Everyone knows that the SAT and the GRE are total scams that don't have any correlation with college/grad school success... but how indicative are LSAT scores of first year performance?
In short, for an individual, whether you get a great LSAT or a mediocre one will bear little on your grades.
LSATs are indicative in the same way that SATs, or an intelligence test, or even a timed New York Times crossword puzzle would be–each tries to test one’s ability to think under pressure. What they cannot do is test drive, interest, commitment, and the variety of other intangible things that bear 5 times as much relevance to performance on law school exams than does intelligence (albeit a special type of intelligence).
Over thousands of persons, the thousands who get 160s will do better than the group that gets 155, but that is because since the intangibles are evenly distributed among the masses, and the only true tangible element left to consider is the LSAT score.
The truth is whether you like your professors or not, whether you fall in love or out of love, or whether you think your school has bad food will have more impact on your grades as to whether you snuck in a few lucky guesses on the LSAT. Love, bad food, and sadistic professors are not any more of less likely to afflict 160s than 150s, so hence the remnant LSAT differential.
In my experience, there were plenty of 168s who were at the bottom of the class, and plenty of 152s who were stars. All worked reasonably hard, studied, and took the work seriously. But, I am sure if the entire school was considered, over 1,000 students you'd see a coorelation. But over a dozen or so, none.