Many LSAT test-takers think everyone has one "true" LSAT score, just like everyone supposedly has one "true" IQ score. Of course, taking an IQ test at age 20 and age 50 would likely generate different results. But I'd imagine that even taking two IQ tests a week or a day apart would likely generate slightly different results.
So, why do so many people think they should keep getting approximately the same LSAT score when taking timed LSAT PrepTests before Test Day?
This idea may have something to do with intuitions about grades, but even grades aren't necessarily constant. While people tend to be jealous of the person who "gets straight A's," I can't think of someone who got only As. I often got As, but I also got A-s and even (gasp) B+s.
For some people, this comes from the idea that the LSAT is a test you can study for, and improve on. "I've studied my way to a 170, so that's now my true score. How could I possibly get significantly lower scores? Am I getting dumber?"
Reasons your LSAT scores can fluctuate:
People often fail to consider that there is an element of randomness involved on standardized exams.
-With a limit on the number of questions that can be asked, some concepts that you're good at might not appear, leading your score to be lower than it would've been otherwise.
-A concept that doesn't always appear might show up on your test. If it's something you're shaky on, again, your score might end up being lower than it would've been otherwise.
As always, the safest course of action to guard against unanticipated low scores is to learn everything. No easy answers here, sorry.
Some other factors that lead to score drops - burnout, sleep deprivation, stress, and poor health. Make sure to get enough sleep, eat well, and get moderate exercise. This stuff really makes a difference.
