Does the LSAT measure IQ?

I was recently asked how well the LSAT serves as an IQ test. It does measure intelligence to an extent (USMensa uses it as one of their admissions tests). If it were purely an intellegence test, however, it would be virtually impossible to improve your score (unless, of course, you could actually raise your own IQ). There's an entire industry built around the fact that this is not true.

The reason the test (and most every other test) is so bad at showing intelligence or aptitude is that the test gets in the way of what it's testing.

There are a number of things about the LSAT--understanding how questions are phrased, what they're really looking for when they say "such-and-such," knowing exactly what to expect on each section, etc.--that can improve your score. There are quirky things that are LSAT-specific (for instance, in the real world, I can counter someone's argument by questioning their premise. On the LSAT, an answer that weakens a premise is always incorrect.) It's not as much of a carnival game as the GMAT, which is almost all about test-taking technique, but there is plenty of opportunity for improvement, especially from the scores around the median--students from 145-155 seem to be able to improve the most points-wise.

At the same time, I notice that most people eventually hit a ceiling that is very difficult to break through, and I think that finaly barrier may be the limit of their mental ability (whether it be logic, comprehension, or just the speed at which they think).

IMHO, studying for the LSAT is about removing those non-content, test-specific barriers so the test can actually do what it claims to, that is, reflect the student's actual aptitude.