Some will argue a test is the fairest way to measure a child's natural aptitude, and perhaps this is true in later years.

WSJ: Conflicted Over Gifted: NYC's Gifted and Talented Test Changes

The best-known measure is, of course, the Scholastic Aptitude Test, taken by college-bound seniors only but widely used as a proxy for school performance despite its proprietor's continuous protestations that it was not designed for that purpose.

FORBES: Are We Spending Too Much On Education?