For screening purposes, there are a few brief intelligence measures that are valid for four-year-olds, such as the RIAS, WRIT, and KBIT2. It would certainly be cheaper than the WPPSI-IV or SBV, but not by enough to make it feasible as universal screening. The instruments themselves are about a quarter the price of one of the comprehensives, while the cost in examiner time would be about 1/3 to 1/2.
IQ is positively correlated with academic achievement. Our elementary school, like many others, does not give letter grades, but report cards do have marks from 1 to 4 in reading, math, and other subjects. A composite IQ prediction based on "brief intelligence measures" and grades could be created. It will miss high IQ children who are getting bad grades for some reason, but that is better than missing all gifted children in grades 1 and 2 by not screening them.
