For some kinds of Logical Reasoning questions, stronger answers are better. For others, weaker answers are better. Are you having trouble keeping track of which ones are which? If you’re trying to memorize it one question type at a time, all of this will get much easier if you understand one simple rule. Here’s the fundamental principle.

If the answer is supposed to do something, stronger is better

The question types that take stronger answers are the ones that put the answer on the sufficient side of a conditional arrow. For example, “Which of the following, if true, most weakens the argument?” Or, say, “The conclusion above follows logically if which of the following is assumed?” In terms of question types, that’s mainly Weaken, Strengthen, and Sufficient Assumption questions.

Why? The answer to these kinds of questions is supposed to do something. The stronger an answer is, the more it does. If an answer, say, strengthens an argument, but also does some other stuff, it still strengthened the argument. So don’t ever question whether an answer to one of these kinds of questions is “too strong.” There is no such thing.

If the answer is supposed to have something done to it, weaker is better

You could also look at this as the answer falling on the necessary side of a conditional arrow. For example, “If the statements above are true, then which of the following must also be true?” or “The argument above requires which of the following assumptions?” The answer is supposed to be proven true, or made necessary by the argument. Soft Must be True questions (for example, “The statements above most strongly support which of the following propositions?”) also fall in this category.

Why? If you’re trying to prove the answer true, the weaker a claim is, the easier it is to prove true. So weaker answers look better. Same goes for necessary assumptions — the weaker a claim is, the more reasonably you can make the case it’s truly necessary. So when you’re doing these kinds of questions, never eliminate an answer for being “too weak.”

A note about the word “better”

In the above paragraphs, I called stronger or weaker answers “better” in certain cases. That isn’t a real LSAT concept. Answers aren’t better or worse. They’re right or wrong. Here’s what I really mean. When stronger answers are “better,” that doesn’t mean the strongest answer is right. Not even close. It doesn’t even mean that the answer needs to be strong. It just means that you should never entertain the concept that an answer might be “too strong.” No answer is ever too strong for these kinds of questions. And if you’re choosing between two similar answers, the stronger one is a better bet. Same goes for when you prefer weaker answers. Which brings us to…

Lots of answers don’t play by the above rules

There are lots of weak correct answers to the kinds of questions for which you prefer stronger answers, and strong correct answers to the kinds of questions for which you prefer weaker answers. If you’re trying to strengthen or weaken an argument, a weaker answer might be right if, say, the argument you’re trying to strengthen or weaken was premised on really weak evidence. The weak answer might do the trick while a stronger answer might be irrelevant and therefore wrong.

Likewise, if you’re doing a Must Be True question and the stimulus gives you some really strong claims, maybe the answer can be strong. Or if an argument has a really strong conclusion, there might be a strong necessary assumption. Those are just a couple examples. No answer is always too strong or weak for a given question type. If you see a really strong answer on, say, a Must be True question, you should be a little skeptical about whether you have enough evidence to prove it. But if you do, it’s right.

There’s sort of an exception, but it’s not terribly important

Must Be False questions don’t play by the above rules, at least in theory. You’re trying to do something to the answer (prove it false) so by the rules above you’d expect weaker answers to be better. The problem is that it’s easier to contradict a strong claim than a weak one. So in theory, stronger answers are better for Must be False questions.

But in practice, Must be False questions often give you really strong statements in the stimulus. When you have really strong evidence, it will often contradict even quite weak claims. And so weak answers are often correct on Must be False questions … as we’d expect from the general rule. Confusing, I know, but these questions are rare anyway, so don’t let them distract you from the general rule.

And that general rule can help guide you through confusing or difficult questions. So remember, if you’re doing something to the argument, stronger answer choices tend to be better. If you’re doing something to the answer, weaker is better. Remember this general rule, and your approach will be better too.