditions (for a refresher on these, see this guide).

For example, a sufficiency chain would be:

A causes B, B causes C, and C causes D.

A necessity chain would be:

A is required for B, B is required for C, and C is required for D.

Whenever there is a causal chain in the paragraph of an inference question, the answer will be connecting distant items on the chain at least 99% of the time (I’d say 100% but I’m worried someone will find one instance to prove me wrong).

When I say “connecting distant items on the chain”, here’s what I mean: on the sufficiency chain above, if A → B → C → D, you can infer that A → D. (You can also infer that A → C and B → D.)

For example, if setting my alarm ensures I will get up early, and getting up early guarantees I will go biking in the morning, and going biking in the morning ensures I’ll have a productive day – it can be inferred from this that setting my alarm ensures I’ll have a productive day. (It can also be inferred that getting up early ensures I’ll have a productive day, and that setting my alarm ensures I’ll go biking in the morning.)

A necessity chain might be: reading regularly is necessary for expanding your mind, expanding your mind is necessary for being personally fulfilled, and being personally fulfilled is required in order to be a good parent. Therefore, by this logic, reading regularly is a necessary condition for being a good parent.

Always watch for these causal chains in inference questions paragraphs as they will consistently lead you to the answer. It’s one of the most foolproof LSAT tricks I know of.

Here’s an actual example from June 2007:

A five-point causal chain about local politics – wahoo! The two things in sentence 1 are factors that cause the isolation mentioned in sentence 2, which in turn causes the effect mentioned at the beginning of sentence 3 (less chance that any act will elicit a positive response), which in turn discourages participation in local politics.

Rare coverage


                                                    isolation ⇨ less chance of positive response ⇨ participation discouraged


Secretive business

Therefore, the inference will connect distant items on this chain. In other words, the answer could be that rare coverage in the media about local politics causes discouraged participation from residents in local politics. Or, in other words:

Rare coverage → participation discouraged

If you look through the answer choices you’ll see that this essentially actually is the answer. Another way of saying that rare coverage causes discouraged participation is that less rare coverage would reduce a source of discouraged participation. Bingo – the answer is (D).

It could have also said that “conducting local political business less secretively would reduce at least once source of discouragement from resident participation in local politics”, and that would have had to be the right answer as well. The paragraph tells us that these are both factors of discouragement.

The point is that we were able to see that the answer would be connecting two items on the causal chain illustrated by the paragraph.

Beware of (B) though – that’s not exactly what this answer choice does! Always be careful with the word “should”. All we know for sure here is that X causes Y. We have no idea whether that’s a good thing or a bad thing – maybe it should happen or maybe it shouldn’t. For all we know, maybe discouraged resident participation in local politics is a good thing!

(A) is tricky as well – we don’t know that it would be likely, we just know that it would be more likely. In other words, yes, less isolation would certainly make it more likely for acts to elicit a positive response, but we still don’t know that it would be likely – it might make the odds go up from 2% to 3%.

(C) adds in unsupported information (we don’t know that it’s the most important factor, we just know that it’s a factor) and (E) follows the chain backwards (from participation to isolation instead of from isolation to participation).

As you can see, the wrong answers can be very tricky. Always beware not to pick an answer that goes too far and infers something that simply wasn’t evident from the paragraph. (C) is a common error in these questions – just because something causes something, doesn’t mean it’s the biggest cause; just because something is an effective way of doing something, doesn’t mean it’s the most effective way; just because something is dangerous, doesn’t mean it’s the most dangerous, and so on.

In summary:

    • Read the paragraph, digest the information, and then look for something that must be true
    • If you spot a causal chain in the paragraph, be prepared for the answer to connect two things on the chain
  • Beware of answer choices that are too extreme and not necessarily proven by the paragraph

For full clarity on very tough logical reasoning questions, check out my comprehensive LSAT course.

Oh, and if you haven’t already, download your Free MasterLSAT Study Guide, which will tell you exactly what you need to do to reach a 99th-percentile score on the LSAT.

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