Question: Do PSAT scores generally closely correlate to future SAT scores? Also, what are the differences in the SAT II Math IC and Math IIC? Is one "better" than the other?
For most students, the PSAT is usually their first encounter with SAT-type tests, and they take it primarily in their junior year, although some 10th graders take it, as you may have. When the PSAT is taken in 11th grade, it serves also as the Preliminary Scholastic Assessment Test/National Merit Scholarship Qualifying Test. So, the full alphabet-soup moniker ends up being: PSAT/NMSQT, which is quite a mouthful.
The PSAT is a bit easier than the full-blown SAT I. However, the scores do correlate somewhat accurately with the SAT I, keeping in mind that the advanced difficulty level of the SAT I will many times result in slightly lower scores. A crude rule of thumb states that SAT scores rise about 100 points for every year of high school. For example, if your PSAT Math + Verbal scores in 10th grade totaled 110 (50M, 60V), which translates to 1100 in SAT I scoring (just add a zero to each), you may reasonably expect to add another 100 points to that score if you take the SAT I in the spring of your junior year. That's just a crude guideline and does not take into consideration any specialized prepping that you would do (prep courses or self-study).
As for the differences between the Math IC and IIC SAT IIs, the College Board explains the difference this way:
"If you've taken fewer than three years of math, you may not have covered all of the material included on the Level IC test. For the Level IC Test, you should take at least three years of math that's equivalent to two years of algebra (algebra 1 and algebra 2) and 1 year of geometry.
"For the Level IIC Test, you need more than three years of math. You need to have taken a precalculus course (or a course in elementary functions and/or trigonometry)."
Check out the entire discussion on how to decide which test to take at:
While there, also check out the prep books that are available. One is not necessarily "better" than the other. However, if you're applying to a highly competitive college, the IIC may display your math skills in a better light, thus perhaps giving it an edge over the IC.