What does the subject GRE measure?

Solution 1:

I know this is an old question, and excuse me for what some might consider an overly pessimistic attitude, but:

The GRE is measuring your ability to take the GRE. ETS is a private institution whose interested in maintaining the nigh forced purchasing of their product. To quote a comment in this thread:

More bluntly, it's a self-perpetuating racket by ETS who makes a bloody fortune on useless testing and selling "preparation materials" to train the subjects of their supposedly valid testing methods. Deductive logic test: if the GRE is a measure of inherent qualities, then preparation should not significantly affect a subject's score.

Ⓐ True

Ⓑ False

Ⓒ Either way, ETS makes more money

Solution 2:

Please check your implicit assumptions. It is an assumption that any test score "measures" some objectively knowable quantity in a statistical sense. For example, the claim that "IQ" tests measure intelligence. At best, there is a positive correlation between such test scores and abilities that would be considered signs of intelligence. The best measure is behaving intelligently no matter what test scores indicate. The real question is "what do you want to do and why?" and only you can answer that for yourself. One good use of tests is what you did by taking practice tests and see where you are missing abilities. They can show where you can try do better.

If your goal is to increase your mathematics proficiency, then you are on the right path. Use the tests to highlight weaknesses, but don't mistake good test scores for good proficiency. They are only positively correlated. It all depends on the actual test. A bad test can be useless. Finally, don't mistake "school mathematics" for real mathematics. It is an easy mistake to make until you have a lot of experience with real mathematics.