Questions using a principle

Hey Trainwreck - I know there are a few key ideas that really helped me out when I was first working with Principle questions, so I'll give a few of those here. First, understand that "Principle Questions" aren't really a unique question type per se, but rather an underlying theme or concept that can appear in a number of different question types. So you see the "principle" label applied to a variety of questions based not on what the question asks you to do (like Strengthen or Must Be True etc), but rather based on the presence of a principle somewhere in the question itself. But before we get too deep into how those questions work individually, it's important to understand what "principle" actually means.

A principle is essentially a broad rule that dictates what specific decision, judgment, or action would be appropriate in a certain situation. For instance, a principle could be something like, "The seller of an item must offer a full refund if a buyer can show that the item's description is inaccurate." This is a fairly broad rule that governs the behavior of a seller (offer a refund) in a specific scenario (item inaccurately described). So we would know what to do or think in certain instances that fit this principle, like the seller's responsibilities when an item's description isn't correct, but we wouldn't know things outside the scope of the principle, like a buyer's responsibilities or other scenarios that might also warrant a refund from a seller.

The presence of a principle essentially allows you to take a broad position based on it, and then apply it in a specific manner as determined by the type of question you're working on. And that's perhaps the next thing to understand: the relationship between the stimulus and the answer choices will vary somewhat based on what type of question the principle appears in. So you may be given a broad rule in the stimulus and asked to apply it to the specifics of each answer choice, or each answer choice may give a broad rule and you'll be asked to apply those rules to the specific scenario in the stimulus. This is important because it really serves to add a bit of structure to your approach to these questions (and this expands on Noah's point). Let me explain...

In a Must Be True type question where you use the information in the stimulus (the initial information with which you're provided) to ultimately prove an answer choice is valid, the broad rule/principle will be given in the stimulus and the five answer choices will each present a specific scenario/situation, one of which will conform to the broad principle given. So you consider the broad rule given and then find the answer that follows from the application of the principle.

The other common way in which you can encounter principles is when they are given in the answer choices. Here, each answer choice will contain a broad rule that serves as a premise of sorts to the specific argument in the stimulus, and the correct answer choice will support or prove the conclusion (this the Strengthen idea).

So either way you have to understand what actions/decisions would be appropriate based on the broad principle given, and then see how (or if) those actions/decisions would come into play as you consider a specific scenario. In Must Be True the correct answer choice will contain a specific situation that follows from the principle, and in a Strengthen/Justify type question the correct answer choice will give a principle that supports the specifics of the stimulus.

I hope this helps!