Confusing a Necessary Condition for a Sufficient Condition vs. Confusing a Sufficient Condition for a Necessary Condition (LSAT)

Two different answer choices might show up on the LSAT. The first says that a flaw has occurred because someone has confused a necessary condition for a sufficient condition. The other says that a flaw has occurred because someone has confused a sufficient condition for a necessary condition. These sound alike but they are different. In fact, the same question might contain both of these answers choices! 

Imagine a school teacher says, "only if you hand in the permission slip can you go on the school trip."

A student hands in the slip and thinks "I can go on the trip!"

Not exactly, no. The teacher said that handing in the slip is a necessary condition for going on the trip. The student assumed, though, that handing in the slip is all that is required for going on the trip. In LSAT lingo, the student has taken a necessary condition and confused it for a sufficient condition.

Now, instead, assume that someone says "if you score a 180 on the LSAT, you'll get into Yale Law School." A listener who scores a 175 presumes that he won't get in because he did not score a 180.

Again, incorrect. Scoring a 180, as stated, was enough to get in to Yale Law School; it was sufficient. But the listener thought it was required. Here, again in LSAT lingo, the listener has taken a sufficient condition and confused it for a necessary condition.

These two answer choices mean different things, so be sure to understand the differences!