One of the common questions that comes up with students studying for the LSAT is how do Justify/Sufficient Assumption questions work, and how do they differ from regular Assumption/Necessary Assumption questions? The mere fact that there are different types of assumption questions is part of the problem. But the unique way that these questions work also causes issues. Let’s take a closer look at this question type and try to understand the big picture!
Defining Terms
Let’s make sure we’re all talking about the same thing. In PowerScore terminology, we call these Justify the Conclusion questions, which you sometimes see elsewhere called Sufficient Assumption. The two types are identical:
PowerScore Name = Alternate Name
Justify the Conclusion = Sufficient Assumption (SA)
Assumption = Necessary Assumption (NA)
Why the Different Names?
It’s because of LSAT history. In the early 90s, Sufficient Assumptions appeared so infrequently that the type wasn’t really formally understood and had never been identified by LSAC or any test preparation company. All questions in this logical area were called Assumptions, hence that holdover. For PowerScore, it was around 1997 where we saw a question that had Assumption-style language but had an answer that most definitely wasn’t an assumption or a mistake, and at least for us, that’s when I coined the term Justify the Conclusion for these questions. A few years later LSAC published the SuperPrep, which included their explanations. That’s when they first used the terms Sufficient Assumption and Necessary Assumption, and those terms have become popular enough that we all now use the term sufficient/necessary assumption frequently.
What Are You Being Asked to Do?
So, now we can identify the names involved, but what is the exact task that a Justify question requires you to perform? Justify questions ask you to add a piece to the argument that then produces the conclusion. It’s like adding the last piece of the puzzle, and thereafter you can see the entire picture properly. The phrase Justify the Conclusion reflects that the correct answer