r/LSAT • u/Great_Lawyer_4792 • 1d ago
How to solve every NA question
A lot of my students note that this helps them when they’re going through our website. Necessary assumption is not what proves the conclusion. That is a sufficient assumption, a different question type. A necessary assumption is the minimum the argument needs to survive. If it is false, the argument is dead, even if everything else in the stimulus is true.
Here is the process I teach.
1. Split the argument, then stare at the conclusion Find the evidence and the conclusion. Then look for the thing that pops up in the conclusion that was never in the evidence. Necessary assumption questions almost always do this. The conclusion introduces something new: a new term, a new claim, a new scope. That new thing is where the assumption lives, because the argument never connected it to anything.
2.Predict the minimum bridge.
The correct answer connects the evidence to that new thing in the conclusion, and does it with the least possible claim. Before reading the choices, say the bridge out loud in plain words. Not what would settle the argument. The least it needs.
3. Check the strength of every answer.
Necessary answers are quiet. If a choice says more than the bridge needs, with words like all, only, always, or most, it is selling you a sufficient assumption in the wrong question. Cross it out.
Example (not a real question)
"A study found that employees who took a short walk after lunch reported higher afternoon productivity than those who did not. So our company should encourage employees to walk after lunch if we want to raise productivity."
Which one is a necessary assumption?
A) All employees who walk after lunch will become more productive.
B) The employees' reports of their own productivity in the study were accurate.
C) Walking after lunch is the most effective way to raise productivity.
D) Some employees in the study disliked walking.
E) Afternoon productivity is the company's main concern.
Find the new thing. The evidence is about productivity employees *reported*. The conclusion is about raising *actual* productivity. Reported productivity shows up in the evidence. Real productivity appears for the first time in the conclusion, and the argument never connects the two.
The bridge has to connect them, and B is exactly that bridge and nothing more: the reports were accurate, so reported productivity is real productivity.
A fails on strength. "All" claims far more than the bridge needs. C is wrong for the exact same reason. D is trivia the argument never touches. E sounds managerial and means nothing; the argument works even if productivity is the company's second concern.
Find the new thing. Everything else will fall into place :)
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u/ehl-satt-lover 22h ago
In my view, what you're describing is a process that kind of skirts one's need to understand the argument--it feels like a "shortcut" to the hard work of understanding the argument's components and how they relate to one another in depth. The problem with your framing is that it can confuse new students, especially when they are learning this and SA at the same time.
SA is really the "bridge" question type. There's a gaping hole b/w premises and conclusion and the SA is the thing that the answer choice, if true, makes the conclusion 100% valid. You are seeking out a new thing to plug between the premises and conclusion so that the conclusion is 100% valid.
NA is: if the conclusion is true, what has to be true? There's really no concept "adding" anything in this question type...all one does is take what is given, the conclusion and premises, and figure out, without being critical of the argument itself, what has to be true for this conclusion to be true?
So NA process:
1. Highlight conclusion after reading stimulus
2. Ask self, if this conclusion is true (except actually say the conclusion based on content), what has to be true?
3. Read each AC and ask this again, "Okay if [conclusion] is true, does [AC] have to be true?
4. Select and reconfirm with: "If the [conclusion is true] does [AC] have to be true?
This is foolproof and doesn't ever break. Where as yours is banking on a clear "missing element" that turns a novice test taker into someone hunting for a missing premise, when that really misses the whole point of the question.
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u/Great_Lawyer_4792 22h ago
Your method confuses what must be true for the conclusion to be true with what the argument must assume for its premises to support that conclusion. Those are different questions.
Consider: “Every attorney at this firm speaks Spanish. Therefore, Maria speaks Spanish.”
The argument needs the assumption that Maria is an attorney at this firm. But your test asks, “If Maria speaks Spanish, must she be an attorney at this firm?” No. Your method rejects the assumption the argument needs.
The conclusion can be true for reasons unrelated to the premises. NA questions concern the reasoning offered, not every possible way the conclusion could be true. The right question is: “Without this assumption, do these premises still support this conclusion?”
And “bridge” is not exclusive to SA. A connection can be necessary without being sufficient. SA guarantees the conclusion; NA identifies something the argument cannot do without.
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u/ehl-satt-lover 21h ago
Not trying to dodge, but I think your characterization is off because that stimulus isn't going to ever be in a NA quesiton. Try the method for any real NA question--it works.
And I think we're generally on a different page so I'm gonna drop it--my point was just that I think your explanation is confusing af
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u/Great_Lawyer_4792 21h ago edited 21h ago
Your method can work on real questions because you’re likely doing more intuitively than you’re explaining: you’re reading ‘if the conclusion is true’ as ‘if the conclusion follows from these premises.’ That brings the argument’s reasoning back into the analysis.
Some people understand that connection intuitively without spelling it out. For students who don’t, talking about a bridge is an easy way to make that connection explicit! What’s confusing in one way can be explained better to other people in another way, so I totally understand where you’re coming from.
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u/rickrackreboot 23h ago
This was really helpful. Thank you!